Rename pattern_complexity attr as pattern_complexity_limit.

For consistency with `recursion_limit`, `move_size_limit`, and
`type_length_limit`.

compiler/rustc_feature/src/builtin_attrs.rs

@@ -1148,7 +1148,7 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
         "the `#[omit_gdb_pretty_printer_section]` attribute is just used for the Rust test suite",
     ),
     rustc_attr!(
-        TEST, pattern_complexity, CrateLevel, template!(NameValueStr: "N"),
+        TEST, pattern_complexity_limit, CrateLevel, template!(NameValueStr: "N"),
         ErrorFollowing, EncodeCrossCrate::No,
     ),
 ];

compiler/rustc_feature/src/unstable.rs

@@ -227,7 +227,7 @@ declare_features! (
     /// Allows using `#[omit_gdb_pretty_printer_section]`.
     (internal, omit_gdb_pretty_printer_section, "1.5.0", None),
     /// Set the maximum pattern complexity allowed (not limited by default).
-    (internal, pattern_complexity, "1.78.0", None),
+    (internal, pattern_complexity_limit, "1.78.0", None),
     /// Allows using pattern types.
     (internal, pattern_types, "1.79.0", Some(123646)),
     /// Allows using `#[prelude_import]` on glob `use` items.

compiler/rustc_interface/src/limits.rs

@@ -35,7 +35,7 @@ pub(crate) fn provide(providers: &mut Providers) {
         pattern_complexity_limit: get_limit(
             tcx.hir().krate_attrs(),
             tcx.sess,
-            sym::pattern_complexity,
+            sym::pattern_complexity_limit,
             Limit::unlimited(),
         ),
     }

compiler/rustc_span/src/symbol.rs

@@ -1495,7 +1495,7 @@ symbols! {
         path_main_separator,
         path_to_pathbuf,
         pathbuf_as_path,
-        pattern_complexity,
+        pattern_complexity_limit,
         pattern_parentheses,
         pattern_type,
         pattern_types,

src/tools/rust-analyzer/crates/ide-db/src/generated/lints.rs

@@ -9107,8 +9107,8 @@ The tracking issue for this feature is: [#27721]
         deny_since: None,
     },
     Lint {
-        label: "pattern_complexity",
-        description: r##"# `pattern_complexity`
+        label: "pattern_complexity_limit",
+        description: r##"# `pattern_complexity_limit`
 
 This feature has no tracking issue, and is therefore likely internal to the compiler, not being intended for general use.
 

tests/ui/feature-gates/feature-gate-pattern-complexity-limit.rs

@@ -0,0 +1,6 @@
+// check that `pattern_complexity_limit` is feature-gated
+
+#![pattern_complexity_limit = "42"]
+//~^ ERROR: the `#[pattern_complexity_limit]` attribute is just used for rustc unit tests
+
+fn main() {}

tests/ui/feature-gates/feature-gate-pattern-complexity.stderr → tests/ui/feature-gates/feature-gate-pattern-complexity-limit.stderr

@@ -1,8 +1,8 @@
-error[E0658]: the `#[pattern_complexity]` attribute is just used for rustc unit tests and will never be stable
-  --> $DIR/feature-gate-pattern-complexity.rs:3:1
+error[E0658]: the `#[pattern_complexity_limit]` attribute is just used for rustc unit tests and will never be stable
+  --> $DIR/feature-gate-pattern-complexity-limit.rs:3:1
    |
-LL | #![pattern_complexity = "42"]
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | #![pattern_complexity_limit = "42"]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: add `#![feature(rustc_attrs)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date

tests/ui/pattern/complexity_limit.rs

@@ -1,5 +1,5 @@
 #![feature(rustc_attrs)]
-#![pattern_complexity = "10000"]
+#![pattern_complexity_limit = "10000"]
 
 #[derive(Default)]
 struct BaseCommand {

tests/ui/pattern/usefulness/issue-118437-exponential-time-on-diagonal-match.rs

@@ -1,5 +1,5 @@
 #![feature(rustc_attrs)]
-#![pattern_complexity = "61"]
+#![pattern_complexity_limit = "61"]
 
 //@ check-pass
 struct BaseCommand {