Rollup merge of #134989 - max-niederman:guard-patterns-hir, r=oli-obk

Lower Guard Patterns to HIR.

Implements lowering of [guard patterns](https://rust-lang.github.io/rfcs/3637-guard-patterns.html) (see the [tracking issue](#129967)) to HIR.

clippy_lints/src/equatable_if_let.rs

@@ -55,7 +55,7 @@ fn unary_pattern(pat: &Pat<'_>) -> bool {
         | PatKind::Err(_) => false,
         PatKind::Struct(_, a, etc) => !etc && a.iter().all(|x| unary_pattern(x.pat)),
         PatKind::Tuple(a, etc) | PatKind::TupleStruct(_, a, etc) => etc.as_opt_usize().is_none() && array_rec(a),
-        PatKind::Ref(x, _) | PatKind::Box(x) | PatKind::Deref(x) => unary_pattern(x),
+        PatKind::Ref(x, _) | PatKind::Box(x) | PatKind::Deref(x) | PatKind::Guard(x, _) => unary_pattern(x),
         PatKind::Path(_) | PatKind::Lit(_) => true,
     }
 }

clippy_lints/src/matches/match_same_arms.rs

@@ -254,9 +254,11 @@ impl<'a> NormalizedPat<'a> {
     fn from_pat(cx: &LateContext<'_>, arena: &'a DroplessArena, pat: &'a Pat<'_>) -> Self {
         match pat.kind {
             PatKind::Wild | PatKind::Binding(.., None) => Self::Wild,
-            PatKind::Binding(.., Some(pat)) | PatKind::Box(pat) | PatKind::Deref(pat) | PatKind::Ref(pat, _) => {
-                Self::from_pat(cx, arena, pat)
-            },
+            PatKind::Binding(.., Some(pat))
+            | PatKind::Box(pat)
+            | PatKind::Deref(pat)
+            | PatKind::Ref(pat, _)
+            | PatKind::Guard(pat, _) => Self::from_pat(cx, arena, pat),
             PatKind::Never => Self::Never,
             PatKind::Struct(ref path, fields, _) => {
                 let fields =

clippy_lints/src/matches/single_match.rs

@@ -343,6 +343,10 @@ impl<'a> PatState<'a> {
                 matches!(self, Self::Wild)
             },
 
+            PatKind::Guard(..) => {
+                matches!(self, Self::Wild)
+            }
+
             // Patterns for things which can only contain a single sub-pattern.
             PatKind::Binding(_, _, _, Some(pat)) | PatKind::Ref(pat, _) | PatKind::Box(pat) | PatKind::Deref(pat) => {
                 self.add_pat(cx, pat)

clippy_lints/src/utils/author.rs

@@ -712,6 +712,12 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
                 kind!("Ref({pat}, Mutability::{muta:?})");
                 self.pat(pat);
             },
+            PatKind::Guard(pat, cond) => {
+                bind!(self, pat, cond);
+                kind!("Guard({pat}, {cond})");
+                self.pat(pat);
+                self.expr(cond);
+            }
             PatKind::Lit(lit_expr) => {
                 bind!(self, lit_expr);
                 kind!("Lit({lit_expr})");

clippy_utils/src/hir_utils.rs

@@ -1104,6 +1104,10 @@ impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
                 self.hash_pat(pat);
                 std::mem::discriminant(&mu).hash(&mut self.s);
             },
+            PatKind::Guard(pat, guard) => {
+                self.hash_pat(pat);
+                self.hash_expr(guard);
+            },
             PatKind::Slice(l, m, r) => {
                 for pat in l {
                     self.hash_pat(pat);

clippy_utils/src/lib.rs

@@ -1777,7 +1777,7 @@ pub fn is_refutable(cx: &LateContext<'_>, pat: &Pat<'_>) -> bool {
                 },
             }
         },
-        PatKind::Lit(..) | PatKind::Range(..) | PatKind::Err(_) | PatKind::Deref(_) => true,
+        PatKind::Lit(..) | PatKind::Range(..) | PatKind::Err(_) | PatKind::Deref(_) | PatKind::Guard(..) => true,
     }
 }