coverage: Include the highest counter ID seen in `.cov-map` dumps

When making changes that have a large impact on coverage counter creation, this makes it easier to see whether the number of physical counters has changed. (The highest counter ID seen in coverage maps is not necessarily the same as the number of physical counters actually used by the instrumented code, but it's the best approximation we can get from looking only at the coverage maps, and it should be reasonably accurate in most cases.)
2024-10-08 13:13:05 +11:00 · 2024-10-08 13:13:05 +11:00 · 599f95ecc2
parent ce697f919d
commit 599f95ecc2
88 changed files with 338 additions and 0 deletions
--- a/src/tools/coverage-dump/src/covfun.rs
+++ b/src/tools/coverage-dump/src/covfun.rs
@ -56,6 +56,7 @@ pub(crate) fn dump_covfun_mappings(
            expression_resolver.push_operands(lhs, rhs);
        }

+        let mut max_counter = None;
        for i in 0..num_files {
            let num_mappings = parser.read_uleb128_u32()?;
            println!("Number of file {i} mappings: {num_mappings}");
@ -63,6 +64,11 @@ pub(crate) fn dump_covfun_mappings(
            for _ in 0..num_mappings {
                let (kind, region) = parser.read_mapping_kind_and_region()?;
                println!("- {kind:?} at {region:?}");
+                kind.for_each_term(|term| {
+                    if let CovTerm::Counter(n) = term {
+                        max_counter = max_counter.max(Some(n));
+                    }
+                });

                match kind {
                    // Also print expression mappings in resolved form.
@ -83,6 +89,16 @@ pub(crate) fn dump_covfun_mappings(
        }

        parser.ensure_empty()?;
+
+        // Printing the highest counter ID seen in the functions mappings makes
+        // it easier to determine whether a change to coverage instrumentation
+        // has increased or decreased the number of physical counters needed.
+        // (It's possible for the generated code to have more counters that
+        // aren't used by any mappings, but that should hopefully be rare.)
+        println!("Highest counter ID seen: {}", match max_counter {
+            Some(id) => format!("c{id}"),
+            None => "(none)".to_owned(),
+        });
        println!();
    }
    Ok(())
@ -271,6 +287,32 @@ enum MappingKind {
    },
 }

+impl MappingKind {
+    fn for_each_term(&self, mut callback: impl FnMut(CovTerm)) {
+        match *self {
+            Self::Code(term) => callback(term),
+            Self::Gap(term) => callback(term),
+            Self::Expansion(_id) => {}
+            Self::Skip => {}
+            Self::Branch { r#true, r#false } => {
+                callback(r#true);
+                callback(r#false);
+            }
+            Self::MCDCBranch {
+                r#true,
+                r#false,
+                condition_id: _,
+                true_next_id: _,
+                false_next_id: _,
+            } => {
+                callback(r#true);
+                callback(r#false);
+            }
+            Self::MCDCDecision { bitmap_idx: _, conditions_num: _ } => {}
+        }
+    }
+}
+
 struct MappingRegion {
    /// Offset of this region's start line, relative to the *start line* of
    /// the *previous mapping* (or 0). Line numbers are 1-based.
--- a/tests/coverage/abort.cov-map
+++ b/tests/coverage/abort.cov-map
@ -34,6 +34,7 @@ Number of file 0 mappings: 13
 - Code(Expression(9, Add)) at (prev + 1, 9) to (start + 0, 23)
    = (c1 + c2)
 - Code(Counter(3)) at (prev + 2, 5) to (start + 1, 2)
+Highest counter ID seen: c5

 Function name: abort::might_abort
 Raw bytes (21): 0x[01, 01, 01, 01, 05, 03, 01, 03, 01, 01, 14, 05, 02, 09, 01, 24, 02, 02, 0c, 03, 02]
@ -46,4 +47,5 @@ Number of file 0 mappings: 3
 - Code(Counter(1)) at (prev + 2, 9) to (start + 1, 36)
 - Code(Expression(0, Sub)) at (prev + 2, 12) to (start + 3, 2)
    = (c0 - c1)
+Highest counter ID seen: c1

--- a/tests/coverage/assert-ne.cov-map
+++ b/tests/coverage/assert-ne.cov-map
@ -10,4 +10,5 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 2, 13) to (start + 0, 19)
    = (c0 - c1)
 - Code(Counter(2)) at (prev + 3, 5) to (start + 1, 2)
+Highest counter ID seen: c2

--- a/tests/coverage/assert.cov-map
+++ b/tests/coverage/assert.cov-map
@ -25,6 +25,7 @@ Number of file 0 mappings: 9
 - Code(Expression(6, Add)) at (prev + 1, 9) to (start + 0, 23)
    = (c1 + (c2 + c3))
 - Code(Counter(4)) at (prev + 2, 5) to (start + 1, 2)
+Highest counter ID seen: c4

 Function name: assert::might_fail_assert
 Raw bytes (21): 0x[01, 01, 01, 01, 05, 03, 01, 04, 01, 02, 0f, 02, 02, 25, 00, 3d, 05, 01, 01, 00, 02]
@ -37,4 +38,5 @@ Number of file 0 mappings: 3
 - Code(Expression(0, Sub)) at (prev + 2, 37) to (start + 0, 61)
    = (c0 - c1)
 - Code(Counter(1)) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: c1

--- a/tests/coverage/assert_not.cov-map
+++ b/tests/coverage/assert_not.cov-map
@ -13,4 +13,5 @@ Number of file 0 mappings: 5
 - Code(Counter(3)) at (prev + 1, 5) to (start + 0, 22)
 - Code(Expression(1, Sub)) at (prev + 1, 1) to (start + 0, 2)
    = (c3 - Zero)
+Highest counter ID seen: c3

--- a/tests/coverage/async.cov-map
+++ b/tests/coverage/async.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 12, 1) to (start + 0, 25)
+Highest counter ID seen: c0

 Function name: async::c::{closure#0}
 Raw bytes (26): 0x[01, 01, 01, 01, 05, 04, 01, 0c, 19, 01, 0e, 05, 02, 09, 00, 0a, 02, 02, 09, 00, 0a, 01, 02, 01, 00, 02]
@ -18,6 +19,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 2, 9) to (start + 0, 10)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 2, 1) to (start + 0, 2)
+Highest counter ID seen: c1

 Function name: async::d
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 14, 01, 00, 14]
@ -26,6 +28,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 20, 1) to (start + 0, 20)
+Highest counter ID seen: c0

 Function name: async::d::{closure#0}
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 14, 14, 00, 19]
@ -34,6 +37,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 20, 20) to (start + 0, 25)
+Highest counter ID seen: c0

 Function name: async::e (unused)
 Raw bytes (9): 0x[01, 01, 00, 01, 00, 16, 01, 00, 14]
@ -42,6 +46,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 22, 1) to (start + 0, 20)
+Highest counter ID seen: (none)

 Function name: async::e::{closure#0} (unused)
 Raw bytes (9): 0x[01, 01, 00, 01, 00, 16, 14, 00, 19]
@ -50,6 +55,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 22, 20) to (start + 0, 25)
+Highest counter ID seen: (none)

 Function name: async::f
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 18, 01, 00, 14]
@ -58,6 +64,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 24, 1) to (start + 0, 20)
+Highest counter ID seen: c0

 Function name: async::f::{closure#0}
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 18, 14, 00, 19]
@ -66,6 +73,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 24, 20) to (start + 0, 25)
+Highest counter ID seen: c0

 Function name: async::foo (unused)
 Raw bytes (9): 0x[01, 01, 00, 01, 00, 1a, 01, 00, 1e]
@ -74,6 +82,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 26, 1) to (start + 0, 30)
+Highest counter ID seen: (none)

 Function name: async::foo::{closure#0} (unused)
 Raw bytes (9): 0x[01, 01, 00, 01, 00, 1a, 1e, 00, 2d]
@ -82,6 +91,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 26, 30) to (start + 0, 45)
+Highest counter ID seen: (none)

 Function name: async::g
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 1c, 01, 00, 17]
@ -90,6 +100,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 28, 1) to (start + 0, 23)
+Highest counter ID seen: c0

 Function name: async::g::{closure#0} (unused)
 Raw bytes (59): 0x[01, 01, 00, 0b, 00, 1c, 17, 01, 0c, 00, 02, 09, 00, 0a, 00, 00, 0e, 00, 17, 00, 00, 1b, 00, 1c, 00, 00, 20, 00, 22, 00, 01, 09, 00, 0a, 00, 00, 0e, 00, 17, 00, 00, 1b, 00, 1c, 00, 00, 20, 00, 22, 00, 01, 0e, 00, 10, 00, 02, 01, 00, 02]
@ -108,6 +119,7 @@ Number of file 0 mappings: 11
 - Code(Zero) at (prev + 0, 32) to (start + 0, 34)
 - Code(Zero) at (prev + 1, 14) to (start + 0, 16)
 - Code(Zero) at (prev + 2, 1) to (start + 0, 2)
+Highest counter ID seen: (none)

 Function name: async::h
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 24, 01, 00, 16]
@ -116,6 +128,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 36, 1) to (start + 0, 22)
+Highest counter ID seen: c0

 Function name: async::h::{closure#0} (unused)
 Raw bytes (39): 0x[01, 01, 00, 07, 00, 24, 16, 03, 0c, 00, 04, 09, 00, 0a, 00, 00, 0e, 00, 19, 00, 00, 1a, 00, 1b, 00, 00, 20, 00, 22, 00, 01, 0e, 00, 10, 00, 02, 01, 00, 02]
@ -130,6 +143,7 @@ Number of file 0 mappings: 7
 - Code(Zero) at (prev + 0, 32) to (start + 0, 34)
 - Code(Zero) at (prev + 1, 14) to (start + 0, 16)
 - Code(Zero) at (prev + 2, 1) to (start + 0, 2)
+Highest counter ID seen: (none)

 Function name: async::i
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 2d, 01, 00, 13]
@ -138,6 +152,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 45, 1) to (start + 0, 19)
+Highest counter ID seen: c0

 Function name: async::i::{closure#0}
 Raw bytes (63): 0x[01, 01, 02, 07, 19, 11, 15, 0b, 01, 2d, 13, 04, 0c, 09, 05, 09, 00, 0a, 01, 00, 0e, 00, 18, 05, 00, 1c, 00, 21, 09, 00, 27, 00, 30, 15, 01, 09, 00, 0a, 0d, 00, 0e, 00, 17, 1d, 00, 1b, 00, 20, 15, 00, 24, 00, 26, 19, 01, 0e, 00, 10, 03, 02, 01, 00, 02]
@ -159,6 +174,7 @@ Number of file 0 mappings: 11
 - Code(Counter(6)) at (prev + 1, 14) to (start + 0, 16)
 - Code(Expression(0, Add)) at (prev + 2, 1) to (start + 0, 2)
    = ((c4 + c5) + c6)
+Highest counter ID seen: c7

 Function name: async::j
 Raw bytes (58): 0x[01, 01, 02, 07, 0d, 05, 09, 0a, 01, 38, 01, 00, 0d, 01, 0b, 0b, 00, 0c, 05, 01, 09, 00, 0a, 01, 00, 0e, 00, 1b, 05, 00, 1f, 00, 27, 09, 01, 09, 00, 0a, 11, 00, 0e, 00, 1a, 09, 00, 1e, 00, 20, 0d, 01, 0e, 00, 10, 03, 02, 01, 00, 02]
@ -179,6 +195,7 @@ Number of file 0 mappings: 10
 - Code(Counter(3)) at (prev + 1, 14) to (start + 0, 16)
 - Code(Expression(0, Add)) at (prev + 2, 1) to (start + 0, 2)
    = ((c1 + c2) + c3)
+Highest counter ID seen: c4

 Function name: async::j::c
 Raw bytes (26): 0x[01, 01, 01, 01, 05, 04, 01, 3a, 05, 01, 12, 05, 02, 0d, 00, 0e, 02, 02, 0d, 00, 0e, 01, 02, 05, 00, 06]
@ -192,6 +209,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 2, 13) to (start + 0, 14)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 2, 5) to (start + 0, 6)
+Highest counter ID seen: c1

 Function name: async::j::d
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 41, 05, 00, 17]
@ -200,6 +218,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 65, 5) to (start + 0, 23)
+Highest counter ID seen: c0

 Function name: async::j::f
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 42, 05, 00, 17]
@ -208,6 +227,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 66, 5) to (start + 0, 23)
+Highest counter ID seen: c0

 Function name: async::k (unused)
 Raw bytes (29): 0x[01, 01, 00, 05, 00, 4a, 01, 01, 0c, 00, 02, 0e, 00, 10, 00, 01, 0e, 00, 10, 00, 01, 0e, 00, 10, 00, 02, 01, 00, 02]
@ -220,6 +240,7 @@ Number of file 0 mappings: 5
 - Code(Zero) at (prev + 1, 14) to (start + 0, 16)
 - Code(Zero) at (prev + 1, 14) to (start + 0, 16)
 - Code(Zero) at (prev + 2, 1) to (start + 0, 2)
+Highest counter ID seen: (none)

 Function name: async::l
 Raw bytes (37): 0x[01, 01, 04, 01, 07, 05, 09, 0f, 02, 09, 05, 05, 01, 52, 01, 01, 0c, 02, 02, 0e, 00, 10, 05, 01, 0e, 00, 10, 09, 01, 0e, 00, 10, 0b, 02, 01, 00, 02]
@ -238,6 +259,7 @@ Number of file 0 mappings: 5
 - Code(Counter(2)) at (prev + 1, 14) to (start + 0, 16)
 - Code(Expression(2, Add)) at (prev + 2, 1) to (start + 0, 2)
    = ((c2 + c1) + (c0 - (c1 + c2)))
+Highest counter ID seen: c2

 Function name: async::m
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 5a, 01, 00, 19]
@ -246,6 +268,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 90, 1) to (start + 0, 25)
+Highest counter ID seen: c0

 Function name: async::m::{closure#0} (unused)
 Raw bytes (9): 0x[01, 01, 00, 01, 00, 5a, 19, 00, 22]
@ -254,6 +277,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 90, 25) to (start + 0, 34)
+Highest counter ID seen: (none)

 Function name: async::main
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 5c, 01, 08, 02]
@ -262,4 +286,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 92, 1) to (start + 8, 2)
+Highest counter ID seen: c0

--- a/tests/coverage/async2.cov-map
+++ b/tests/coverage/async2.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 16, 1) to (start + 0, 23)
+Highest counter ID seen: c0

 Function name: async2::async_func::{closure#0}
 Raw bytes (24): 0x[01, 01, 00, 04, 01, 10, 17, 03, 09, 05, 03, 0a, 02, 06, 00, 02, 06, 00, 07, 01, 01, 01, 00, 02]
@ -16,6 +17,7 @@ Number of file 0 mappings: 4
 - Code(Counter(1)) at (prev + 3, 10) to (start + 2, 6)
 - Code(Zero) at (prev + 2, 6) to (start + 0, 7)
 - Code(Counter(0)) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: c1

 Function name: async2::async_func_just_println
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 18, 01, 00, 24]
@ -24,6 +26,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 24, 1) to (start + 0, 36)
+Highest counter ID seen: c0

 Function name: async2::async_func_just_println::{closure#0}
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 18, 24, 02, 02]
@ -32,6 +35,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 24, 36) to (start + 2, 2)
+Highest counter ID seen: c0

 Function name: async2::main
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 1c, 01, 07, 02]
@ -40,6 +44,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 28, 1) to (start + 7, 2)
+Highest counter ID seen: c0

 Function name: async2::non_async_func
 Raw bytes (24): 0x[01, 01, 00, 04, 01, 08, 01, 03, 09, 05, 03, 0a, 02, 06, 00, 02, 06, 00, 07, 01, 01, 01, 00, 02]
@ -51,4 +56,5 @@ Number of file 0 mappings: 4
 - Code(Counter(1)) at (prev + 3, 10) to (start + 2, 6)
 - Code(Zero) at (prev + 2, 6) to (start + 0, 7)
 - Code(Counter(0)) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: c1

--- a/tests/coverage/async_block.cov-map
+++ b/tests/coverage/async_block.cov-map
@ -12,6 +12,7 @@ Number of file 0 mappings: 6
 - Code(Counter(1)) at (prev + 0, 20) to (start + 1, 22)
 - Code(Counter(1)) at (prev + 7, 10) to (start + 2, 6)
 - Code(Counter(0)) at (prev + 3, 1) to (start + 0, 2)
+Highest counter ID seen: c1

 Function name: async_block::main::{closure#0}
 Raw bytes (26): 0x[01, 01, 01, 01, 05, 04, 01, 0a, 1c, 01, 17, 05, 01, 18, 02, 0e, 02, 02, 14, 02, 0e, 01, 03, 09, 00, 0a]
@ -25,4 +26,5 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 2, 20) to (start + 2, 14)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 3, 9) to (start + 0, 10)
+Highest counter ID seen: c1

--- a/tests/coverage/attr/impl.cov-map
+++ b/tests/coverage/attr/impl.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 14, 5) to (start + 0, 19)
+Highest counter ID seen: (none)

 Function name: <impl::MyStruct>::on_inherit (unused)
 Raw bytes (9): 0x[01, 01, 00, 01, 00, 16, 05, 00, 17]
@ -13,6 +14,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 22, 5) to (start + 0, 23)
+Highest counter ID seen: (none)

 Function name: <impl::MyStruct>::on_on (unused)
 Raw bytes (9): 0x[01, 01, 00, 01, 00, 19, 05, 00, 12]
@ -21,4 +23,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 25, 5) to (start + 0, 18)
+Highest counter ID seen: (none)

--- a/tests/coverage/attr/module.cov-map
+++ b/tests/coverage/attr/module.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 12, 5) to (start + 0, 15)
+Highest counter ID seen: (none)

 Function name: module::on::inherit (unused)
 Raw bytes (9): 0x[01, 01, 00, 01, 00, 14, 05, 00, 14]
@ -13,6 +14,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 20, 5) to (start + 0, 20)
+Highest counter ID seen: (none)

 Function name: module::on::on (unused)
 Raw bytes (9): 0x[01, 01, 00, 01, 00, 17, 05, 00, 0f]
@ -21,4 +23,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 23, 5) to (start + 0, 15)
+Highest counter ID seen: (none)

--- a/tests/coverage/attr/nested.cov-map
+++ b/tests/coverage/attr/nested.cov-map
@ -6,6 +6,7 @@ Number of expressions: 0
 Number of file 0 mappings: 2
 - Code(Counter(0)) at (prev + 63, 1) to (start + 1, 15)
 - Code(Counter(0)) at (prev + 11, 5) to (start + 1, 2)
+Highest counter ID seen: c0

 Function name: nested::closure_tail
 Raw bytes (14): 0x[01, 01, 00, 02, 01, 4e, 01, 01, 0f, 01, 11, 05, 01, 02]
@ -15,4 +16,5 @@ Number of expressions: 0
 Number of file 0 mappings: 2
 - Code(Counter(0)) at (prev + 78, 1) to (start + 1, 15)
 - Code(Counter(0)) at (prev + 17, 5) to (start + 1, 2)
+Highest counter ID seen: c0

--- a/tests/coverage/attr/off-on-sandwich.cov-map
+++ b/tests/coverage/attr/off-on-sandwich.cov-map
@ -6,6 +6,7 @@ Number of expressions: 0
 Number of file 0 mappings: 2
 - Code(Counter(0)) at (prev + 15, 5) to (start + 2, 18)
 - Code(Counter(0)) at (prev + 7, 5) to (start + 0, 6)
+Highest counter ID seen: c0

 Function name: off_on_sandwich::sparse_a::sparse_b::sparse_c
 Raw bytes (14): 0x[01, 01, 00, 02, 01, 21, 09, 02, 17, 01, 0b, 09, 00, 0a]
@ -15,6 +16,7 @@ Number of expressions: 0
 Number of file 0 mappings: 2
 - Code(Counter(0)) at (prev + 33, 9) to (start + 2, 23)
 - Code(Counter(0)) at (prev + 11, 9) to (start + 0, 10)
+Highest counter ID seen: c0

 Function name: off_on_sandwich::sparse_a::sparse_b::sparse_c::sparse_d
 Raw bytes (14): 0x[01, 01, 00, 02, 01, 24, 0d, 02, 1b, 01, 07, 0d, 00, 0e]
@ -24,4 +26,5 @@ Number of expressions: 0
 Number of file 0 mappings: 2
 - Code(Counter(0)) at (prev + 36, 13) to (start + 2, 27)
 - Code(Counter(0)) at (prev + 7, 13) to (start + 0, 14)
+Highest counter ID seen: c0

--- a/tests/coverage/await_ready.cov-map
+++ b/tests/coverage/await_ready.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 15, 1) to (start + 0, 30)
+Highest counter ID seen: c0

 Function name: await_ready::await_ready::{closure#0}
 Raw bytes (14): 0x[01, 01, 00, 02, 01, 0f, 1e, 03, 0f, 05, 04, 01, 00, 02]
@ -14,4 +15,5 @@ Number of expressions: 0
 Number of file 0 mappings: 2
 - Code(Counter(0)) at (prev + 15, 30) to (start + 3, 15)
 - Code(Counter(1)) at (prev + 4, 1) to (start + 0, 2)
+Highest counter ID seen: c1

--- a/tests/coverage/bad_counter_ids.cov-map
+++ b/tests/coverage/bad_counter_ids.cov-map
@ -6,6 +6,7 @@ Number of expressions: 0
 Number of file 0 mappings: 2
 - Code(Counter(0)) at (prev + 36, 1) to (start + 2, 31)
 - Code(Zero) at (prev + 3, 1) to (start + 0, 2)
+Highest counter ID seen: c0

 Function name: bad_counter_ids::eq_bad_message
 Raw bytes (21): 0x[01, 01, 01, 01, 00, 03, 01, 29, 01, 02, 0f, 02, 02, 20, 00, 2b, 00, 01, 01, 00, 02]
@ -18,6 +19,7 @@ Number of file 0 mappings: 3
 - Code(Expression(0, Sub)) at (prev + 2, 32) to (start + 0, 43)
    = (c0 - Zero)
 - Code(Zero) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: c0

 Function name: bad_counter_ids::eq_good
 Raw bytes (14): 0x[01, 01, 00, 02, 01, 10, 01, 02, 1f, 05, 03, 01, 00, 02]
@ -27,6 +29,7 @@ Number of expressions: 0
 Number of file 0 mappings: 2
 - Code(Counter(0)) at (prev + 16, 1) to (start + 2, 31)
 - Code(Counter(1)) at (prev + 3, 1) to (start + 0, 2)
+Highest counter ID seen: c1

 Function name: bad_counter_ids::eq_good_message
 Raw bytes (19): 0x[01, 01, 00, 03, 01, 15, 01, 02, 0f, 00, 02, 20, 00, 2b, 05, 01, 01, 00, 02]
@ -37,6 +40,7 @@ Number of file 0 mappings: 3
 - Code(Counter(0)) at (prev + 21, 1) to (start + 2, 15)
 - Code(Zero) at (prev + 2, 32) to (start + 0, 43)
 - Code(Counter(1)) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: c1

 Function name: bad_counter_ids::ne_bad
 Raw bytes (14): 0x[01, 01, 00, 02, 01, 2e, 01, 02, 1f, 00, 03, 01, 00, 02]
@ -46,6 +50,7 @@ Number of expressions: 0
 Number of file 0 mappings: 2
 - Code(Counter(0)) at (prev + 46, 1) to (start + 2, 31)
 - Code(Zero) at (prev + 3, 1) to (start + 0, 2)
+Highest counter ID seen: c0

 Function name: bad_counter_ids::ne_bad_message
 Raw bytes (19): 0x[01, 01, 00, 03, 01, 33, 01, 02, 0f, 05, 02, 20, 00, 2b, 00, 01, 01, 00, 02]
@ -56,6 +61,7 @@ Number of file 0 mappings: 3
 - Code(Counter(0)) at (prev + 51, 1) to (start + 2, 15)
 - Code(Counter(1)) at (prev + 2, 32) to (start + 0, 43)
 - Code(Zero) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: c1

 Function name: bad_counter_ids::ne_good
 Raw bytes (16): 0x[01, 01, 01, 01, 00, 02, 01, 1a, 01, 02, 1f, 02, 03, 01, 00, 02]
@ -67,6 +73,7 @@ Number of file 0 mappings: 2
 - Code(Counter(0)) at (prev + 26, 1) to (start + 2, 31)
 - Code(Expression(0, Sub)) at (prev + 3, 1) to (start + 0, 2)
    = (c0 - Zero)
+Highest counter ID seen: c0

 Function name: bad_counter_ids::ne_good_message
 Raw bytes (21): 0x[01, 01, 01, 01, 00, 03, 01, 1f, 01, 02, 0f, 00, 02, 20, 00, 2b, 02, 01, 01, 00, 02]
@ -79,4 +86,5 @@ Number of file 0 mappings: 3
 - Code(Zero) at (prev + 2, 32) to (start + 0, 43)
 - Code(Expression(0, Sub)) at (prev + 1, 1) to (start + 0, 2)
    = (c0 - Zero)
+Highest counter ID seen: c0

--- a/tests/coverage/bench.cov-map
+++ b/tests/coverage/bench.cov-map
@ -5,4 +5,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 8, 1) to (start + 0, 39)
+Highest counter ID seen: c0

--- a/tests/coverage/branch/generics.cov-map
+++ b/tests/coverage/branch/generics.cov-map
@ -13,6 +13,7 @@ Number of file 0 mappings: 5
 - Code(Expression(0, Sub)) at (prev + 2, 12) to (start + 2, 6)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 3, 1) to (start + 0, 2)
+Highest counter ID seen: c1

 Function name: generics::print_size::<u32>
 Raw bytes (33): 0x[01, 01, 01, 01, 05, 05, 01, 06, 01, 01, 24, 20, 05, 02, 01, 08, 00, 24, 05, 00, 25, 02, 06, 02, 02, 0c, 02, 06, 01, 03, 01, 00, 02]
@ -29,6 +30,7 @@ Number of file 0 mappings: 5
 - Code(Expression(0, Sub)) at (prev + 2, 12) to (start + 2, 6)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 3, 1) to (start + 0, 2)
+Highest counter ID seen: c1

 Function name: generics::print_size::<u64>
 Raw bytes (33): 0x[01, 01, 01, 01, 05, 05, 01, 06, 01, 01, 24, 20, 05, 02, 01, 08, 00, 24, 05, 00, 25, 02, 06, 02, 02, 0c, 02, 06, 01, 03, 01, 00, 02]
@ -45,4 +47,5 @@ Number of file 0 mappings: 5
 - Code(Expression(0, Sub)) at (prev + 2, 12) to (start + 2, 6)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 3, 1) to (start + 0, 2)
+Highest counter ID seen: c1

--- a/tests/coverage/branch/guard.cov-map
+++ b/tests/coverage/branch/guard.cov-map
@ -29,4 +29,5 @@ Number of file 0 mappings: 13
    = (c1 + c2)
 - Code(Expression(2, Add)) at (prev + 4, 1) to (start + 0, 2)
    = ((((c1 + c2) + c3) + c4) + c5)
+Highest counter ID seen: c7

--- a/tests/coverage/branch/if-let.cov-map
+++ b/tests/coverage/branch/if-let.cov-map
@ -16,6 +16,7 @@ Number of file 0 mappings: 7
    = (c1 - c2)
 - Code(Counter(2)) at (prev + 2, 12) to (start + 2, 6)
 - Code(Counter(1)) at (prev + 3, 5) to (start + 1, 2)
+Highest counter ID seen: c2

 Function name: if_let::if_let_chain
 Raw bytes (66): 0x[01, 01, 04, 01, 05, 05, 09, 0f, 0d, 05, 09, 0a, 01, 17, 01, 00, 33, 20, 02, 05, 01, 0c, 00, 13, 02, 00, 11, 00, 12, 01, 00, 16, 00, 17, 20, 0d, 09, 01, 10, 00, 17, 0d, 00, 15, 00, 16, 02, 00, 1a, 00, 1b, 0d, 01, 05, 03, 06, 0f, 03, 0c, 02, 06, 0b, 03, 05, 01, 02]
@ -45,4 +46,5 @@ Number of file 0 mappings: 10
    = (c1 + c2)
 - Code(Expression(2, Add)) at (prev + 3, 5) to (start + 1, 2)
    = ((c1 + c2) + c3)
+Highest counter ID seen: c3

--- a/tests/coverage/branch/if.cov-map
+++ b/tests/coverage/branch/if.cov-map
@ -22,6 +22,7 @@ Number of file 0 mappings: 8
    = (c3 + (c1 - c2))
 - Code(Expression(2, Add)) at (prev + 3, 1) to (start + 0, 2)
    = (c4 + (c3 + (c1 - c2)))
+Highest counter ID seen: c4

 Function name: if::branch_not
 Raw bytes (116): 0x[01, 01, 07, 05, 09, 05, 0d, 05, 0d, 05, 11, 05, 11, 05, 15, 05, 15, 12, 01, 0c, 01, 01, 10, 05, 03, 08, 00, 09, 20, 09, 02, 00, 08, 00, 09, 09, 01, 09, 00, 11, 02, 01, 06, 00, 07, 05, 01, 08, 00, 0a, 20, 0a, 0d, 00, 08, 00, 0a, 0a, 00, 0b, 02, 06, 0d, 02, 06, 00, 07, 05, 01, 08, 00, 0b, 20, 11, 12, 00, 08, 00, 0b, 11, 00, 0c, 02, 06, 12, 02, 06, 00, 07, 05, 01, 08, 00, 0c, 20, 1a, 15, 00, 08, 00, 0c, 1a, 00, 0d, 02, 06, 15, 02, 06, 00, 07, 05, 01, 01, 00, 02]
@ -66,6 +67,7 @@ Number of file 0 mappings: 18
    = (c1 - c5)
 - Code(Counter(5)) at (prev + 2, 6) to (start + 0, 7)
 - Code(Counter(1)) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: c5

 Function name: if::branch_not_as
 Raw bytes (90): 0x[01, 01, 05, 05, 09, 05, 0d, 05, 0d, 05, 11, 05, 11, 0e, 01, 1d, 01, 01, 10, 05, 03, 08, 00, 14, 20, 02, 09, 00, 08, 00, 14, 02, 00, 15, 02, 06, 09, 02, 06, 00, 07, 05, 01, 08, 00, 15, 20, 0d, 0a, 00, 08, 00, 15, 0d, 00, 16, 02, 06, 0a, 02, 06, 00, 07, 05, 01, 08, 00, 16, 20, 12, 11, 00, 08, 00, 16, 12, 00, 17, 02, 06, 11, 02, 06, 00, 07, 05, 01, 01, 00, 02]
@ -101,6 +103,7 @@ Number of file 0 mappings: 14
    = (c1 - c4)
 - Code(Counter(4)) at (prev + 2, 6) to (start + 0, 7)
 - Code(Counter(1)) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: c4

 Function name: if::branch_or
 Raw bytes (56): 0x[01, 01, 04, 05, 09, 09, 0d, 0f, 11, 09, 0d, 08, 01, 35, 01, 01, 10, 05, 03, 08, 00, 09, 20, 09, 02, 00, 08, 00, 09, 02, 00, 0d, 00, 0e, 20, 0d, 11, 00, 0d, 00, 0e, 0f, 00, 0f, 02, 06, 11, 02, 0c, 02, 06, 0b, 03, 01, 00, 02]
@ -127,4 +130,5 @@ Number of file 0 mappings: 8
 - Code(Counter(4)) at (prev + 2, 12) to (start + 2, 6)
 - Code(Expression(2, Add)) at (prev + 3, 1) to (start + 0, 2)
    = ((c2 + c3) + c4)
+Highest counter ID seen: c4

--- a/tests/coverage/branch/lazy-boolean.cov-map
+++ b/tests/coverage/branch/lazy-boolean.cov-map
@ -13,6 +13,7 @@ Number of file 0 mappings: 6
    false = (c1 - c2)
 - Code(Counter(2)) at (prev + 0, 18) to (start + 0, 19)
 - Code(Counter(1)) at (prev + 1, 5) to (start + 1, 2)
+Highest counter ID seen: c2

 Function name: lazy_boolean::branch_or
 Raw bytes (38): 0x[01, 01, 01, 05, 09, 06, 01, 1b, 01, 01, 10, 05, 04, 09, 00, 0a, 05, 00, 0d, 00, 0e, 20, 09, 02, 00, 0d, 00, 0e, 02, 00, 12, 00, 13, 05, 01, 05, 01, 02]
@ -30,6 +31,7 @@ Number of file 0 mappings: 6
 - Code(Expression(0, Sub)) at (prev + 0, 18) to (start + 0, 19)
    = (c1 - c2)
 - Code(Counter(1)) at (prev + 1, 5) to (start + 1, 2)
+Highest counter ID seen: c2

 Function name: lazy_boolean::chain
 Raw bytes (149): 0x[01, 01, 13, 11, 07, 0b, 16, 15, 1a, 09, 0d, 05, 09, 05, 09, 09, 0d, 47, 25, 4b, 21, 19, 1d, 03, 19, 03, 19, 3e, 1d, 03, 19, 3e, 1d, 03, 19, 47, 25, 4b, 21, 19, 1d, 13, 01, 24, 01, 01, 10, 03, 04, 09, 00, 0a, 05, 00, 0d, 00, 12, 20, 09, 16, 00, 0d, 00, 12, 09, 00, 16, 00, 1b, 20, 0d, 1a, 00, 16, 00, 1b, 0d, 00, 1f, 00, 24, 20, 11, 15, 00, 1f, 00, 24, 11, 00, 28, 00, 2d, 03, 01, 05, 00, 11, 43, 03, 09, 00, 0a, 03, 00, 0d, 00, 12, 20, 19, 3e, 00, 0d, 00, 12, 3e, 00, 16, 00, 1b, 20, 1d, 3a, 00, 16, 00, 1b, 3a, 00, 1f, 00, 24, 20, 21, 25, 00, 1f, 00, 24, 25, 00, 28, 00, 2d, 43, 01, 05, 01, 02]
@ -94,6 +96,7 @@ Number of file 0 mappings: 19
 - Code(Counter(9)) at (prev + 0, 40) to (start + 0, 45)
 - Code(Expression(16, Add)) at (prev + 1, 5) to (start + 1, 2)
    = (((c6 + c7) + c8) + c9)
+Highest counter ID seen: c9

 Function name: lazy_boolean::nested_mixed
 Raw bytes (155): 0x[01, 01, 16, 33, 1a, 09, 0d, 1e, 0d, 05, 09, 05, 09, 05, 09, 1e, 0d, 05, 09, 09, 0d, 33, 11, 09, 0d, 33, 11, 09, 0d, 19, 57, 1d, 21, 03, 15, 15, 19, 4a, 4e, 15, 19, 03, 15, 19, 57, 1d, 21, 13, 01, 31, 01, 01, 10, 03, 04, 09, 00, 0a, 05, 00, 0e, 00, 13, 20, 09, 1e, 00, 0e, 00, 13, 1e, 00, 17, 00, 1d, 20, 0d, 1a, 00, 17, 00, 1d, 33, 00, 23, 00, 28, 20, 11, 2e, 00, 23, 00, 28, 2e, 00, 2c, 00, 33, 03, 01, 05, 00, 11, 53, 03, 09, 00, 0a, 03, 00, 0e, 00, 13, 20, 15, 4e, 00, 0e, 00, 13, 15, 00, 17, 00, 1c, 20, 19, 4a, 00, 17, 00, 1c, 47, 00, 22, 00, 28, 20, 1d, 21, 00, 22, 00, 28, 1d, 00, 2c, 00, 33, 53, 01, 05, 01, 02]
@ -163,4 +166,5 @@ Number of file 0 mappings: 19
 - Code(Counter(7)) at (prev + 0, 44) to (start + 0, 51)
 - Code(Expression(20, Add)) at (prev + 1, 5) to (start + 1, 2)
    = (c6 + (c7 + c8))
+Highest counter ID seen: c8

--- a/tests/coverage/branch/let-else.cov-map
+++ b/tests/coverage/branch/let-else.cov-map
@ -16,4 +16,5 @@ Number of file 0 mappings: 7
 - Code(Expression(0, Sub)) at (prev + 4, 5) to (start + 0, 11)
    = (c1 - c2)
 - Code(Counter(1)) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: c2

--- a/tests/coverage/branch/match-arms.cov-map
+++ b/tests/coverage/branch/match-arms.cov-map
@ -34,6 +34,7 @@ Number of file 0 mappings: 12
    = ((((Zero + c2) + c3) + c4) + c5)
 - Code(Expression(4, Add)) at (prev + 3, 5) to (start + 1, 2)
    = ((((((((Zero + c2) + c3) + c4) + c5) + c6) + c7) + c8) + c9)
+Highest counter ID seen: c10

 Function name: match_arms::match_arms
 Raw bytes (51): 0x[01, 01, 06, 05, 07, 0b, 11, 09, 0d, 13, 02, 17, 09, 11, 0d, 07, 01, 18, 01, 01, 10, 05, 03, 0b, 00, 10, 11, 01, 11, 00, 21, 0d, 01, 11, 00, 21, 09, 01, 11, 00, 21, 02, 01, 11, 00, 21, 0f, 03, 05, 01, 02]
@ -56,6 +57,7 @@ Number of file 0 mappings: 7
    = (c1 - ((c2 + c3) + c4))
 - Code(Expression(3, Add)) at (prev + 3, 5) to (start + 1, 2)
    = (((c4 + c3) + c2) + (c1 - ((c2 + c3) + c4)))
+Highest counter ID seen: c4

 Function name: match_arms::or_patterns
 Raw bytes (75): 0x[01, 01, 0d, 11, 0d, 05, 2f, 33, 11, 09, 0d, 09, 2a, 05, 2f, 33, 11, 09, 0d, 03, 27, 09, 2a, 05, 2f, 33, 11, 09, 0d, 09, 01, 25, 01, 01, 10, 05, 03, 0b, 00, 10, 11, 01, 11, 00, 12, 0d, 00, 1e, 00, 1f, 03, 00, 24, 00, 2e, 09, 01, 11, 00, 12, 2a, 00, 1e, 00, 1f, 27, 00, 24, 00, 2e, 23, 03, 05, 01, 02]
@ -89,4 +91,5 @@ Number of file 0 mappings: 9
    = (c2 + (c1 - ((c2 + c3) + c4)))
 - Code(Expression(8, Add)) at (prev + 3, 5) to (start + 1, 2)
    = ((c4 + c3) + (c2 + (c1 - ((c2 + c3) + c4))))
+Highest counter ID seen: c4

--- a/tests/coverage/branch/match-trivial.cov-map
+++ b/tests/coverage/branch/match-trivial.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 22, 1) to (start + 1, 16)
+Highest counter ID seen: (none)

 Function name: match_trivial::trivial
 Raw bytes (14): 0x[01, 01, 00, 02, 01, 1e, 01, 01, 10, 05, 03, 0b, 05, 02]
@ -14,4 +15,5 @@ Number of expressions: 0
 Number of file 0 mappings: 2
 - Code(Counter(0)) at (prev + 30, 1) to (start + 1, 16)
 - Code(Counter(1)) at (prev + 3, 11) to (start + 5, 2)
+Highest counter ID seen: c1

--- a/tests/coverage/branch/no-mir-spans.cov-map
+++ b/tests/coverage/branch/no-mir-spans.cov-map
@ -8,6 +8,7 @@ Number of file 0 mappings: 2
 - Branch { true: Counter(1), false: Counter(2) } at (prev + 4, 11) to (start + 0, 16)
    true  = c1
    false = c2
+Highest counter ID seen: c2

 Function name: no_mir_spans::while_cond_not
 Raw bytes (16): 0x[01, 01, 00, 02, 01, 19, 01, 00, 15, 20, 09, 05, 04, 0b, 00, 14]
@ -19,6 +20,7 @@ Number of file 0 mappings: 2
 - Branch { true: Counter(2), false: Counter(1) } at (prev + 4, 11) to (start + 0, 20)
    true  = c2
    false = c1
+Highest counter ID seen: c2

 Function name: no_mir_spans::while_op_and
 Raw bytes (25): 0x[01, 01, 01, 09, 0d, 03, 01, 22, 01, 00, 13, 20, 09, 05, 05, 0b, 00, 10, 20, 02, 0d, 00, 14, 00, 19]
@ -34,6 +36,7 @@ Number of file 0 mappings: 3
 - Branch { true: Expression(0, Sub), false: Counter(3) } at (prev + 0, 20) to (start + 0, 25)
    true  = (c2 - c3)
    false = c3
+Highest counter ID seen: c3

 Function name: no_mir_spans::while_op_or
 Raw bytes (25): 0x[01, 01, 01, 09, 0d, 03, 01, 2d, 01, 00, 12, 20, 05, 09, 05, 0b, 00, 10, 20, 0d, 02, 00, 14, 00, 19]
@ -49,4 +52,5 @@ Number of file 0 mappings: 3
 - Branch { true: Counter(3), false: Expression(0, Sub) } at (prev + 0, 20) to (start + 0, 25)
    true  = c3
    false = (c2 - c3)
+Highest counter ID seen: c3

--- a/tests/coverage/branch/while.cov-map
+++ b/tests/coverage/branch/while.cov-map
@ -14,6 +14,7 @@ Number of file 0 mappings: 6
    false = c1
 - Code(Counter(2)) at (prev + 0, 17) to (start + 2, 6)
 - Code(Counter(1)) at (prev + 3, 1) to (start + 0, 2)
+Highest counter ID seen: c2

 Function name: while::while_cond_not
 Raw bytes (38): 0x[01, 01, 01, 05, 09, 06, 01, 15, 01, 01, 10, 05, 03, 09, 00, 12, 03, 01, 0b, 00, 14, 20, 09, 05, 00, 0b, 00, 14, 09, 00, 15, 02, 06, 05, 03, 01, 00, 02]
@ -31,6 +32,7 @@ Number of file 0 mappings: 6
    false = c1
 - Code(Counter(2)) at (prev + 0, 21) to (start + 2, 6)
 - Code(Counter(1)) at (prev + 3, 1) to (start + 0, 2)
+Highest counter ID seen: c2

 Function name: while::while_op_and
 Raw bytes (56): 0x[01, 01, 04, 05, 09, 03, 0d, 03, 0d, 11, 0d, 08, 01, 1e, 01, 01, 10, 05, 03, 09, 01, 12, 03, 02, 0b, 00, 10, 20, 0a, 0d, 00, 0b, 00, 10, 0a, 00, 14, 00, 19, 20, 09, 11, 00, 14, 00, 19, 09, 00, 1a, 03, 06, 0f, 04, 01, 00, 02]
@ -57,6 +59,7 @@ Number of file 0 mappings: 8
 - Code(Counter(2)) at (prev + 0, 26) to (start + 3, 6)
 - Code(Expression(3, Add)) at (prev + 4, 1) to (start + 0, 2)
    = (c4 + c3)
+Highest counter ID seen: c4

 Function name: while::while_op_or
 Raw bytes (66): 0x[01, 01, 09, 05, 1b, 09, 0d, 03, 09, 03, 09, 22, 0d, 03, 09, 09, 0d, 22, 0d, 03, 09, 08, 01, 29, 01, 01, 10, 05, 03, 09, 01, 12, 03, 02, 0b, 00, 10, 20, 09, 22, 00, 0b, 00, 10, 22, 00, 14, 00, 19, 20, 0d, 1e, 00, 14, 00, 19, 1b, 00, 1a, 03, 06, 1e, 04, 01, 00, 02]
@ -89,4 +92,5 @@ Number of file 0 mappings: 8
    = (c2 + c3)
 - Code(Expression(7, Sub)) at (prev + 4, 1) to (start + 0, 2)
    = (((c1 + (c2 + c3)) - c2) - c3)
+Highest counter ID seen: c3

--- a/tests/coverage/closure.cov-map
+++ b/tests/coverage/closure.cov-map
@ -30,6 +30,7 @@ Number of file 0 mappings: 24
 - Code(Expression(0, Sub)) at (prev + 4, 6) to (start + 0, 7)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 1, 5) to (start + 3, 2)
+Highest counter ID seen: c1

 Function name: closure::main::{closure#0}
 Raw bytes (26): 0x[01, 01, 01, 01, 05, 04, 01, 28, 05, 02, 14, 05, 02, 15, 02, 0a, 02, 02, 0a, 00, 0b, 01, 01, 09, 01, 06]
@ -43,6 +44,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 2, 10) to (start + 0, 11)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 1, 9) to (start + 1, 6)
+Highest counter ID seen: c1

 Function name: closure::main::{closure#10} (unused)
 Raw bytes (10): 0x[01, 01, 00, 01, 00, 9b, 01, 07, 00, 21]
@ -51,6 +53,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 155, 7) to (start + 0, 33)
+Highest counter ID seen: (none)

 Function name: closure::main::{closure#11} (unused)
 Raw bytes (10): 0x[01, 01, 00, 01, 00, 9f, 01, 07, 00, 21]
@ -59,6 +62,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 159, 7) to (start + 0, 33)
+Highest counter ID seen: (none)

 Function name: closure::main::{closure#12} (unused)
 Raw bytes (10): 0x[01, 01, 00, 01, 00, a7, 01, 01, 00, 17]
@ -67,6 +71,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 167, 1) to (start + 0, 23)
+Highest counter ID seen: (none)

 Function name: closure::main::{closure#13} (unused)
 Raw bytes (10): 0x[01, 01, 00, 01, 00, ac, 01, 0d, 02, 0e]
@ -75,6 +80,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 172, 13) to (start + 2, 14)
+Highest counter ID seen: (none)

 Function name: closure::main::{closure#14}
 Raw bytes (27): 0x[01, 01, 01, 01, 05, 04, 01, b3, 01, 0d, 02, 1b, 05, 02, 1e, 00, 25, 02, 00, 2f, 00, 33, 01, 01, 0d, 00, 0e]
@ -88,6 +94,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 0, 47) to (start + 0, 51)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 1, 13) to (start + 0, 14)
+Highest counter ID seen: c1

 Function name: closure::main::{closure#15}
 Raw bytes (37): 0x[01, 01, 01, 01, 05, 06, 01, bb, 01, 09, 00, 0a, 01, 01, 0d, 00, 15, 01, 01, 11, 01, 1b, 05, 01, 1e, 00, 25, 02, 00, 2f, 00, 33, 01, 02, 09, 00, 0a]
@ -103,6 +110,7 @@ Number of file 0 mappings: 6
 - Code(Expression(0, Sub)) at (prev + 0, 47) to (start + 0, 51)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 2, 9) to (start + 0, 10)
+Highest counter ID seen: c1

 Function name: closure::main::{closure#16}
 Raw bytes (27): 0x[01, 01, 01, 01, 05, 04, 01, c5, 01, 0d, 02, 1b, 05, 02, 1e, 00, 25, 02, 00, 2f, 00, 33, 01, 01, 0d, 00, 0e]
@ -116,6 +124,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 0, 47) to (start + 0, 51)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 1, 13) to (start + 0, 14)
+Highest counter ID seen: c1

 Function name: closure::main::{closure#17}
 Raw bytes (37): 0x[01, 01, 01, 01, 05, 06, 01, cd, 01, 09, 00, 0a, 01, 01, 0d, 00, 15, 01, 01, 11, 01, 1b, 05, 01, 1e, 00, 25, 02, 00, 2f, 00, 33, 01, 02, 09, 00, 0a]
@ -131,6 +140,7 @@ Number of file 0 mappings: 6
 - Code(Expression(0, Sub)) at (prev + 0, 47) to (start + 0, 51)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 2, 9) to (start + 0, 10)
+Highest counter ID seen: c1

 Function name: closure::main::{closure#18} (unused)
 Raw bytes (24): 0x[01, 01, 00, 04, 00, 19, 0d, 02, 1c, 00, 02, 1d, 02, 12, 00, 02, 12, 00, 13, 00, 01, 11, 01, 0e]
@ -142,6 +152,7 @@ Number of file 0 mappings: 4
 - Code(Zero) at (prev + 2, 29) to (start + 2, 18)
 - Code(Zero) at (prev + 2, 18) to (start + 0, 19)
 - Code(Zero) at (prev + 1, 17) to (start + 1, 14)
+Highest counter ID seen: (none)

 Function name: closure::main::{closure#19}
 Raw bytes (26): 0x[01, 01, 01, 01, 05, 04, 01, 43, 0d, 02, 1c, 05, 02, 1d, 02, 12, 02, 02, 12, 00, 13, 01, 01, 11, 01, 0e]
@ -155,6 +166,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 2, 18) to (start + 0, 19)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 1, 17) to (start + 1, 14)
+Highest counter ID seen: c1

 Function name: closure::main::{closure#1}
 Raw bytes (26): 0x[01, 01, 01, 01, 05, 04, 01, 52, 05, 02, 14, 05, 02, 15, 02, 0a, 02, 02, 0a, 00, 0b, 01, 01, 09, 01, 06]
@ -168,6 +180,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 2, 10) to (start + 0, 11)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 1, 9) to (start + 1, 6)
+Highest counter ID seen: c1

 Function name: closure::main::{closure#2}
 Raw bytes (26): 0x[01, 01, 01, 01, 05, 04, 01, 68, 05, 02, 14, 05, 02, 15, 02, 0a, 02, 02, 0a, 00, 0b, 01, 01, 09, 01, 06]
@ -181,6 +194,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 2, 10) to (start + 0, 11)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 1, 9) to (start + 1, 6)
+Highest counter ID seen: c1

 Function name: closure::main::{closure#3} (unused)
 Raw bytes (25): 0x[01, 01, 00, 04, 00, 81, 01, 05, 01, 14, 00, 01, 15, 02, 0a, 00, 02, 0a, 00, 0b, 00, 01, 09, 01, 06]
@ -192,6 +206,7 @@ Number of file 0 mappings: 4
 - Code(Zero) at (prev + 1, 21) to (start + 2, 10)
 - Code(Zero) at (prev + 2, 10) to (start + 0, 11)
 - Code(Zero) at (prev + 1, 9) to (start + 1, 6)
+Highest counter ID seen: (none)

 Function name: closure::main::{closure#4} (unused)
 Raw bytes (10): 0x[01, 01, 00, 01, 00, 89, 01, 35, 00, 43]
@ -200,6 +215,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 137, 53) to (start + 0, 67)
+Highest counter ID seen: (none)

 Function name: closure::main::{closure#5}
 Raw bytes (10): 0x[01, 01, 00, 01, 01, 8c, 01, 3d, 00, 4f]
@ -208,6 +224,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 140, 61) to (start + 0, 79)
+Highest counter ID seen: c0

 Function name: closure::main::{closure#6}
 Raw bytes (10): 0x[01, 01, 00, 01, 01, 8d, 01, 41, 00, 57]
@ -216,6 +233,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 141, 65) to (start + 0, 87)
+Highest counter ID seen: c0

 Function name: closure::main::{closure#7} (unused)
 Raw bytes (10): 0x[01, 01, 00, 01, 00, 8e, 01, 3b, 00, 51]
@ -224,6 +242,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 142, 59) to (start + 0, 81)
+Highest counter ID seen: (none)

 Function name: closure::main::{closure#8} (unused)
 Raw bytes (10): 0x[01, 01, 00, 01, 00, 93, 01, 3b, 00, 55]
@ -232,6 +251,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 147, 59) to (start + 0, 85)
+Highest counter ID seen: (none)

 Function name: closure::main::{closure#9} (unused)
 Raw bytes (10): 0x[01, 01, 00, 01, 00, 95, 01, 38, 02, 06]
@ -240,4 +260,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 149, 56) to (start + 2, 6)
+Highest counter ID seen: (none)

--- a/tests/coverage/closure_bug.cov-map
+++ b/tests/coverage/closure_bug.cov-map
@ -29,6 +29,7 @@ Number of file 0 mappings: 17
 - Code(Expression(3, Sub)) at (prev + 0, 23) to (start + 0, 24)
    = (c0 - c4)
 - Code(Counter(0)) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: c4

 Function name: closure_bug::main::{closure#0}
 Raw bytes (26): 0x[01, 01, 01, 01, 05, 04, 01, 0e, 09, 00, 12, 05, 00, 15, 00, 19, 02, 00, 23, 00, 28, 01, 00, 29, 00, 2a]
@ -42,6 +43,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 0, 35) to (start + 0, 40)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 0, 41) to (start + 0, 42)
+Highest counter ID seen: c1

 Function name: closure_bug::main::{closure#1}
 Raw bytes (26): 0x[01, 01, 01, 01, 05, 04, 01, 17, 09, 00, 12, 05, 00, 15, 00, 19, 02, 00, 23, 00, 28, 01, 00, 29, 00, 2a]
@ -55,6 +57,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 0, 35) to (start + 0, 40)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 0, 41) to (start + 0, 42)
+Highest counter ID seen: c1

 Function name: closure_bug::main::{closure#2}
 Raw bytes (26): 0x[01, 01, 01, 01, 05, 04, 01, 20, 09, 00, 12, 05, 00, 15, 00, 19, 02, 00, 23, 00, 28, 01, 00, 29, 00, 2a]
@ -68,6 +71,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 0, 35) to (start + 0, 40)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 0, 41) to (start + 0, 42)
+Highest counter ID seen: c1

 Function name: closure_bug::main::{closure#3}
 Raw bytes (26): 0x[01, 01, 01, 01, 05, 04, 01, 29, 09, 00, 12, 05, 00, 15, 00, 19, 02, 00, 23, 00, 28, 01, 00, 29, 00, 2a]
@ -81,4 +85,5 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 0, 35) to (start + 0, 40)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 0, 41) to (start + 0, 42)
+Highest counter ID seen: c1

--- a/tests/coverage/closure_macro.cov-map
+++ b/tests/coverage/closure_macro.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 29, 1) to (start + 2, 2)
+Highest counter ID seen: c0

 Function name: closure_macro::main
 Raw bytes (36): 0x[01, 01, 01, 01, 05, 06, 01, 21, 01, 01, 21, 02, 02, 09, 00, 0f, 01, 00, 12, 00, 54, 05, 00, 54, 00, 55, 02, 02, 09, 02, 0b, 01, 03, 01, 00, 02]
@ -21,6 +22,7 @@ Number of file 0 mappings: 6
 - Code(Expression(0, Sub)) at (prev + 2, 9) to (start + 2, 11)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 3, 1) to (start + 0, 2)
+Highest counter ID seen: c1

 Function name: closure_macro::main::{closure#0}
 Raw bytes (35): 0x[01, 01, 03, 01, 05, 05, 0b, 09, 0d, 05, 01, 10, 1c, 03, 21, 05, 04, 11, 01, 27, 02, 03, 11, 00, 16, 0d, 00, 17, 00, 1e, 07, 02, 09, 00, 0a]
@ -38,4 +40,5 @@ Number of file 0 mappings: 5
 - Code(Counter(3)) at (prev + 0, 23) to (start + 0, 30)
 - Code(Expression(1, Add)) at (prev + 2, 9) to (start + 0, 10)
    = (c1 + (c2 + c3))
+Highest counter ID seen: c3

--- a/tests/coverage/closure_macro_async.cov-map
+++ b/tests/coverage/closure_macro_async.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 34, 1) to (start + 2, 2)
+Highest counter ID seen: c0

 Function name: closure_macro_async::test
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 26, 01, 00, 2b]
@ -13,6 +14,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 38, 1) to (start + 0, 43)
+Highest counter ID seen: c0

 Function name: closure_macro_async::test::{closure#0}
 Raw bytes (36): 0x[01, 01, 01, 01, 05, 06, 01, 26, 2b, 01, 21, 02, 02, 09, 00, 0f, 01, 00, 12, 00, 54, 05, 00, 54, 00, 55, 02, 02, 09, 02, 0b, 01, 03, 01, 00, 02]
@ -29,6 +31,7 @@ Number of file 0 mappings: 6
 - Code(Expression(0, Sub)) at (prev + 2, 9) to (start + 2, 11)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 3, 1) to (start + 0, 2)
+Highest counter ID seen: c1

 Function name: closure_macro_async::test::{closure#0}::{closure#0}
 Raw bytes (35): 0x[01, 01, 03, 01, 05, 05, 0b, 09, 0d, 05, 01, 15, 1c, 03, 21, 05, 04, 11, 01, 27, 02, 03, 11, 00, 16, 0d, 00, 17, 00, 1e, 07, 02, 09, 00, 0a]
@ -46,4 +49,5 @@ Number of file 0 mappings: 5
 - Code(Counter(3)) at (prev + 0, 23) to (start + 0, 30)
 - Code(Expression(1, Add)) at (prev + 2, 9) to (start + 0, 10)
    = (c1 + (c2 + c3))
+Highest counter ID seen: c3

--- a/tests/coverage/closure_unit_return.cov-map
+++ b/tests/coverage/closure_unit_return.cov-map
@ -6,6 +6,7 @@ Number of expressions: 0
 Number of file 0 mappings: 2
 - Code(Counter(0)) at (prev + 7, 1) to (start + 1, 16)
 - Code(Counter(0)) at (prev + 5, 5) to (start + 2, 2)
+Highest counter ID seen: c0

 Function name: closure_unit_return::explicit_unit::{closure#0} (unused)
 Raw bytes (9): 0x[01, 01, 00, 01, 00, 08, 16, 02, 06]
@ -14,6 +15,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 8, 22) to (start + 2, 6)
+Highest counter ID seen: (none)

 Function name: closure_unit_return::implicit_unit
 Raw bytes (14): 0x[01, 01, 00, 02, 01, 10, 01, 01, 10, 01, 05, 05, 02, 02]
@ -23,6 +25,7 @@ Number of expressions: 0
 Number of file 0 mappings: 2
 - Code(Counter(0)) at (prev + 16, 1) to (start + 1, 16)
 - Code(Counter(0)) at (prev + 5, 5) to (start + 2, 2)
+Highest counter ID seen: c0

 Function name: closure_unit_return::implicit_unit::{closure#0} (unused)
 Raw bytes (9): 0x[01, 01, 00, 01, 00, 11, 16, 02, 06]
@ -31,4 +34,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 17, 22) to (start + 2, 6)
+Highest counter ID seen: (none)

--- a/tests/coverage/condition/conditions.cov-map
+++ b/tests/coverage/condition/conditions.cov-map
@ -29,6 +29,7 @@ Number of file 0 mappings: 9
    false = c4
 - Code(Expression(0, Add)) at (prev + 1, 5) to (start + 1, 2)
    = ((c2 + c3) + c4)
+Highest counter ID seen: c4

 Function name: conditions::assign_3_or_and
 Raw bytes (73): 0x[01, 01, 09, 05, 07, 0b, 11, 09, 0d, 01, 05, 01, 05, 22, 11, 01, 05, 22, 11, 01, 05, 09, 01, 17, 01, 00, 2f, 03, 01, 09, 00, 0a, 01, 00, 0d, 00, 0e, 20, 05, 22, 00, 0d, 00, 0e, 22, 00, 12, 00, 13, 20, 1e, 11, 00, 12, 00, 13, 1e, 00, 17, 00, 18, 20, 09, 0d, 00, 17, 00, 18, 03, 01, 05, 01, 02]
@ -64,6 +65,7 @@ Number of file 0 mappings: 9
    false = c3
 - Code(Expression(0, Add)) at (prev + 1, 5) to (start + 1, 2)
    = (c1 + ((c2 + c3) + c4))
+Highest counter ID seen: c4

 Function name: conditions::assign_and
 Raw bytes (51): 0x[01, 01, 04, 07, 0e, 09, 0d, 01, 05, 01, 05, 07, 01, 0d, 01, 00, 21, 03, 01, 09, 00, 0a, 01, 00, 0d, 00, 0e, 20, 05, 0e, 00, 0d, 00, 0e, 05, 00, 12, 00, 13, 20, 09, 0d, 00, 12, 00, 13, 03, 01, 05, 01, 02]
@ -88,6 +90,7 @@ Number of file 0 mappings: 7
    false = c3
 - Code(Expression(0, Add)) at (prev + 1, 5) to (start + 1, 2)
    = ((c2 + c3) + (c0 - c1))
+Highest counter ID seen: c3

 Function name: conditions::assign_or
 Raw bytes (51): 0x[01, 01, 04, 07, 0d, 05, 09, 01, 05, 01, 05, 07, 01, 12, 01, 00, 20, 03, 01, 09, 00, 0a, 01, 00, 0d, 00, 0e, 20, 05, 0e, 00, 0d, 00, 0e, 0e, 00, 12, 00, 13, 20, 09, 0d, 00, 12, 00, 13, 03, 01, 05, 01, 02]
@ -113,6 +116,7 @@ Number of file 0 mappings: 7
    false = c3
 - Code(Expression(0, Add)) at (prev + 1, 5) to (start + 1, 2)
    = ((c1 + c2) + c3)
+Highest counter ID seen: c3

 Function name: conditions::foo
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 21, 01, 02, 02]
@ -121,6 +125,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 33, 1) to (start + 2, 2)
+Highest counter ID seen: c0

 Function name: conditions::func_call
 Raw bytes (39): 0x[01, 01, 03, 01, 05, 0b, 02, 09, 0d, 05, 01, 25, 01, 01, 0a, 20, 05, 02, 01, 09, 00, 0a, 05, 00, 0e, 00, 0f, 20, 09, 0d, 00, 0e, 00, 0f, 07, 01, 01, 00, 02]
@ -141,6 +146,7 @@ Number of file 0 mappings: 5
    false = c3
 - Code(Expression(1, Add)) at (prev + 1, 1) to (start + 0, 2)
    = ((c2 + c3) + (c0 - c1))
+Highest counter ID seen: c3

 Function name: conditions::simple_assign
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 08, 01, 03, 02]
@ -149,4 +155,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 8, 1) to (start + 3, 2)
+Highest counter ID seen: c0

--- a/tests/coverage/conditions.cov-map
+++ b/tests/coverage/conditions.cov-map
@ -260,4 +260,5 @@ Number of file 0 mappings: 68
 - Code(Counter(9)) at (prev + 2, 9) to (start + 0, 15)
 - Code(Expression(137, Add)) at (prev + 2, 1) to (start + 0, 2)
    = ((c4 + (((c5 + c6) + c7) + c8)) + ((((c9 + c10) + c11) + c12) + ((c0 - c2) - c3)))
+Highest counter ID seen: c35

--- a/tests/coverage/continue.cov-map
+++ b/tests/coverage/continue.cov-map
@ -76,4 +76,5 @@ Number of file 0 mappings: 30
 - Code(Counter(16)) at (prev + 3, 9) to (start + 0, 14)
 - Code(Expression(27, Add)) at (prev + 2, 13) to (start + 1, 2)
    = (c18 + c17)
+Highest counter ID seen: c18

--- a/tests/coverage/coroutine.cov-map
+++ b/tests/coverage/coroutine.cov-map
@ -10,6 +10,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 2, 9) to (start + 0, 40)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 2, 1) to (start + 0, 2)
+Highest counter ID seen: c1

 Function name: coroutine::main
 Raw bytes (65): 0x[01, 01, 08, 07, 0d, 05, 09, 11, 15, 1e, 19, 11, 15, 15, 19, 1e, 19, 11, 15, 09, 01, 13, 01, 02, 16, 01, 08, 0b, 00, 2e, 11, 01, 2b, 00, 2d, 03, 01, 0e, 00, 35, 11, 02, 0b, 00, 2e, 1e, 01, 22, 00, 27, 1a, 00, 2c, 00, 2e, 17, 01, 0e, 00, 35, 1a, 02, 01, 00, 02]
@ -39,6 +40,7 @@ Number of file 0 mappings: 9
    = (c5 + c6)
 - Code(Expression(6, Sub)) at (prev + 2, 1) to (start + 0, 2)
    = ((c4 - c5) - c6)
+Highest counter ID seen: c4

 Function name: coroutine::main::{closure#0}
 Raw bytes (14): 0x[01, 01, 00, 02, 01, 16, 08, 01, 1f, 05, 02, 10, 01, 06]
@ -48,4 +50,5 @@ Number of expressions: 0
 Number of file 0 mappings: 2
 - Code(Counter(0)) at (prev + 22, 8) to (start + 1, 31)
 - Code(Counter(1)) at (prev + 2, 16) to (start + 1, 6)
+Highest counter ID seen: c1

--- a/tests/coverage/coverage_attr_closure.cov-map
+++ b/tests/coverage/coverage_attr_closure.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 6, 15) to (start + 2, 2)
+Highest counter ID seen: c0

 Function name: coverage_attr_closure::contains_closures_off::{closure#0} (unused)
 Raw bytes (9): 0x[01, 01, 00, 01, 00, 1d, 13, 02, 06]
@ -13,6 +14,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 29, 19) to (start + 2, 6)
+Highest counter ID seen: (none)

 Function name: coverage_attr_closure::contains_closures_on
 Raw bytes (19): 0x[01, 01, 00, 03, 01, 0f, 01, 01, 1a, 01, 05, 09, 00, 1b, 01, 04, 01, 00, 02]
@ -23,6 +25,7 @@ Number of file 0 mappings: 3
 - Code(Counter(0)) at (prev + 15, 1) to (start + 1, 26)
 - Code(Counter(0)) at (prev + 5, 9) to (start + 0, 27)
 - Code(Counter(0)) at (prev + 4, 1) to (start + 0, 2)
+Highest counter ID seen: c0

 Function name: coverage_attr_closure::contains_closures_on::{closure#0} (unused)
 Raw bytes (9): 0x[01, 01, 00, 01, 00, 11, 13, 02, 06]
@ -31,4 +34,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 17, 19) to (start + 2, 6)
+Highest counter ID seen: (none)

--- a/tests/coverage/dead_code.cov-map
+++ b/tests/coverage/dead_code.cov-map
@ -10,6 +10,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 2, 6) to (start + 0, 7)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: c1

 Function name: dead_code::unused_fn (unused)
 Raw bytes (24): 0x[01, 01, 00, 04, 00, 0f, 01, 07, 0f, 00, 07, 10, 02, 06, 00, 02, 06, 00, 07, 00, 01, 01, 00, 02]
@ -21,6 +22,7 @@ Number of file 0 mappings: 4
 - Code(Zero) at (prev + 7, 16) to (start + 2, 6)
 - Code(Zero) at (prev + 2, 6) to (start + 0, 7)
 - Code(Zero) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: (none)

 Function name: dead_code::unused_pub_fn_not_in_library (unused)
 Raw bytes (24): 0x[01, 01, 00, 04, 00, 03, 01, 07, 0f, 00, 07, 10, 02, 06, 00, 02, 06, 00, 07, 00, 01, 01, 00, 02]
@ -32,4 +34,5 @@ Number of file 0 mappings: 4
 - Code(Zero) at (prev + 7, 16) to (start + 2, 6)
 - Code(Zero) at (prev + 2, 6) to (start + 0, 7)
 - Code(Zero) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: (none)

--- a/tests/coverage/drop_trait.cov-map
+++ b/tests/coverage/drop_trait.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 9, 5) to (start + 2, 6)
+Highest counter ID seen: c0

 Function name: drop_trait::main
 Raw bytes (24): 0x[01, 01, 00, 04, 01, 0e, 01, 05, 0c, 05, 06, 09, 01, 16, 00, 02, 06, 04, 0b, 01, 05, 01, 00, 02]
@ -16,4 +17,5 @@ Number of file 0 mappings: 4
 - Code(Counter(1)) at (prev + 6, 9) to (start + 1, 22)
 - Code(Zero) at (prev + 2, 6) to (start + 4, 11)
 - Code(Counter(0)) at (prev + 5, 1) to (start + 0, 2)
+Highest counter ID seen: c1

--- a/tests/coverage/fn_sig_into_try.cov-map
+++ b/tests/coverage/fn_sig_into_try.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 10, 1) to (start + 5, 2)
+Highest counter ID seen: c0

 Function name: fn_sig_into_try::b
 Raw bytes (26): 0x[01, 01, 01, 01, 00, 04, 01, 11, 01, 03, 0f, 00, 03, 0f, 00, 10, 02, 01, 05, 00, 0c, 01, 01, 01, 00, 02]
@ -18,6 +19,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 1, 5) to (start + 0, 12)
    = (c0 - Zero)
 - Code(Counter(0)) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: c0

 Function name: fn_sig_into_try::c
 Raw bytes (26): 0x[01, 01, 01, 01, 00, 04, 01, 18, 01, 03, 17, 00, 03, 17, 00, 18, 02, 01, 05, 00, 0c, 01, 01, 01, 00, 02]
@ -31,6 +33,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 1, 5) to (start + 0, 12)
    = (c0 - Zero)
 - Code(Counter(0)) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: c0

 Function name: fn_sig_into_try::d
 Raw bytes (26): 0x[01, 01, 01, 01, 00, 04, 01, 1f, 01, 04, 0f, 00, 04, 0f, 00, 10, 02, 01, 05, 00, 0c, 01, 01, 01, 00, 02]
@ -44,4 +47,5 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 1, 5) to (start + 0, 12)
    = (c0 - Zero)
 - Code(Counter(0)) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: c0

--- a/tests/coverage/generics.cov-map
+++ b/tests/coverage/generics.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 17, 5) to (start + 2, 6)
+Highest counter ID seen: c0

 Function name: <generics::Firework<f64>>::set_strength
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 0a, 05, 02, 06]
@ -13,6 +14,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 10, 5) to (start + 2, 6)
+Highest counter ID seen: c0

 Function name: <generics::Firework<i32> as core::ops::drop::Drop>::drop
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 11, 05, 02, 06]
@ -21,6 +23,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 17, 5) to (start + 2, 6)
+Highest counter ID seen: c0

 Function name: <generics::Firework<i32>>::set_strength
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 0a, 05, 02, 06]
@ -29,6 +32,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 10, 5) to (start + 2, 6)
+Highest counter ID seen: c0

 Function name: generics::main
 Raw bytes (24): 0x[01, 01, 00, 04, 01, 16, 01, 08, 0c, 05, 09, 09, 01, 16, 00, 02, 06, 04, 0b, 01, 05, 01, 00, 02]
@ -40,4 +44,5 @@ Number of file 0 mappings: 4
 - Code(Counter(1)) at (prev + 9, 9) to (start + 1, 22)
 - Code(Zero) at (prev + 2, 6) to (start + 4, 11)
 - Code(Counter(0)) at (prev + 5, 1) to (start + 0, 2)
+Highest counter ID seen: c1

--- a/tests/coverage/holes.cov-map
+++ b/tests/coverage/holes.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 37, 9) to (start + 0, 29)
+Highest counter ID seen: (none)

 Function name: holes::main
 Raw bytes (44): 0x[01, 01, 00, 08, 01, 08, 01, 06, 11, 01, 0f, 05, 00, 12, 01, 04, 05, 00, 12, 01, 07, 05, 00, 12, 01, 06, 05, 00, 12, 01, 06, 05, 03, 0f, 01, 0a, 05, 03, 0f, 01, 0a, 05, 01, 02]
@ -20,6 +21,7 @@ Number of file 0 mappings: 8
 - Code(Counter(0)) at (prev + 6, 5) to (start + 3, 15)
 - Code(Counter(0)) at (prev + 10, 5) to (start + 3, 15)
 - Code(Counter(0)) at (prev + 10, 5) to (start + 1, 2)
+Highest counter ID seen: c0

 Function name: holes::main::_unused_fn (unused)
 Raw bytes (9): 0x[01, 01, 00, 01, 00, 19, 05, 00, 17]
@ -28,6 +30,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 25, 5) to (start + 0, 23)
+Highest counter ID seen: (none)

 Function name: holes::main::{closure#0} (unused)
 Raw bytes (9): 0x[01, 01, 00, 01, 00, 12, 09, 02, 0a]
@ -36,6 +39,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 18, 9) to (start + 2, 10)
+Highest counter ID seen: (none)

 Function name: holes::main::{closure#1} (unused)
 Raw bytes (9): 0x[01, 01, 00, 01, 00, 3d, 09, 02, 0a]
@ -44,4 +48,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 61, 9) to (start + 2, 10)
+Highest counter ID seen: (none)

--- a/tests/coverage/if.cov-map
+++ b/tests/coverage/if.cov-map
@ -10,4 +10,5 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 5, 6) to (start + 0, 7)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: c1

--- a/tests/coverage/if_else.cov-map
+++ b/tests/coverage/if_else.cov-map
@ -15,4 +15,5 @@ Number of file 0 mappings: 7
 - Code(Expression(1, Sub)) at (prev + 7, 5) to (start + 5, 6)
    = (c0 - c2)
 - Code(Counter(0)) at (prev + 6, 1) to (start + 0, 2)
+Highest counter ID seen: c2

--- a/tests/coverage/if_not.cov-map
+++ b/tests/coverage/if_not.cov-map
@ -20,4 +20,5 @@ Number of file 0 mappings: 10
    = (c0 - c3)
 - Code(Counter(3)) at (prev + 2, 12) to (start + 2, 6)
 - Code(Counter(0)) at (prev + 3, 1) to (start + 0, 2)
+Highest counter ID seen: c3

--- a/tests/coverage/ignore_run.cov-map
+++ b/tests/coverage/ignore_run.cov-map
@ -5,4 +5,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 3, 1) to (start + 0, 13)
+Highest counter ID seen: c0

--- a/tests/coverage/inline-dead.cov-map
+++ b/tests/coverage/inline-dead.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 23, 1) to (start + 2, 2)
+Highest counter ID seen: (none)

 Function name: inline_dead::live::<false>
 Raw bytes (26): 0x[01, 01, 01, 01, 00, 04, 01, 0e, 01, 01, 09, 00, 02, 09, 00, 0f, 02, 02, 09, 00, 0a, 01, 02, 01, 00, 02]
@ -18,6 +19,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 2, 9) to (start + 0, 10)
    = (c0 - Zero)
 - Code(Counter(0)) at (prev + 2, 1) to (start + 0, 2)
+Highest counter ID seen: c0

 Function name: inline_dead::main
 Raw bytes (14): 0x[01, 01, 00, 02, 01, 04, 01, 03, 0a, 01, 06, 05, 01, 02]
@ -27,6 +29,7 @@ Number of expressions: 0
 Number of file 0 mappings: 2
 - Code(Counter(0)) at (prev + 4, 1) to (start + 3, 10)
 - Code(Counter(0)) at (prev + 6, 5) to (start + 1, 2)
+Highest counter ID seen: c0

 Function name: inline_dead::main::{closure#0}
 Raw bytes (23): 0x[01, 01, 02, 00, 06, 01, 00, 03, 01, 07, 17, 01, 16, 00, 01, 17, 00, 18, 03, 01, 05, 00, 06]
@ -40,4 +43,5 @@ Number of file 0 mappings: 3
 - Code(Zero) at (prev + 1, 23) to (start + 0, 24)
 - Code(Expression(0, Add)) at (prev + 1, 5) to (start + 0, 6)
    = (Zero + (c0 - Zero))
+Highest counter ID seen: c0

--- a/tests/coverage/inline.cov-map
+++ b/tests/coverage/inline.cov-map
@ -11,6 +11,7 @@ Number of file 0 mappings: 5
    = (c0 + c1)
 - Code(Counter(1)) at (prev + 0, 17) to (start + 2, 6)
 - Code(Counter(0)) at (prev + 3, 5) to (start + 1, 2)
+Highest counter ID seen: c1

 Function name: inline::error
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 31, 01, 01, 14]
@ -19,6 +20,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 49, 1) to (start + 1, 20)
+Highest counter ID seen: c0

 Function name: inline::length::<char>
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 1e, 01, 02, 02]
@ -27,6 +29,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 30, 1) to (start + 2, 2)
+Highest counter ID seen: c0

 Function name: inline::main
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 05, 01, 02, 02]
@ -35,6 +38,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 5, 1) to (start + 2, 2)
+Highest counter ID seen: c0

 Function name: inline::permutate::<char>
 Raw bytes (52): 0x[01, 01, 04, 01, 05, 02, 0d, 05, 0f, 09, 0d, 08, 01, 0f, 01, 02, 0e, 05, 02, 0f, 02, 06, 02, 02, 0f, 00, 14, 11, 01, 0d, 00, 0e, 06, 00, 12, 00, 16, 11, 00, 17, 04, 0a, 0d, 05, 0c, 02, 06, 0b, 03, 01, 00, 02]
@ -57,6 +61,7 @@ Number of file 0 mappings: 8
 - Code(Counter(3)) at (prev + 5, 12) to (start + 2, 6)
 - Code(Expression(2, Add)) at (prev + 3, 1) to (start + 0, 2)
    = (c1 + (c2 + c3))
+Highest counter ID seen: c4

 Function name: inline::permutations::<char>
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 0a, 01, 03, 02]
@ -65,6 +70,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 10, 1) to (start + 3, 2)
+Highest counter ID seen: c0

 Function name: inline::swap::<char>
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 23, 01, 04, 02]
@ -73,4 +79,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 35, 1) to (start + 4, 2)
+Highest counter ID seen: c0

--- a/tests/coverage/inner_items.cov-map
+++ b/tests/coverage/inner_items.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 33, 9) to (start + 3, 10)
+Highest counter ID seen: c0

 Function name: <inner_items::main::InStruct as inner_items::main::InTrait>::trait_func
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 28, 09, 03, 0a]
@ -13,6 +14,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 40, 9) to (start + 3, 10)
+Highest counter ID seen: c0

 Function name: inner_items::main
 Raw bytes (43): 0x[01, 01, 02, 01, 05, 01, 09, 07, 01, 03, 01, 07, 0f, 05, 07, 10, 02, 06, 02, 02, 06, 00, 07, 01, 24, 08, 00, 0f, 09, 00, 10, 02, 06, 06, 02, 06, 00, 07, 01, 02, 09, 05, 02]
@ -31,6 +33,7 @@ Number of file 0 mappings: 7
 - Code(Expression(1, Sub)) at (prev + 2, 6) to (start + 0, 7)
    = (c0 - c2)
 - Code(Counter(0)) at (prev + 2, 9) to (start + 5, 2)
+Highest counter ID seen: c2

 Function name: inner_items::main::in_func
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 12, 05, 04, 06]
@ -39,4 +42,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 18, 5) to (start + 4, 6)
+Highest counter ID seen: c0

--- a/tests/coverage/issue-83601.cov-map
+++ b/tests/coverage/issue-83601.cov-map
@ -9,4 +9,5 @@ Number of file 0 mappings: 3
 - Code(Counter(1)) at (prev + 3, 9) to (start + 1, 28)
 - Code(Expression(0, Sub)) at (prev + 2, 5) to (start + 3, 2)
    = (c1 - c2)
+Highest counter ID seen: c1

--- a/tests/coverage/issue-84561.cov-map
+++ b/tests/coverage/issue-84561.cov-map
@ -10,6 +10,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 1, 9) to (start + 0, 15)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 1, 5) to (start + 0, 6)
+Highest counter ID seen: c1

 Function name: issue_84561::main
 Raw bytes (10): 0x[01, 01, 00, 01, 01, b4, 01, 01, 04, 02]
@ -18,6 +19,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 180, 1) to (start + 4, 2)
+Highest counter ID seen: c0

 Function name: issue_84561::test1
 Raw bytes (50): 0x[01, 01, 00, 09, 01, 9a, 01, 01, 01, 0b, 05, 01, 0c, 00, 1e, 01, 01, 05, 00, 0b, 09, 00, 0c, 00, 1e, 01, 01, 0d, 01, 0b, 0d, 01, 0c, 00, 1e, 01, 01, 05, 03, 0b, 11, 03, 0c, 00, 1e, 01, 01, 01, 00, 02]
@ -34,6 +36,7 @@ Number of file 0 mappings: 9
 - Code(Counter(0)) at (prev + 1, 5) to (start + 3, 11)
 - Code(Counter(4)) at (prev + 3, 12) to (start + 0, 30)
 - Code(Counter(0)) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: c4

 Function name: issue_84561::test2
 Raw bytes (20): 0x[01, 01, 00, 03, 01, b0, 01, 01, 01, 10, 05, 01, 11, 00, 23, 01, 01, 01, 00, 02]
@ -44,6 +47,7 @@ Number of file 0 mappings: 3
 - Code(Counter(0)) at (prev + 176, 1) to (start + 1, 16)
 - Code(Counter(1)) at (prev + 1, 17) to (start + 0, 35)
 - Code(Counter(0)) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: c1

 Function name: issue_84561::test2::call_print
 Raw bytes (10): 0x[01, 01, 00, 01, 01, a7, 01, 09, 02, 0a]
@ -52,6 +56,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 167, 9) to (start + 2, 10)
+Highest counter ID seen: c0

 Function name: issue_84561::test3
 Raw bytes (375): 0x[01, 01, 31, 05, 09, 0d, 00, 15, 19, 12, 00, 15, 19, 21, 00, 1e, 00, 21, 00, 31, 00, 3d, 00, 2e, 45, 3d, 00, 42, 49, 45, 00, 3f, 51, 42, 49, 45, 00, 7a, 55, 51, 00, 7a, 55, 51, 00, 77, 5d, 7a, 55, 51, 00, 77, 61, 7a, 55, 51, 00, 72, 65, 77, 61, 7a, 55, 51, 00, 75, be, 01, c2, 01, 79, 69, 6d, 69, 6d, 69, 6d, c2, 01, 00, 69, 6d, c2, 01, 79, 69, 6d, bb, 01, 7d, 75, be, 01, c2, 01, 79, 69, 6d, b6, 01, 00, bb, 01, 7d, 75, be, 01, c2, 01, 79, 69, 6d, 33, 01, 08, 01, 03, 1c, 05, 04, 09, 01, 1c, 02, 02, 05, 04, 1f, 0d, 05, 05, 00, 1f, 06, 01, 05, 00, 1f, 15, 01, 09, 01, 1c, 12, 02, 05, 00, 1f, 0e, 01, 05, 00, 0f, 00, 00, 20, 00, 30, 21, 01, 05, 03, 0f, 00, 03, 20, 00, 30, 00, 00, 33, 00, 41, 00, 00, 4b, 00, 5a, 1e, 01, 05, 00, 0f, 00, 05, 09, 03, 10, 00, 05, 0d, 00, 1b, 00, 02, 0d, 00, 1c, 1a, 04, 09, 05, 06, 31, 06, 05, 03, 06, 22, 04, 05, 03, 06, 3d, 04, 09, 04, 06, 2e, 05, 08, 00, 0f, 45, 01, 09, 03, 0a, 2a, 05, 09, 03, 0a, 3f, 05, 08, 00, 0f, 51, 01, 09, 00, 13, 00, 03, 0d, 00, 1d, 3a, 03, 09, 00, 13, 00, 03, 0d, 00, 1d, 77, 03, 05, 00, 0f, 77, 01, 0c, 00, 13, 5d, 01, 0d, 00, 13, 56, 02, 0d, 00, 13, 72, 04, 05, 02, 13, 65, 03, 0d, 00, 13, 6e, 02, 0d, 00, 13, bb, 01, 03, 05, 00, 0f, 69, 01, 0c, 00, 13, 6d, 01, 0d, 03, 0e, 75, 04, 0d, 00, 13, c2, 01, 02, 0d, 00, 17, c2, 01, 01, 14, 00, 1b, 00, 01, 15, 00, 1b, 92, 01, 02, 15, 00, 1b, be, 01, 04, 0d, 00, 13, 7d, 03, 09, 00, 19, b6, 01, 02, 05, 00, 0f, b2, 01, 03, 09, 00, 22, 00, 02, 05, 00, 0f, 00, 03, 09, 00, 2c, 00, 02, 01, 00, 02]
@ -182,4 +187,5 @@ Number of file 0 mappings: 51
 - Code(Zero) at (prev + 2, 5) to (start + 0, 15)
 - Code(Zero) at (prev + 3, 9) to (start + 0, 44)
 - Code(Zero) at (prev + 2, 1) to (start + 0, 2)
+Highest counter ID seen: c31

--- a/tests/coverage/issue-85461.cov-map
+++ b/tests/coverage/issue-85461.cov-map
@ -5,4 +5,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 8, 1) to (start + 3, 2)
+Highest counter ID seen: c0

--- a/tests/coverage/issue-93054.cov-map
+++ b/tests/coverage/issue-93054.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 21, 1) to (start + 0, 29)
+Highest counter ID seen: (none)

 Function name: issue_93054::main
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 1d, 01, 00, 0d]
@ -13,6 +14,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 29, 1) to (start + 0, 13)
+Highest counter ID seen: c0

 Function name: issue_93054::make (unused)
 Raw bytes (9): 0x[01, 01, 00, 01, 00, 19, 01, 02, 02]
@ -21,4 +23,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 25, 1) to (start + 2, 2)
+Highest counter ID seen: (none)

--- a/tests/coverage/lazy_boolean.cov-map
+++ b/tests/coverage/lazy_boolean.cov-map
@ -46,4 +46,5 @@ Number of file 0 mappings: 28
 - Code(Expression(6, Sub)) at (prev + 2, 12) to (start + 2, 6)
    = (c0 - c9)
 - Code(Counter(0)) at (prev + 3, 1) to (start + 0, 2)
+Highest counter ID seen: c9

--- a/tests/coverage/let_else_loop.cov-map
+++ b/tests/coverage/let_else_loop.cov-map
@ -7,6 +7,7 @@ Number of file 0 mappings: 3
 - Code(Zero) at (prev + 22, 1) to (start + 1, 12)
 - Code(Zero) at (prev + 1, 15) to (start + 0, 22)
 - Code(Zero) at (prev + 0, 32) to (start + 0, 39)
+Highest counter ID seen: (none)

 Function name: let_else_loop::_loop_either_way (unused)
 Raw bytes (19): 0x[01, 01, 00, 03, 00, 0f, 01, 01, 14, 00, 01, 1c, 00, 23, 00, 01, 05, 00, 0c]
@ -17,6 +18,7 @@ Number of file 0 mappings: 3
 - Code(Zero) at (prev + 15, 1) to (start + 1, 20)
 - Code(Zero) at (prev + 1, 28) to (start + 0, 35)
 - Code(Zero) at (prev + 1, 5) to (start + 0, 12)
+Highest counter ID seen: (none)

 Function name: let_else_loop::loopy
 Raw bytes (19): 0x[01, 01, 00, 03, 01, 09, 01, 01, 14, 00, 01, 1c, 00, 23, 05, 01, 01, 00, 02]
@ -27,4 +29,5 @@ Number of file 0 mappings: 3
 - Code(Counter(0)) at (prev + 9, 1) to (start + 1, 20)
 - Code(Zero) at (prev + 1, 28) to (start + 0, 35)
 - Code(Counter(1)) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: c1

--- a/tests/coverage/long_and_wide.cov-map
+++ b/tests/coverage/long_and_wide.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 150, 1) to (start + 0, 21)
+Highest counter ID seen: c0

 Function name: long_and_wide::long_function
 Raw bytes (10): 0x[01, 01, 00, 01, 01, 10, 01, 84, 01, 02]
@ -13,6 +14,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 16, 1) to (start + 132, 2)
+Highest counter ID seen: c0

 Function name: long_and_wide::main
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 07, 01, 04, 02]
@ -21,6 +23,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 7, 1) to (start + 4, 2)
+Highest counter ID seen: c0

 Function name: long_and_wide::wide_function
 Raw bytes (10): 0x[01, 01, 00, 01, 01, 0e, 01, 00, 8b, 01]
@ -29,4 +32,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 14, 1) to (start + 0, 139)
+Highest counter ID seen: c0

--- a/tests/coverage/loop-break.cov-map
+++ b/tests/coverage/loop-break.cov-map
@ -11,4 +11,5 @@ Number of file 0 mappings: 5
 - Code(Counter(0)) at (prev + 1, 13) to (start + 0, 18)
 - Code(Counter(1)) at (prev + 1, 10) to (start + 0, 11)
 - Code(Counter(0)) at (prev + 2, 1) to (start + 0, 2)
+Highest counter ID seen: c1

--- a/tests/coverage/loop_break_value.cov-map
+++ b/tests/coverage/loop_break_value.cov-map
@ -5,4 +5,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 4, 1) to (start + 10, 2)
+Highest counter ID seen: c0

--- a/tests/coverage/loops_branches.cov-map
+++ b/tests/coverage/loops_branches.cov-map
@ -75,6 +75,7 @@ Number of file 0 mappings: 20
 - Code(Counter(6)) at (prev + 3, 9) to (start + 0, 15)
 - Code(Expression(34, Add)) at (prev + 1, 5) to (start + 0, 6)
    = ((c9 + (((((c3 + Zero) + (c4 + Zero)) - c6) - Zero) - c4)) + c6)
+Highest counter ID seen: c9

 Function name: <loops_branches::DisplayTest as core::fmt::Display>::fmt
 Raw bytes (230): 0x[01, 01, 2b, 01, 00, 02, 00, a3, 01, 19, a7, 01, ab, 01, 00, 0d, 00, 15, a7, 01, ab, 01, 00, 0d, 00, 15, a3, 01, 19, a7, 01, ab, 01, 00, 0d, 00, 15, 9e, 01, 00, a3, 01, 19, a7, 01, ab, 01, 00, 0d, 00, 15, 9a, 01, 00, 9e, 01, 00, a3, 01, 19, a7, 01, ab, 01, 00, 0d, 00, 15, 9e, 01, 00, a3, 01, 19, a7, 01, ab, 01, 00, 0d, 00, 15, 9a, 01, 15, 9e, 01, 00, a3, 01, 19, a7, 01, ab, 01, 00, 0d, 00, 15, 93, 01, 25, 96, 01, 19, 9a, 01, 15, 9e, 01, 00, a3, 01, 19, a7, 01, ab, 01, 00, 0d, 00, 15, 14, 01, 22, 05, 01, 11, 00, 01, 12, 01, 0a, 02, 02, 10, 00, 15, 00, 01, 17, 00, 1b, 00, 00, 1c, 00, 1e, 06, 01, 0e, 00, 0f, 02, 01, 0d, 00, 1e, 25, 00, 1e, 00, 1f, 9e, 01, 02, 0d, 00, 0e, a3, 01, 00, 12, 00, 17, 9e, 01, 01, 10, 00, 15, 00, 00, 16, 01, 0e, 9a, 01, 02, 14, 00, 19, 00, 01, 1b, 00, 1f, 00, 00, 20, 00, 22, 4a, 01, 12, 00, 13, 9a, 01, 01, 11, 00, 22, 96, 01, 00, 22, 00, 23, 19, 03, 09, 00, 0f, 8f, 01, 01, 05, 00, 06]
@ -156,6 +157,7 @@ Number of file 0 mappings: 20
 - Code(Counter(6)) at (prev + 3, 9) to (start + 0, 15)
 - Code(Expression(35, Add)) at (prev + 1, 5) to (start + 0, 6)
    = (((((((Zero + c3) + (Zero + c5)) - c6) - Zero) - c5) + c6) + c9)
+Highest counter ID seen: c9

 Function name: loops_branches::main
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 37, 01, 05, 02]
@ -164,4 +166,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 55, 1) to (start + 5, 2)
+Highest counter ID seen: c0

--- a/tests/coverage/macro_in_closure.cov-map
+++ b/tests/coverage/macro_in_closure.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 7, 28) to (start + 0, 45)
+Highest counter ID seen: c0

 Function name: macro_in_closure::WITH_BLOCK::{closure#0}
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 09, 1e, 02, 02]
@ -13,4 +14,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 9, 30) to (start + 2, 2)
+Highest counter ID seen: c0

--- a/tests/coverage/macro_name_span.cov-map
+++ b/tests/coverage/macro_name_span.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 22, 28) to (start + 1, 64)
+Highest counter ID seen: c0

 Function name: macro_name_span::main
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 0b, 01, 02, 02]
@ -13,4 +14,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 11, 1) to (start + 2, 2)
+Highest counter ID seen: c0

--- a/tests/coverage/match_or_pattern.cov-map
+++ b/tests/coverage/match_or_pattern.cov-map
@ -72,4 +72,5 @@ Number of file 0 mappings: 25
    = (c14 + c15)
 - Code(Expression(26, Add)) at (prev + 2, 1) to (start + 0, 2)
    = ((c14 + c15) + c16)
+Highest counter ID seen: c16

--- a/tests/coverage/mcdc/condition-limit.cov-map
+++ b/tests/coverage/mcdc/condition-limit.cov-map
@ -87,4 +87,5 @@ Number of file 0 mappings: 18
    = ((((((c2 + c3) + c4) + c5) + c6) + c7) + (c0 - c1))
 - Code(Expression(37, Add)) at (prev + 1, 1) to (start + 0, 2)
    = (c8 + ((((((c2 + c3) + c4) + c5) + c6) + c7) + (c0 - c1)))
+Highest counter ID seen: c8

--- a/tests/coverage/mcdc/if.cov-map
+++ b/tests/coverage/mcdc/if.cov-map
@ -22,6 +22,7 @@ Number of file 0 mappings: 8
    = (c2 + (c0 - c1))
 - Code(Expression(2, Add)) at (prev + 3, 1) to (start + 0, 2)
    = (c3 + (c2 + (c0 - c1)))
+Highest counter ID seen: c3

 Function name: if::mcdc_check_b
 Raw bytes (64): 0x[01, 01, 04, 01, 05, 09, 02, 0d, 0f, 09, 02, 08, 01, 17, 01, 01, 09, 28, 03, 02, 01, 08, 00, 0e, 30, 05, 02, 01, 02, 00, 00, 08, 00, 09, 05, 00, 0d, 00, 0e, 30, 0d, 09, 02, 00, 00, 00, 0d, 00, 0e, 0d, 00, 0f, 02, 06, 0f, 02, 0c, 02, 06, 0b, 03, 01, 00, 02]
@ -47,6 +48,7 @@ Number of file 0 mappings: 8
    = (c2 + (c0 - c1))
 - Code(Expression(2, Add)) at (prev + 3, 1) to (start + 0, 2)
    = (c3 + (c2 + (c0 - c1)))
+Highest counter ID seen: c3

 Function name: if::mcdc_check_both
 Raw bytes (64): 0x[01, 01, 04, 01, 05, 09, 02, 0d, 0f, 09, 02, 08, 01, 1f, 01, 01, 09, 28, 03, 02, 01, 08, 00, 0e, 30, 05, 02, 01, 02, 00, 00, 08, 00, 09, 05, 00, 0d, 00, 0e, 30, 0d, 09, 02, 00, 00, 00, 0d, 00, 0e, 0d, 00, 0f, 02, 06, 0f, 02, 0c, 02, 06, 0b, 03, 01, 00, 02]
@ -72,6 +74,7 @@ Number of file 0 mappings: 8
    = (c2 + (c0 - c1))
 - Code(Expression(2, Add)) at (prev + 3, 1) to (start + 0, 2)
    = (c3 + (c2 + (c0 - c1)))
+Highest counter ID seen: c3

 Function name: if::mcdc_check_neither
 Raw bytes (64): 0x[01, 01, 04, 01, 05, 09, 02, 0d, 0f, 09, 02, 08, 01, 07, 01, 01, 09, 28, 03, 02, 01, 08, 00, 0e, 30, 05, 02, 01, 02, 00, 00, 08, 00, 09, 05, 00, 0d, 00, 0e, 30, 0d, 09, 02, 00, 00, 00, 0d, 00, 0e, 0d, 00, 0f, 02, 06, 0f, 02, 0c, 02, 06, 0b, 03, 01, 00, 02]
@ -97,6 +100,7 @@ Number of file 0 mappings: 8
    = (c2 + (c0 - c1))
 - Code(Expression(2, Add)) at (prev + 3, 1) to (start + 0, 2)
    = (c3 + (c2 + (c0 - c1)))
+Highest counter ID seen: c3

 Function name: if::mcdc_check_not_tree_decision
 Raw bytes (87): 0x[01, 01, 08, 01, 05, 02, 09, 05, 09, 0d, 1e, 02, 09, 11, 1b, 0d, 1e, 02, 09, 0a, 01, 31, 01, 03, 0a, 28, 05, 03, 03, 08, 00, 15, 30, 05, 02, 01, 02, 03, 00, 09, 00, 0a, 02, 00, 0e, 00, 0f, 30, 09, 1e, 03, 02, 00, 00, 0e, 00, 0f, 0b, 00, 14, 00, 15, 30, 11, 0d, 02, 00, 00, 00, 14, 00, 15, 11, 00, 16, 02, 06, 1b, 02, 0c, 02, 06, 17, 03, 01, 00, 02]
@ -132,6 +136,7 @@ Number of file 0 mappings: 10
    = (c3 + ((c0 - c1) - c2))
 - Code(Expression(5, Add)) at (prev + 3, 1) to (start + 0, 2)
    = (c4 + (c3 + ((c0 - c1) - c2)))
+Highest counter ID seen: c4

 Function name: if::mcdc_check_tree_decision
 Raw bytes (87): 0x[01, 01, 08, 01, 05, 05, 0d, 05, 0d, 0d, 11, 09, 02, 1b, 1f, 0d, 11, 09, 02, 0a, 01, 27, 01, 03, 09, 28, 04, 03, 03, 08, 00, 15, 30, 05, 02, 01, 02, 00, 00, 08, 00, 09, 05, 00, 0e, 00, 0f, 30, 0d, 0a, 02, 00, 03, 00, 0e, 00, 0f, 0a, 00, 13, 00, 14, 30, 11, 09, 03, 00, 00, 00, 13, 00, 14, 1b, 00, 16, 02, 06, 1f, 02, 0c, 02, 06, 17, 03, 01, 00, 02]
@ -167,6 +172,7 @@ Number of file 0 mappings: 10
    = (c2 + (c0 - c1))
 - Code(Expression(5, Add)) at (prev + 3, 1) to (start + 0, 2)
    = ((c3 + c4) + (c2 + (c0 - c1)))
+Highest counter ID seen: c4

 Function name: if::mcdc_nested_if
 Raw bytes (124): 0x[01, 01, 0d, 01, 05, 02, 09, 05, 09, 1b, 15, 05, 09, 1b, 15, 05, 09, 11, 15, 02, 09, 2b, 32, 0d, 2f, 11, 15, 02, 09, 0e, 01, 3b, 01, 01, 09, 28, 03, 02, 01, 08, 00, 0e, 30, 05, 02, 01, 00, 02, 00, 08, 00, 09, 02, 00, 0d, 00, 0e, 30, 09, 32, 02, 00, 00, 00, 0d, 00, 0e, 1b, 01, 09, 01, 0d, 28, 06, 02, 01, 0c, 00, 12, 30, 16, 15, 01, 02, 00, 00, 0c, 00, 0d, 16, 00, 11, 00, 12, 30, 0d, 11, 02, 00, 00, 00, 11, 00, 12, 0d, 00, 13, 02, 0a, 2f, 02, 0a, 00, 0b, 32, 01, 0c, 02, 06, 27, 03, 01, 00, 02]
@ -215,4 +221,5 @@ Number of file 0 mappings: 14
    = ((c0 - c1) - c2)
 - Code(Expression(9, Add)) at (prev + 3, 1) to (start + 0, 2)
    = ((c3 + (c4 + c5)) + ((c0 - c1) - c2))
+Highest counter ID seen: c5

--- a/tests/coverage/mcdc/inlined_expressions.cov-map
+++ b/tests/coverage/mcdc/inlined_expressions.cov-map
@ -18,4 +18,5 @@ Number of file 0 mappings: 6
    false = c3
 - Code(Expression(1, Add)) at (prev + 1, 1) to (start + 0, 2)
    = ((c2 + c3) + (c0 - c1))
+Highest counter ID seen: c3

--- a/tests/coverage/mcdc/nested_if.cov-map
+++ b/tests/coverage/mcdc/nested_if.cov-map
@ -56,6 +56,7 @@ Number of file 0 mappings: 20
    = (c2 + (c0 - c1))
 - Code(Expression(12, Add)) at (prev + 3, 1) to (start + 0, 2)
    = (c3 + (c2 + (c0 - c1)))
+Highest counter ID seen: c8

 Function name: nested_if::nested_if_in_condition
 Raw bytes (120): 0x[01, 01, 0b, 01, 05, 05, 11, 05, 11, 1e, 15, 05, 11, 11, 15, 1e, 15, 05, 11, 09, 02, 0d, 2b, 09, 02, 0e, 01, 07, 01, 01, 09, 28, 06, 02, 01, 08, 00, 2e, 30, 05, 02, 01, 02, 00, 00, 08, 00, 09, 30, 0d, 09, 02, 00, 00, 00, 0d, 00, 2e, 05, 00, 10, 00, 11, 28, 03, 02, 00, 10, 00, 16, 30, 11, 1e, 01, 00, 02, 00, 10, 00, 11, 1e, 00, 15, 00, 16, 30, 15, 1a, 02, 00, 00, 00, 15, 00, 16, 17, 00, 19, 00, 1d, 1a, 00, 27, 00, 2c, 0d, 00, 2f, 02, 06, 2b, 02, 0c, 02, 06, 27, 03, 01, 00, 02]
@ -101,6 +102,7 @@ Number of file 0 mappings: 14
    = (c2 + (c0 - c1))
 - Code(Expression(9, Add)) at (prev + 3, 1) to (start + 0, 2)
    = (c3 + (c2 + (c0 - c1)))
+Highest counter ID seen: c5

 Function name: nested_if::nested_in_then_block_in_condition
 Raw bytes (176): 0x[01, 01, 12, 01, 05, 05, 11, 05, 11, 3a, 15, 05, 11, 11, 15, 33, 19, 11, 15, 19, 1d, 19, 1d, 1d, 2e, 33, 19, 11, 15, 3a, 15, 05, 11, 09, 02, 0d, 47, 09, 02, 14, 01, 22, 01, 01, 09, 28, 09, 02, 01, 08, 00, 4b, 30, 05, 02, 01, 02, 00, 00, 08, 00, 09, 30, 0d, 09, 02, 00, 00, 00, 0d, 00, 4b, 05, 00, 10, 00, 11, 28, 03, 02, 00, 10, 00, 16, 30, 11, 3a, 01, 00, 02, 00, 10, 00, 11, 3a, 00, 15, 00, 16, 30, 15, 36, 02, 00, 00, 00, 15, 00, 16, 33, 00, 1c, 00, 1d, 28, 06, 02, 00, 1c, 00, 22, 30, 19, 2e, 01, 02, 00, 00, 1c, 00, 1d, 19, 00, 21, 00, 22, 30, 26, 1d, 02, 00, 00, 00, 21, 00, 22, 26, 00, 25, 00, 29, 2b, 00, 33, 00, 38, 36, 00, 44, 00, 49, 0d, 00, 4c, 02, 06, 47, 02, 0c, 02, 06, 43, 03, 01, 00, 02]
@ -165,6 +167,7 @@ Number of file 0 mappings: 20
    = (c2 + (c0 - c1))
 - Code(Expression(16, Add)) at (prev + 3, 1) to (start + 0, 2)
    = (c3 + (c2 + (c0 - c1)))
+Highest counter ID seen: c7

 Function name: nested_if::nested_single_condition_decision
 Raw bytes (85): 0x[01, 01, 06, 01, 05, 05, 11, 05, 11, 09, 02, 0d, 17, 09, 02, 0b, 01, 17, 01, 04, 09, 28, 03, 02, 04, 08, 00, 29, 30, 05, 02, 01, 02, 00, 00, 08, 00, 09, 30, 0d, 09, 02, 00, 00, 00, 0d, 00, 29, 05, 00, 10, 00, 11, 20, 11, 0a, 00, 10, 00, 11, 11, 00, 14, 00, 19, 0a, 00, 23, 00, 27, 0d, 00, 2a, 02, 06, 17, 02, 0c, 02, 06, 13, 03, 01, 00, 02]
@ -198,4 +201,5 @@ Number of file 0 mappings: 11
    = (c2 + (c0 - c1))
 - Code(Expression(4, Add)) at (prev + 3, 1) to (start + 0, 2)
    = (c3 + (c2 + (c0 - c1)))
+Highest counter ID seen: c4

--- a/tests/coverage/mcdc/non_control_flow.cov-map
+++ b/tests/coverage/mcdc/non_control_flow.cov-map
@ -33,6 +33,7 @@ Number of file 0 mappings: 10
    false = c3
 - Code(Expression(0, Add)) at (prev + 1, 5) to (start + 1, 2)
    = (c1 + ((c2 + c3) + c4))
+Highest counter ID seen: c4

 Function name: non_control_flow::assign_3_bis
 Raw bytes (85): 0x[01, 01, 07, 07, 11, 09, 0d, 01, 05, 05, 09, 16, 1a, 05, 09, 01, 05, 0a, 01, 1b, 01, 00, 2c, 03, 01, 09, 00, 0a, 01, 00, 0d, 00, 0e, 28, 05, 03, 00, 0d, 00, 18, 30, 05, 1a, 01, 03, 02, 00, 0d, 00, 0e, 05, 00, 12, 00, 13, 30, 09, 16, 03, 00, 02, 00, 12, 00, 13, 13, 00, 17, 00, 18, 30, 0d, 11, 02, 00, 00, 00, 17, 00, 18, 03, 01, 05, 01, 02]
@ -66,6 +67,7 @@ Number of file 0 mappings: 10
    false = c4
 - Code(Expression(0, Add)) at (prev + 1, 5) to (start + 1, 2)
    = ((c2 + c3) + c4)
+Highest counter ID seen: c4

 Function name: non_control_flow::assign_and
 Raw bytes (64): 0x[01, 01, 04, 07, 0e, 09, 0d, 01, 05, 01, 05, 08, 01, 0c, 01, 00, 21, 03, 01, 09, 00, 0a, 01, 00, 0d, 00, 0e, 28, 03, 02, 00, 0d, 00, 13, 30, 05, 0e, 01, 02, 00, 00, 0d, 00, 0e, 05, 00, 12, 00, 13, 30, 09, 0d, 02, 00, 00, 00, 12, 00, 13, 03, 01, 05, 01, 02]
@ -91,6 +93,7 @@ Number of file 0 mappings: 8
    false = c3
 - Code(Expression(0, Add)) at (prev + 1, 5) to (start + 1, 2)
    = ((c2 + c3) + (c0 - c1))
+Highest counter ID seen: c3

 Function name: non_control_flow::assign_or
 Raw bytes (64): 0x[01, 01, 04, 07, 0d, 05, 09, 01, 05, 01, 05, 08, 01, 11, 01, 00, 20, 03, 01, 09, 00, 0a, 01, 00, 0d, 00, 0e, 28, 03, 02, 00, 0d, 00, 13, 30, 05, 0e, 01, 00, 02, 00, 0d, 00, 0e, 0e, 00, 12, 00, 13, 30, 09, 0d, 02, 00, 00, 00, 12, 00, 13, 03, 01, 05, 01, 02]
@ -117,6 +120,7 @@ Number of file 0 mappings: 8
    false = c3
 - Code(Expression(0, Add)) at (prev + 1, 5) to (start + 1, 2)
    = ((c1 + c2) + c3)
+Highest counter ID seen: c3

 Function name: non_control_flow::foo
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 25, 01, 02, 02]
@ -125,6 +129,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 37, 1) to (start + 2, 2)
+Highest counter ID seen: c0

 Function name: non_control_flow::func_call
 Raw bytes (52): 0x[01, 01, 03, 01, 05, 0b, 02, 09, 0d, 06, 01, 29, 01, 01, 0a, 28, 03, 02, 01, 09, 00, 0f, 30, 05, 02, 01, 02, 00, 00, 09, 00, 0a, 05, 00, 0e, 00, 0f, 30, 09, 0d, 02, 00, 00, 00, 0e, 00, 0f, 07, 01, 01, 00, 02]
@ -146,6 +151,7 @@ Number of file 0 mappings: 6
    false = c3
 - Code(Expression(1, Add)) at (prev + 1, 1) to (start + 0, 2)
    = ((c2 + c3) + (c0 - c1))
+Highest counter ID seen: c3

 Function name: non_control_flow::right_comb_tree
 Raw bytes (139): 0x[01, 01, 13, 07, 1a, 0b, 19, 0f, 15, 13, 11, 09, 0d, 01, 05, 01, 05, 05, 19, 05, 19, 4a, 15, 05, 19, 4a, 15, 05, 19, 46, 11, 4a, 15, 05, 19, 46, 11, 4a, 15, 05, 19, 0e, 01, 20, 01, 00, 41, 03, 01, 09, 00, 0a, 01, 00, 0d, 00, 0e, 28, 06, 05, 00, 0d, 00, 2a, 30, 05, 1a, 01, 02, 00, 00, 0d, 00, 0e, 05, 00, 13, 00, 14, 30, 4a, 19, 02, 03, 00, 00, 13, 00, 14, 4a, 00, 19, 00, 1a, 30, 46, 15, 03, 04, 00, 00, 19, 00, 1a, 46, 00, 1f, 00, 20, 30, 42, 11, 04, 05, 00, 00, 1f, 00, 20, 42, 00, 24, 00, 27, 30, 09, 0d, 05, 00, 00, 00, 24, 00, 27, 03, 01, 05, 01, 02]
@ -201,4 +207,5 @@ Number of file 0 mappings: 14
    false = c3
 - Code(Expression(0, Add)) at (prev + 1, 5) to (start + 1, 2)
    = (((((c2 + c3) + c4) + c5) + c6) + (c0 - c1))
+Highest counter ID seen: c6

--- a/tests/coverage/nested_loops.cov-map
+++ b/tests/coverage/nested_loops.cov-map
@ -48,4 +48,5 @@ Number of file 0 mappings: 13
    = (c1 + c2)
 - Code(Expression(22, Add)) at (prev + 2, 1) to (start + 0, 2)
    = (c4 + c3)
+Highest counter ID seen: c6

--- a/tests/coverage/no_cov_crate.cov-map
+++ b/tests/coverage/no_cov_crate.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 20, 1) to (start + 2, 2)
+Highest counter ID seen: c0

 Function name: no_cov_crate::add_coverage_2
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 18, 01, 02, 02]
@ -13,6 +14,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 24, 1) to (start + 2, 2)
+Highest counter ID seen: c0

 Function name: no_cov_crate::add_coverage_not_called (unused)
 Raw bytes (9): 0x[01, 01, 00, 01, 00, 1d, 01, 02, 02]
@ -21,6 +23,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 29, 1) to (start + 2, 2)
+Highest counter ID seen: (none)

 Function name: no_cov_crate::main
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 4d, 01, 0b, 02]
@ -29,6 +32,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 77, 1) to (start + 11, 2)
+Highest counter ID seen: c0

 Function name: no_cov_crate::nested_fns::outer
 Raw bytes (14): 0x[01, 01, 00, 02, 01, 31, 05, 02, 23, 01, 0c, 05, 00, 06]
@ -38,6 +42,7 @@ Number of expressions: 0
 Number of file 0 mappings: 2
 - Code(Counter(0)) at (prev + 49, 5) to (start + 2, 35)
 - Code(Counter(0)) at (prev + 12, 5) to (start + 0, 6)
+Highest counter ID seen: c0

 Function name: no_cov_crate::nested_fns::outer_both_covered
 Raw bytes (14): 0x[01, 01, 00, 02, 01, 3f, 05, 02, 17, 01, 0b, 05, 00, 06]
@ -47,6 +52,7 @@ Number of expressions: 0
 Number of file 0 mappings: 2
 - Code(Counter(0)) at (prev + 63, 5) to (start + 2, 23)
 - Code(Counter(0)) at (prev + 11, 5) to (start + 0, 6)
+Highest counter ID seen: c0

 Function name: no_cov_crate::nested_fns::outer_both_covered::inner
 Raw bytes (26): 0x[01, 01, 01, 01, 05, 04, 01, 43, 09, 01, 17, 05, 01, 18, 02, 0e, 02, 02, 14, 02, 0e, 01, 03, 09, 00, 0a]
@ -60,4 +66,5 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 2, 20) to (start + 2, 14)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 3, 9) to (start + 0, 10)
+Highest counter ID seen: c1

--- a/tests/coverage/no_spans.cov-map
+++ b/tests/coverage/no_spans.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 26, 28) to (start + 0, 29)
+Highest counter ID seen: c0

 Function name: no_spans::affected_function::{closure#0}
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 1b, 0c, 00, 0e]
@ -13,4 +14,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 27, 12) to (start + 0, 14)
+Highest counter ID seen: c0

--- a/tests/coverage/no_spans_if_not.cov-map
+++ b/tests/coverage/no_spans_if_not.cov-map
@ -9,6 +9,7 @@ Number of file 0 mappings: 3
 - Code(Expression(0, Sub)) at (prev + 2, 13) to (start + 0, 15)
    = (c0 - Zero)
 - Code(Zero) at (prev + 2, 13) to (start + 0, 15)
+Highest counter ID seen: c0

 Function name: no_spans_if_not::main
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 0b, 01, 02, 02]
@ -17,4 +18,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 11, 1) to (start + 2, 2)
+Highest counter ID seen: c0

--- a/tests/coverage/overflow.cov-map
+++ b/tests/coverage/overflow.cov-map
@ -25,6 +25,7 @@ Number of file 0 mappings: 9
 - Code(Expression(6, Add)) at (prev + 1, 9) to (start + 0, 23)
    = (c1 + (c2 + c3))
 - Code(Counter(4)) at (prev + 2, 5) to (start + 1, 2)
+Highest counter ID seen: c4

 Function name: overflow::might_overflow
 Raw bytes (26): 0x[01, 01, 01, 01, 05, 04, 01, 05, 01, 01, 12, 05, 01, 13, 02, 06, 02, 02, 06, 00, 07, 01, 01, 09, 05, 02]
@ -38,4 +39,5 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 2, 6) to (start + 0, 7)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 1, 9) to (start + 5, 2)
+Highest counter ID seen: c1

--- a/tests/coverage/panic_unwind.cov-map
+++ b/tests/coverage/panic_unwind.cov-map
@ -25,6 +25,7 @@ Number of file 0 mappings: 9
 - Code(Expression(6, Add)) at (prev + 1, 9) to (start + 0, 23)
    = (c1 + (c2 + c3))
 - Code(Counter(4)) at (prev + 2, 5) to (start + 1, 2)
+Highest counter ID seen: c4

 Function name: panic_unwind::might_panic
 Raw bytes (21): 0x[01, 01, 01, 01, 05, 03, 01, 04, 01, 01, 14, 05, 02, 09, 01, 19, 02, 02, 0c, 03, 02]
@ -37,4 +38,5 @@ Number of file 0 mappings: 3
 - Code(Counter(1)) at (prev + 2, 9) to (start + 1, 25)
 - Code(Expression(0, Sub)) at (prev + 2, 12) to (start + 3, 2)
    = (c0 - c1)
+Highest counter ID seen: c1

--- a/tests/coverage/partial_eq.cov-map
+++ b/tests/coverage/partial_eq.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 12, 5) to (start + 2, 6)
+Highest counter ID seen: c0

 Function name: partial_eq::main
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 11, 01, 0a, 02]
@ -13,4 +14,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 17, 1) to (start + 10, 2)
+Highest counter ID seen: c0

--- a/tests/coverage/simple_loop.cov-map
+++ b/tests/coverage/simple_loop.cov-map
@ -15,4 +15,5 @@ Number of file 0 mappings: 7
 - Code(Counter(0)) at (prev + 4, 13) to (start + 0, 18)
 - Code(Counter(2)) at (prev + 2, 10) to (start + 3, 10)
 - Code(Counter(0)) at (prev + 6, 1) to (start + 0, 2)
+Highest counter ID seen: c2

--- a/tests/coverage/simple_match.cov-map
+++ b/tests/coverage/simple_match.cov-map
@ -27,4 +27,5 @@ Number of file 0 mappings: 10
 - Code(Counter(2)) at (prev + 4, 13) to (start + 7, 14)
 - Code(Counter(3)) at (prev + 10, 13) to (start + 0, 15)
 - Code(Counter(4)) at (prev + 3, 1) to (start + 0, 2)
+Highest counter ID seen: c4

--- a/tests/coverage/sort_groups.cov-map
+++ b/tests/coverage/sort_groups.cov-map
@ -10,6 +10,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 2, 6) to (start + 0, 7)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: c1

 Function name: sort_groups::generic_fn::<()>
 Raw bytes (26): 0x[01, 01, 01, 01, 05, 04, 01, 11, 01, 01, 0c, 05, 01, 0d, 02, 06, 02, 02, 06, 00, 07, 01, 01, 01, 00, 02]
@ -23,6 +24,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 2, 6) to (start + 0, 7)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: c1

 Function name: sort_groups::generic_fn::<char>
 Raw bytes (26): 0x[01, 01, 01, 01, 05, 04, 01, 11, 01, 01, 0c, 05, 01, 0d, 02, 06, 02, 02, 06, 00, 07, 01, 01, 01, 00, 02]
@ -36,6 +38,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 2, 6) to (start + 0, 7)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: c1

 Function name: sort_groups::generic_fn::<i32>
 Raw bytes (26): 0x[01, 01, 01, 01, 05, 04, 01, 11, 01, 01, 0c, 05, 01, 0d, 02, 06, 02, 02, 06, 00, 07, 01, 01, 01, 00, 02]
@ -49,6 +52,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 2, 6) to (start + 0, 7)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: c1

 Function name: sort_groups::main
 Raw bytes (26): 0x[01, 01, 01, 01, 05, 04, 01, 06, 01, 04, 23, 05, 04, 24, 02, 06, 02, 02, 06, 00, 07, 01, 01, 05, 02, 02]
@ -62,6 +66,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 2, 6) to (start + 0, 7)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 1, 5) to (start + 2, 2)
+Highest counter ID seen: c1

 Function name: sort_groups::other_fn
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 17, 01, 00, 11]
@ -70,4 +75,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 23, 1) to (start + 0, 17)
+Highest counter ID seen: c0

--- a/tests/coverage/test_harness.cov-map
+++ b/tests/coverage/test_harness.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 10, 1) to (start + 0, 16)
+Highest counter ID seen: c0

 Function name: test_harness::unused (unused)
 Raw bytes (9): 0x[01, 01, 00, 01, 00, 07, 01, 00, 0f]
@ -13,4 +14,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 7, 1) to (start + 0, 15)
+Highest counter ID seen: (none)

--- a/tests/coverage/tight_inf_loop.cov-map
+++ b/tests/coverage/tight_inf_loop.cov-map
@ -9,4 +9,5 @@ Number of file 0 mappings: 3
 - Code(Zero) at (prev + 2, 9) to (start + 0, 16)
 - Code(Expression(0, Sub)) at (prev + 1, 6) to (start + 1, 2)
    = (c0 - Zero)
+Highest counter ID seen: c0

--- a/tests/coverage/trivial.cov-map
+++ b/tests/coverage/trivial.cov-map
@ -5,4 +5,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 3, 1) to (start + 0, 13)
+Highest counter ID seen: c0

--- a/tests/coverage/try_error_result.cov-map
+++ b/tests/coverage/try_error_result.cov-map
@ -10,6 +10,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 2, 13) to (start + 0, 26)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 2, 5) to (start + 0, 6)
+Highest counter ID seen: c1

 Function name: <try_error_result::Thing2>::call
 Raw bytes (26): 0x[01, 01, 01, 01, 05, 04, 01, 34, 05, 01, 18, 05, 02, 0d, 00, 14, 02, 02, 0d, 00, 13, 01, 02, 05, 00, 06]
@ -23,6 +24,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 2, 13) to (start + 0, 19)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 2, 5) to (start + 0, 6)
+Highest counter ID seen: c1

 Function name: try_error_result::call
 Raw bytes (26): 0x[01, 01, 01, 01, 05, 04, 01, 05, 01, 01, 14, 05, 02, 09, 00, 10, 02, 02, 09, 00, 0f, 01, 02, 01, 00, 02]
@ -36,6 +38,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 2, 9) to (start + 0, 15)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 2, 1) to (start + 0, 2)
+Highest counter ID seen: c1

 Function name: try_error_result::main
 Raw bytes (26): 0x[01, 01, 01, 01, 05, 04, 01, 71, 01, 02, 0c, 05, 03, 05, 00, 06, 02, 02, 05, 00, 0b, 01, 01, 01, 00, 02]
@ -49,6 +52,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 2, 5) to (start + 0, 11)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: c1

 Function name: try_error_result::test1
 Raw bytes (75): 0x[01, 01, 08, 01, 07, 00, 09, 03, 0d, 12, 1d, 03, 0d, 1b, 0d, 1f, 00, 11, 00, 0b, 01, 0d, 01, 02, 17, 03, 07, 09, 00, 0e, 12, 02, 09, 04, 1a, 1d, 06, 0d, 00, 29, 11, 00, 29, 00, 2a, 00, 01, 0d, 00, 2a, 00, 00, 2a, 00, 2b, 0e, 04, 0d, 00, 2a, 00, 00, 2a, 00, 2b, 0d, 03, 05, 00, 0b, 17, 01, 01, 00, 02]
@ -79,6 +83,7 @@ Number of file 0 mappings: 11
 - Code(Counter(3)) at (prev + 3, 5) to (start + 0, 11)
 - Code(Expression(5, Add)) at (prev + 1, 1) to (start + 0, 2)
    = (((c4 + Zero) + Zero) + c3)
+Highest counter ID seen: c7

 Function name: try_error_result::test2
 Raw bytes (358): 0x[01, 01, 3b, 01, 07, 05, 09, 03, 0d, 41, 11, 4a, 15, 41, 11, 42, 1d, 46, 19, 4a, 15, 41, 11, 4a, 15, 41, 11, 46, 19, 4a, 15, 41, 11, 42, 1d, 46, 19, 4a, 15, 41, 11, 5e, 25, 49, 21, 49, 21, 5e, 25, 49, 21, 8a, 01, 2d, 8e, 01, 29, 92, 01, 41, 03, 0d, 92, 01, 41, 03, 0d, 8e, 01, 29, 92, 01, 41, 03, 0d, 8a, 01, 2d, 8e, 01, 29, 92, 01, 41, 03, 0d, a6, 01, 35, 45, 31, 45, 31, a6, 01, 35, 45, 31, ba, 01, 3d, 4d, 39, 4d, 39, ba, 01, 3d, 4d, 39, c3, 01, 0d, c7, 01, db, 01, cb, 01, cf, 01, 11, 15, d3, 01, d7, 01, 19, 1d, 21, 25, df, 01, e3, 01, 29, 2d, e7, 01, eb, 01, 31, 35, 39, 3d, 28, 01, 3d, 01, 03, 17, 03, 08, 09, 00, 0e, 92, 01, 02, 09, 04, 1a, 41, 06, 0d, 00, 2f, 11, 00, 2f, 00, 30, 4a, 00, 31, 03, 35, 15, 04, 11, 00, 12, 46, 02, 11, 04, 12, 3e, 05, 11, 00, 14, 46, 00, 17, 00, 41, 19, 00, 41, 00, 42, 42, 00, 43, 00, 5f, 1d, 00, 5f, 00, 60, 3e, 01, 0d, 00, 20, 5a, 01, 11, 00, 14, 49, 00, 17, 00, 41, 21, 00, 41, 00, 42, 5e, 00, 43, 00, 60, 25, 00, 60, 00, 61, 5a, 01, 0d, 00, 20, 86, 01, 04, 11, 00, 14, 8e, 01, 00, 17, 00, 42, 29, 00, 42, 00, 43, 8a, 01, 00, 44, 00, 61, 2d, 00, 61, 00, 62, 86, 01, 01, 0d, 00, 20, a2, 01, 01, 11, 00, 14, 45, 00, 17, 01, 36, 31, 01, 36, 00, 37, a6, 01, 01, 12, 00, 2f, 35, 00, 2f, 00, 30, a2, 01, 01, 0d, 00, 20, b6, 01, 01, 11, 00, 14, 4d, 00, 17, 01, 36, 39, 02, 11, 00, 12, ba, 01, 01, 12, 00, 2f, 3d, 01, 11, 00, 12, b6, 01, 02, 0d, 00, 20, 0d, 03, 05, 00, 0b, bf, 01, 01, 01, 00, 02]
@ -207,4 +212,5 @@ Number of file 0 mappings: 40
 - Code(Counter(3)) at (prev + 3, 5) to (start + 0, 11)
 - Code(Expression(47, Add)) at (prev + 1, 1) to (start + 0, 2)
    = ((((c4 + c5) + ((c6 + c7) + (c8 + c9))) + ((c10 + c11) + ((c12 + c13) + (c14 + c15)))) + c3)
+Highest counter ID seen: c19

--- a/tests/coverage/unicode.cov-map
+++ b/tests/coverage/unicode.cov-map
@ -22,6 +22,7 @@ Number of file 0 mappings: 9
    = ((c0 - c2) + c3)
 - Code(Expression(3, Add)) at (prev + 2, 5) to (start + 1, 2)
    = (c4 + ((c0 - c2) + c3))
+Highest counter ID seen: c4

 Function name: unicode::他 (unused)
 Raw bytes (9): 0x[01, 01, 00, 01, 00, 1e, 19, 00, 25]
@ -30,6 +31,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 30, 25) to (start + 0, 37)
+Highest counter ID seen: (none)

 Function name: unicode::申し訳ございません
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 18, 01, 02, 02]
@ -38,4 +40,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 24, 1) to (start + 2, 2)
+Highest counter ID seen: c0

--- a/tests/coverage/unreachable.cov-map
+++ b/tests/coverage/unreachable.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 15, 39) to (start + 0, 71)
+Highest counter ID seen: (none)

 Function name: unreachable::unreachable_function (unused)
 Raw bytes (9): 0x[01, 01, 00, 01, 00, 11, 01, 01, 25]
@ -13,6 +14,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 17, 1) to (start + 1, 37)
+Highest counter ID seen: (none)

 Function name: unreachable::unreachable_intrinsic (unused)
 Raw bytes (9): 0x[01, 01, 00, 01, 00, 16, 01, 01, 2c]
@ -21,4 +23,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 22, 1) to (start + 1, 44)
+Highest counter ID seen: (none)

--- a/tests/coverage/unused.cov-map
+++ b/tests/coverage/unused.cov-map
@ -17,6 +17,7 @@ Number of file 0 mappings: 6
 - Code(Expression(3, Add)) at (prev + 1, 9) to (start + 0, 15)
    = (c1 + c2)
 - Code(Counter(3)) at (prev + 2, 1) to (start + 0, 2)
+Highest counter ID seen: c3

 Function name: unused::foo::<u32>
 Raw bytes (42): 0x[01, 01, 04, 01, 0f, 05, 09, 03, 0d, 05, 09, 06, 01, 03, 01, 01, 12, 03, 02, 0b, 00, 11, 0a, 01, 09, 00, 0f, 09, 00, 13, 00, 19, 0f, 01, 09, 00, 0f, 0d, 02, 01, 00, 02]
@ -37,6 +38,7 @@ Number of file 0 mappings: 6
 - Code(Expression(3, Add)) at (prev + 1, 9) to (start + 0, 15)
    = (c1 + c2)
 - Code(Counter(3)) at (prev + 2, 1) to (start + 0, 2)
+Highest counter ID seen: c3

 Function name: unused::main
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 25, 01, 04, 02]
@ -45,6 +47,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 37, 1) to (start + 4, 2)
+Highest counter ID seen: c0

 Function name: unused::unused_func (unused)
 Raw bytes (24): 0x[01, 01, 00, 04, 00, 13, 01, 01, 0e, 00, 01, 0f, 02, 06, 00, 02, 06, 00, 07, 00, 01, 01, 00, 02]
@ -56,6 +59,7 @@ Number of file 0 mappings: 4
 - Code(Zero) at (prev + 1, 15) to (start + 2, 6)
 - Code(Zero) at (prev + 2, 6) to (start + 0, 7)
 - Code(Zero) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: (none)

 Function name: unused::unused_func2 (unused)
 Raw bytes (24): 0x[01, 01, 00, 04, 00, 19, 01, 01, 0e, 00, 01, 0f, 02, 06, 00, 02, 06, 00, 07, 00, 01, 01, 00, 02]
@ -67,6 +71,7 @@ Number of file 0 mappings: 4
 - Code(Zero) at (prev + 1, 15) to (start + 2, 6)
 - Code(Zero) at (prev + 2, 6) to (start + 0, 7)
 - Code(Zero) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: (none)

 Function name: unused::unused_func3 (unused)
 Raw bytes (24): 0x[01, 01, 00, 04, 00, 1f, 01, 01, 0e, 00, 01, 0f, 02, 06, 00, 02, 06, 00, 07, 00, 01, 01, 00, 02]
@ -78,6 +83,7 @@ Number of file 0 mappings: 4
 - Code(Zero) at (prev + 1, 15) to (start + 2, 6)
 - Code(Zero) at (prev + 2, 6) to (start + 0, 7)
 - Code(Zero) at (prev + 1, 1) to (start + 0, 2)
+Highest counter ID seen: (none)

 Function name: unused::unused_template_func::<_> (unused)
 Raw bytes (34): 0x[01, 01, 00, 06, 00, 0b, 01, 01, 12, 00, 02, 0b, 00, 11, 00, 01, 09, 00, 0f, 00, 00, 13, 00, 19, 00, 01, 09, 00, 0f, 00, 02, 01, 00, 02]
@ -91,4 +97,5 @@ Number of file 0 mappings: 6
 - Code(Zero) at (prev + 0, 19) to (start + 0, 25)
 - Code(Zero) at (prev + 1, 9) to (start + 0, 15)
 - Code(Zero) at (prev + 2, 1) to (start + 0, 2)
+Highest counter ID seen: (none)

--- a/tests/coverage/unused_mod.cov-map
+++ b/tests/coverage/unused_mod.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 4, 1) to (start + 2, 2)
+Highest counter ID seen: c0

 Function name: unused_mod::unused_module::never_called_function (unused)
 Raw bytes (9): 0x[01, 01, 00, 01, 00, 02, 01, 02, 02]
@ -13,4 +14,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Zero) at (prev + 2, 1) to (start + 2, 2)
+Highest counter ID seen: (none)

--- a/tests/coverage/uses_crate.cov-map
+++ b/tests/coverage/uses_crate.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 27, 1) to (start + 2, 2)
+Highest counter ID seen: c0

 Function name: used_crate::used_only_from_bin_crate_generic_function::<&alloc::vec::Vec<i32>>
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 13, 01, 02, 02]
@ -13,6 +14,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 19, 1) to (start + 2, 2)
+Highest counter ID seen: c0

 Function name: used_crate::used_only_from_bin_crate_generic_function::<&str>
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 13, 01, 02, 02]
@ -21,6 +23,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 19, 1) to (start + 2, 2)
+Highest counter ID seen: c0

 Function name: used_crate::used_with_same_type_from_bin_crate_and_lib_crate_generic_function::<&str>
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 1f, 01, 02, 02]
@ -29,6 +32,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 31, 1) to (start + 2, 2)
+Highest counter ID seen: c0

 Function name: uses_crate::main
 Raw bytes (9): 0x[01, 02, 00, 01, 01, 0c, 01, 07, 02]
@ -37,4 +41,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 12, 1) to (start + 7, 2)
+Highest counter ID seen: c0

--- a/tests/coverage/uses_inline_crate.cov-map
+++ b/tests/coverage/uses_inline_crate.cov-map
@ -5,6 +5,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 44, 1) to (start + 2, 2)
+Highest counter ID seen: c0

 Function name: used_inline_crate::used_inline_function
 Raw bytes (26): 0x[01, 01, 01, 01, 05, 04, 01, 14, 01, 06, 0f, 05, 06, 10, 02, 06, 02, 02, 06, 00, 07, 01, 01, 05, 01, 02]
@ -18,6 +19,7 @@ Number of file 0 mappings: 4
 - Code(Expression(0, Sub)) at (prev + 2, 6) to (start + 0, 7)
    = (c0 - c1)
 - Code(Counter(0)) at (prev + 1, 5) to (start + 1, 2)
+Highest counter ID seen: c1

 Function name: used_inline_crate::used_only_from_bin_crate_generic_function::<&alloc::vec::Vec<i32>>
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 21, 01, 02, 02]
@ -26,6 +28,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 33, 1) to (start + 2, 2)
+Highest counter ID seen: c0

 Function name: used_inline_crate::used_only_from_bin_crate_generic_function::<&str>
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 21, 01, 02, 02]
@ -34,6 +37,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 33, 1) to (start + 2, 2)
+Highest counter ID seen: c0

 Function name: used_inline_crate::used_with_same_type_from_bin_crate_and_lib_crate_generic_function::<&str>
 Raw bytes (9): 0x[01, 01, 00, 01, 01, 31, 01, 02, 02]
@ -42,6 +46,7 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 49, 1) to (start + 2, 2)
+Highest counter ID seen: c0

 Function name: uses_inline_crate::main
 Raw bytes (9): 0x[01, 02, 00, 01, 01, 0c, 01, 0a, 02]
@ -50,4 +55,5 @@ Number of files: 1
 Number of expressions: 0
 Number of file 0 mappings: 1
 - Code(Counter(0)) at (prev + 12, 1) to (start + 10, 2)
+Highest counter ID seen: c0

--- a/tests/coverage/while.cov-map
+++ b/tests/coverage/while.cov-map
@ -10,4 +10,5 @@ Number of file 0 mappings: 4
    = (c0 + Zero)
 - Code(Zero) at (prev + 0, 21) to (start + 2, 6)
 - Code(Counter(0)) at (prev + 3, 1) to (start + 0, 2)
+Highest counter ID seen: c0

--- a/tests/coverage/while_early_ret.cov-map
+++ b/tests/coverage/while_early_ret.cov-map
@ -23,4 +23,5 @@ Number of file 0 mappings: 9
 - Code(Counter(2)) at (prev + 6, 5) to (start + 0, 11)
 - Code(Expression(4, Add)) at (prev + 1, 1) to (start + 0, 2)
    = ((c3 + c4) + c2)
+Highest counter ID seen: c4

--- a/tests/coverage/yield.cov-map
+++ b/tests/coverage/yield.cov-map
@ -39,6 +39,7 @@ Number of file 0 mappings: 16
 - Code(Expression(10, Add)) at (prev + 1, 14) to (start + 0, 52)
    = (c9 + c10)
 - Code(Counter(11)) at (prev + 2, 1) to (start + 0, 2)
+Highest counter ID seen: c11

 Function name: yield::main::{closure#0}
 Raw bytes (14): 0x[01, 01, 00, 02, 01, 09, 08, 01, 10, 05, 02, 10, 01, 06]
@ -48,6 +49,7 @@ Number of expressions: 0
 Number of file 0 mappings: 2
 - Code(Counter(0)) at (prev + 9, 8) to (start + 1, 16)
 - Code(Counter(1)) at (prev + 2, 16) to (start + 1, 6)
+Highest counter ID seen: c1

 Function name: yield::main::{closure#1}
 Raw bytes (24): 0x[01, 01, 00, 04, 01, 18, 08, 01, 10, 05, 02, 09, 00, 10, 09, 01, 09, 00, 10, 0d, 01, 10, 01, 06]
@ -59,4 +61,5 @@ Number of file 0 mappings: 4
 - Code(Counter(1)) at (prev + 2, 9) to (start + 0, 16)
 - Code(Counter(2)) at (prev + 1, 9) to (start + 0, 16)
 - Code(Counter(3)) at (prev + 1, 16) to (start + 1, 6)
+Highest counter ID seen: c3