move to `complexity` but don't lint by default

book/src/lint_configuration.md

@@ -161,7 +161,7 @@ The maximum cognitive complexity a function can have
 ## `excessive-nesting-threshold`
 The maximum amount of nesting a block can reside in
 
-**Default Value:** `10` (`u64`)
+**Default Value:** `0` (`u64`)
 
 ---
 **Affected lints:**

clippy_lints/src/excessive_nesting.rs

@@ -11,13 +11,12 @@ use rustc_span::Span;
 
 declare_clippy_lint! {
     /// ### What it does
-    ///
     /// Checks for blocks which are nested beyond a certain threshold.
     ///
-    /// ### Why is this bad?
+    /// Note: Even though this lint is warn-by-default, it will only trigger if a maximum nesting level is defined in the clippy.toml file.
     ///
-    /// It can severely hinder readability. The default is very generous; if you
-    /// exceed this, it's a sign you should refactor.
+    /// ### Why is this bad?
+    /// It can severely hinder readability.
     ///
     /// ### Example
     /// An example clippy.toml configuration:
@@ -59,7 +58,7 @@ declare_clippy_lint! {
     /// ```
     #[clippy::version = "1.70.0"]
     pub EXCESSIVE_NESTING,
-    restriction,
+    complexity,
     "checks for blocks nested beyond a certain threshold"
 }
 impl_lint_pass!(ExcessiveNesting => [EXCESSIVE_NESTING]);
@@ -115,7 +114,9 @@ struct NestingVisitor<'conf, 'cx> {
 
 impl NestingVisitor<'_, '_> {
     fn check_indent(&mut self, span: Span, id: NodeId) -> bool {
-        if self.nest_level > self.conf.excessive_nesting_threshold && !in_external_macro(self.cx.sess(), span) {
+        let threshold = self.conf.excessive_nesting_threshold;
+
+        if threshold != 0 && self.nest_level > threshold && !in_external_macro(self.cx.sess(), span) {
             self.conf.nodes.insert(id);
 
             return true;

clippy_lints/src/utils/conf.rs

@@ -308,7 +308,7 @@ define_Conf! {
     /// Lint: EXCESSIVE_NESTING.
     ///
     /// The maximum amount of nesting a block can reside in
-    (excessive_nesting_threshold: u64 = 10),
+    (excessive_nesting_threshold: u64 = 0),
     /// DEPRECATED LINT: CYCLOMATIC_COMPLEXITY.
     ///
     /// Use the Cognitive Complexity lint instead.

tests/ui-toml/excessive_nesting/default/clippy.toml

@@ -1 +1 @@
-excessive-nesting-threshold = 10
+excessive-nesting-threshold = 0

tests/ui-toml/excessive_nesting/excessive_nesting.default.stderr

@@ -1,43 +0,0 @@
-error: this block is too nested
-  --> $DIR/excessive_nesting.rs:154:18
-   |
-LL |     [0, {{{{{{{{{{0}}}}}}}}}}];
-   |                  ^^^
-   |
-   = help: try refactoring your code to minimize nesting
-   = note: `-D clippy::excessive-nesting` implied by `-D warnings`
-
-error: this block is too nested
-  --> $DIR/excessive_nesting.rs:156:17
-   |
-LL |     xx[{{{{{{{{{{{{{{{{{{{{{{{{3}}}}}}}}}}}}}}}}}}}}}}}}];
-   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = help: try refactoring your code to minimize nesting
-
-error: this block is too nested
-  --> $DIR/excessive_nesting.rs:157:19
-   |
-LL |     &mut {{{{{{{{{{y}}}}}}}}}};
-   |                   ^^^
-   |
-   = help: try refactoring your code to minimize nesting
-
-error: this block is too nested
-  --> $DIR/excessive_nesting.rs:165:29
-   |
-LL |     let d = D { d: {{{{{{{{{{{{{{{{{{{{{{{3}}}}}}}}}}}}}}}}}}}}}}} };
-   |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = help: try refactoring your code to minimize nesting
-
-error: this block is too nested
-  --> $DIR/excessive_nesting.rs:168:27
-   |
-LL |     {{{{1;}}}}..={{{{{{{{{{{{{{{{{{{{{{{{{{6}}}}}}}}}}}}}}}}}}}}}}}}}};
-   |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = help: try refactoring your code to minimize nesting
-
-error: aborting due to 5 previous errors
-

tests/ui-toml/excessive_nesting/excessive_nesting.rs

@@ -1,6 +1,6 @@
 //@aux-build:macro_rules.rs
-//@revisions: below default
-//@[below] rustc-env:CLIPPY_CONF_DIR=tests/ui-toml/excessive_nesting/below
+//@revisions: set default
+//@[set] rustc-env:CLIPPY_CONF_DIR=tests/ui-toml/excessive_nesting/set
 //@[default] rustc-env:CLIPPY_CONF_DIR=tests/ui-toml/excessive_nesting/default
 #![rustfmt::skip]
 #![feature(custom_inner_attributes)]