Use counter intead of two Options

rust-lang · Mar 17, 2024 · 04c966b · 04c966b
1 parent fe143a2
commit 04c966b
Showing 1 changed file with 12 additions and 31 deletions.
diff --git a/compiler/rustc_hir_typeck/src/pat.rs b/compiler/rustc_hir_typeck/src/pat.rs
@@ -84,8 +84,8 @@ struct PatInfo<'tcx, 'a> {
     top_info: TopInfo<'tcx>,
     decl_origin: Option<DeclOrigin<'a>>,
 
-    parent_kind: Option<PatKind<'tcx>>,
-    current_kind: Option<PatKind<'tcx>>,
+    /// The depth of current pattern
+    current_depth: u32,
 }
 
 impl<'tcx> FnCtxt<'_, 'tcx> {
@@ -155,13 +155,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         decl_origin: Option<DeclOrigin<'tcx>>,
     ) {
         let info = TopInfo { expected, origin_expr, span };
-        let pat_info = PatInfo {
-            binding_mode: INITIAL_BM,
-            top_info: info,
-            decl_origin,
-            parent_kind: None,
-            current_kind: None,
-        };
+        let pat_info =
+            PatInfo { binding_mode: INITIAL_BM, top_info: info, decl_origin, current_depth: 0 };
         self.check_pat(pat, expected, pat_info);
     }
 
@@ -172,7 +167,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     /// Conversely, inside this module, `check_pat_top` should never be used.
     #[instrument(level = "debug", skip(self, pat_info))]
     fn check_pat(&self, pat: &'tcx Pat<'tcx>, expected: Ty<'tcx>, pat_info: PatInfo<'tcx, '_>) {
-        let PatInfo { binding_mode: def_bm, top_info: ti, current_kind, .. } = pat_info;
+        let PatInfo { binding_mode: def_bm, top_info: ti, current_depth, .. } = pat_info;
 
         let path_res = match &pat.kind {
             PatKind::Path(qpath) => Some(
@@ -186,8 +181,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             binding_mode: def_bm,
             top_info: ti,
             decl_origin: pat_info.decl_origin,
-            parent_kind: current_kind,
-            current_kind: Some(pat.kind),
+            current_depth: current_depth + 1,
         };
 
         let ty = match pat.kind {
@@ -1061,21 +1055,14 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         expected: Ty<'tcx>,
         pat_info: PatInfo<'tcx, '_>,
     ) -> Ty<'tcx> {
-        let PatInfo { binding_mode: def_bm, top_info: ti, decl_origin, parent_kind, current_kind } =
-            pat_info;
+        let PatInfo { binding_mode: def_bm, top_info: ti, decl_origin, current_depth } = pat_info;
         let tcx = self.tcx;
         let on_error = |e| {
             for pat in subpats {
                 self.check_pat(
                     pat,
                     Ty::new_error(tcx, e),
-                    PatInfo {
-                        binding_mode: def_bm,
-                        top_info: ti,
-                        decl_origin,
-                        parent_kind,
-                        current_kind,
-                    },
+                    PatInfo { binding_mode: def_bm, top_info: ti, decl_origin, current_depth },
                 );
             }
         };
@@ -1142,13 +1129,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 self.check_pat(
                     subpat,
                     field_ty,
-                    PatInfo {
-                        binding_mode: def_bm,
-                        top_info: ti,
-                        decl_origin,
-                        parent_kind,
-                        current_kind,
-                    },
+                    PatInfo { binding_mode: def_bm, top_info: ti, decl_origin, current_depth },
                 );
 
                 self.tcx.check_stability(
@@ -2303,7 +2284,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         expected_ty: Ty<'tcx>,
         pat_info: PatInfo<'tcx, '_>,
     ) -> ErrorGuaranteed {
-        let PatInfo { top_info: ti, parent_kind, .. } = pat_info;
+        let PatInfo { top_info: ti, current_depth, .. } = pat_info;
 
         let mut err = struct_span_code_err!(
             self.dcx(),
@@ -2341,8 +2322,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 _ => (),
             }
 
-            let enclosure_is_struct = parent_kind.is_some();
-            if is_slice_or_array_or_vector && !enclosure_is_struct {
+            let is_top_level = current_depth <= 1;
+            if is_slice_or_array_or_vector && is_top_level {
                 err.span_suggestion(
                     span,
                     "consider slicing here",