Revert some `span_bug`s to `span_delayed_bug`.

Fixes #121410.
Fixes #121414.
Fixes #121418.
Fixes #121431.

compiler/rustc_ast_lowering/src/lib.rs

@@ -1636,7 +1636,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                     if let Some(old_def_id) = self.orig_opt_local_def_id(param) {
                         old_def_id
                     } else {
-                        self.dcx().span_bug(lifetime.ident.span, "no def-id for fresh lifetime");
+                        self.dcx()
+                            .span_delayed_bug(lifetime.ident.span, "no def-id for fresh lifetime");
+                        continue;
                     }
                 }
 

compiler/rustc_hir_analysis/src/collect/generics_of.rs

@@ -315,7 +315,7 @@ pub(super) fn generics_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Generics {
 
             if is_host_effect {
                 if let Some(idx) = host_effect_index {
-                    tcx.dcx().span_bug(
+                    tcx.dcx().span_delayed_bug(
                         param.span,
                         format!("parent also has host effect param? index: {idx}, def: {def_id:?}"),
                     );

compiler/rustc_hir_typeck/src/mem_categorization.rs

@@ -582,7 +582,8 @@ impl<'a, 'tcx> MemCategorizationContext<'a, 'tcx> {
         match ty.kind() {
             ty::Tuple(args) => Ok(args.len()),
             _ => {
-                self.tcx().dcx().span_bug(span, "tuple pattern not applied to a tuple");
+                self.tcx().dcx().span_delayed_bug(span, "tuple pattern not applied to a tuple");
+                Err(())
             }
         }
     }

compiler/rustc_trait_selection/src/traits/mod.rs

@@ -172,9 +172,7 @@ fn do_normalize_predicates<'tcx>(
     // the normalized predicates.
     let errors = infcx.resolve_regions(&outlives_env);
     if !errors.is_empty() {
-        // @lcnr: Let's still ICE here for now. I want a test case
-        // for that.
-        tcx.dcx().span_bug(
+        tcx.dcx().span_delayed_bug(
             span,
             format!("failed region resolution while normalizing {elaborated_env:?}: {errors:?}"),
         );

tests/ui/lowering/span-bug-issue-121431.rs

@@ -0,0 +1,4 @@
+fn bug<T>() -> impl CallbackMarker< Item = [(); { |_: &mut ()| 3; 4 }] > {}
+//~^ ERROR cannot find trait `CallbackMarker` in this scope
+
+fn main() {}

tests/ui/lowering/span-bug-issue-121431.stderr

@@ -0,0 +1,9 @@
+error[E0405]: cannot find trait `CallbackMarker` in this scope
+  --> $DIR/span-bug-issue-121431.rs:1:21
+   |
+LL | fn bug<T>() -> impl CallbackMarker< Item = [(); { |_: &mut ()| 3; 4 }] > {}
+   |                     ^^^^^^^^^^^^^^ not found in this scope
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0405`.

tests/ui/rfcs/rfc-2632-const-trait-impl/effects/span-bug-issue-121418.rs

@@ -0,0 +1,13 @@
+#![feature(const_trait_impl)]
+#![feature(effects)]
+
+struct S;
+trait T {}
+
+impl const dyn T {
+    //~^ ERROR inherent impls cannot be `const`
+    //~| ERROR the const parameter `host` is not constrained by the impl trait, self type, or
+    pub const fn new() -> std::sync::Mutex<dyn T> {}
+}
+
+fn main() {}

tests/ui/rfcs/rfc-2632-const-trait-impl/effects/span-bug-issue-121418.stderr

@@ -0,0 +1,22 @@
+error: inherent impls cannot be `const`
+  --> $DIR/span-bug-issue-121418.rs:7:12
+   |
+LL | impl const dyn T {
+   |      ----- ^^^^^ inherent impl for this type
+   |      |
+   |      `const` because of this
+   |
+   = note: only trait implementations may be annotated with `const`
+
+error[E0207]: the const parameter `host` is not constrained by the impl trait, self type, or predicates
+  --> $DIR/span-bug-issue-121418.rs:7:6
+   |
+LL | impl const dyn T {
+   |      ^^^^^ unconstrained const parameter
+   |
+   = note: expressions using a const parameter must map each value to a distinct output value
+   = note: proving the result of expressions other than the parameter are unique is not supported
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0207`.

tests/ui/traits/span-bug-issue-121414.rs

@@ -0,0 +1,15 @@
+trait Bar {
+    type Type;
+}
+struct Foo<'a>(&'a ());
+impl<'a> Bar for Foo<'f> { //~ ERROR undeclared lifetime
+    type Type = u32;
+}
+
+fn test() //~ ERROR implementation of `Bar` is not general enough
+where
+    for<'a> <Foo<'a> as Bar>::Type: Sized,
+{
+}
+
+fn main() {}

tests/ui/traits/span-bug-issue-121414.stderr

@@ -0,0 +1,20 @@
+error[E0261]: use of undeclared lifetime name `'f`
+  --> $DIR/span-bug-issue-121414.rs:5:22
+   |
+LL | impl<'a> Bar for Foo<'f> {
+   |      -               ^^ undeclared lifetime
+   |      |
+   |      help: consider introducing lifetime `'f` here: `'f,`
+
+error: implementation of `Bar` is not general enough
+  --> $DIR/span-bug-issue-121414.rs:9:4
+   |
+LL | fn test()
+   |    ^^^^ implementation of `Bar` is not general enough
+   |
+   = note: `Bar` would have to be implemented for the type `Foo<'0>`, for any lifetime `'0`...
+   = note: ...but `Bar` is actually implemented for the type `Foo<'1>`, for some specific lifetime `'1`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0261`.

tests/ui/typeck/span-bug-issue-121410.rs

@@ -0,0 +1,15 @@
+fn test_missing_unsafe_warning_on_repr_packed() {
+    struct Foo {
+        x: String,
+    }
+
+    let foo = Foo { x: String::new() };
+
+    let c = || {
+        let (_, t2) = foo.x; //~ ERROR mismatched types
+    };
+
+    c();
+}
+
+fn main() {}

tests/ui/typeck/span-bug-issue-121410.stderr

@@ -0,0 +1,14 @@
+error[E0308]: mismatched types
+  --> $DIR/span-bug-issue-121410.rs:9:13
+   |
+LL |         let (_, t2) = foo.x;
+   |             ^^^^^^^   ----- this expression has type `String`
+   |             |
+   |             expected `String`, found `(_, _)`
+   |
+   = note: expected struct `String`
+               found tuple `(_, _)`
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0308`.