Remove redundant check for #[loop_match] and #[const_continue]

compiler/rustc_attr_parsing/src/attributes/loop_match.rs

@@ -13,7 +13,7 @@ impl NoArgsAttributeParser for LoopMatchParser {
 pub(crate) struct ConstContinueParser;
 impl NoArgsAttributeParser for ConstContinueParser {
     const PATH: &[Symbol] = &[sym::const_continue];
-    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Expression)]);
+    const ALLOWED_TARGETS: AllowedTargets = AllowedTargets::AllowList(&[Allow(Target::Break)]);
     const STABILITY: AttributeStability = unstable!(loop_match);
     const CREATE: fn(Span) -> AttributeKind = AttributeKind::ConstContinue;
 }

compiler/rustc_attr_parsing/src/target_checking.rs

@@ -527,5 +527,6 @@ pub(crate) const ALL_TARGETS: &'static [Policy] = {
         Allow(Target::Loop),
         Allow(Target::ForLoop),
         Allow(Target::While),
+        Allow(Target::Break),
     ]
 };

compiler/rustc_hir/src/target.rs

@@ -70,6 +70,7 @@ pub enum Target {
     ForLoop,
     While,
     Loop,
+    Break,
 }
 
 impl Display for Target {
@@ -119,7 +120,8 @@ impl Target {
             | Target::Delegation { .. }
             | Target::Loop
             | Target::While
-            | Target::ForLoop => false,
+            | Target::ForLoop
+            | Target::Break => false,
         }
     }
 
@@ -265,6 +267,7 @@ impl Target {
             ast::ExprKind::ForLoop { .. } => Self::ForLoop,
             ast::ExprKind::Loop(..) => Self::Loop,
             ast::ExprKind::While(..) => Self::While,
+            ast::ExprKind::Break(..) => Self::Break,
             _ => Self::Expression,
         }
     }
@@ -319,6 +322,7 @@ impl Target {
             Target::Loop => "loop",
             Target::ForLoop => "for loop",
             Target::While => "while loop",
+            Target::Break => "break expression",
         }
     }
 
@@ -373,6 +377,7 @@ impl Target {
             Target::ForLoop => "for loops",
             Target::Loop => "loops",
             Target::While => "while loops",
+            Target::Break => "break expressions",
         }
     }
 }

compiler/rustc_passes/src/check_attr.rs

@@ -193,12 +193,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
             AttributeKind::Inline(kind, attr_span) => {
                 self.check_inline(hir_id, *attr_span, kind, target)
             }
-            AttributeKind::LoopMatch(attr_span) => {
-                self.check_loop_match(hir_id, *attr_span, target)
-            }
-            AttributeKind::ConstContinue(attr_span) => {
-                self.check_const_continue(hir_id, *attr_span, target)
-            }
             AttributeKind::AllowInternalUnsafe(attr_span)
             | AttributeKind::AllowInternalUnstable(.., attr_span) => {
                 self.check_macro_only_attr(*attr_span, span, target, attrs)
@@ -218,7 +212,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
             &AttributeKind::RustcPubTransparent(attr_span) => {
                 self.check_rustc_pub_transparent(attr_span, span, attrs)
             }
-            AttributeKind::RustcAlign { .. } => {}
             AttributeKind::Naked(..) => self.check_naked(hir_id, target),
             AttributeKind::TrackCaller(attr_span) => {
                 self.check_track_caller(hir_id, *attr_span, attrs, target)
@@ -262,6 +255,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
             AttributeKind::Cold => (),
             AttributeKind::CollapseDebugInfo(..) => (),
             AttributeKind::CompilerBuiltins => (),
+            AttributeKind::ConstContinue(..) => {}
             AttributeKind::Coroutine => (),
             AttributeKind::Coverage(..) => (),
             AttributeKind::CrateName { .. } => (),
@@ -286,6 +280,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
             AttributeKind::LinkOrdinal { .. } => (),
             AttributeKind::LinkSection { .. } => (),
             AttributeKind::Linkage(..) => (),
+            AttributeKind::LoopMatch(..) => {}
             AttributeKind::MacroEscape => (),
             AttributeKind::MacroUse { .. } => (),
             AttributeKind::Marker => (),
@@ -317,6 +312,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
             // handled below this loop and elsewhere
             AttributeKind::Repr { .. } => (),
             AttributeKind::RustcAbi { .. } => (),
+            AttributeKind::RustcAlign { .. } => {}
             AttributeKind::RustcAllocator => (),
             AttributeKind::RustcAllocatorZeroed => (),
             AttributeKind::RustcAllocatorZeroedVariant { .. } => (),
@@ -891,7 +887,8 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
             | Target::Delegation { .. }
             | Target::Loop
             | Target::ForLoop
-            | Target::While => None,
+            | Target::While
+            | Target::Break => None,
         } {
             self.tcx.dcx().emit_err(diagnostics::DocAliasBadLocation { span, location });
             return;
@@ -1662,30 +1659,6 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                 .emit_err(diagnostics::BothOptimizeNoneAndInline { optimize_span, inline_span });
         }
     }
-
-    fn check_loop_match(&self, hir_id: HirId, attr_span: Span, target: Target) {
-        let node_span = self.tcx.hir_span(hir_id);
-
-        if !matches!(target, Target::Expression) {
-            return; // Handled in target checking during attr parse
-        }
-
-        if !matches!(self.tcx.hir_expect_expr(hir_id).kind, hir::ExprKind::Loop(..)) {
-            self.dcx().emit_err(diagnostics::LoopMatchAttr { attr_span, node_span });
-        };
-    }
-
-    fn check_const_continue(&self, hir_id: HirId, attr_span: Span, target: Target) {
-        let node_span = self.tcx.hir_span(hir_id);
-
-        if !matches!(target, Target::Expression) {
-            return; // Handled in target checking during attr parse
-        }
-
-        if !matches!(self.tcx.hir_expect_expr(hir_id).kind, hir::ExprKind::Break(..)) {
-            self.dcx().emit_err(diagnostics::ConstContinueAttr { attr_span, node_span });
-        };
-    }
 }
 
 impl<'tcx> Visitor<'tcx> for CheckAttrVisitor<'tcx> {

compiler/rustc_passes/src/diagnostics.rs

@@ -13,24 +13,6 @@ use rustc_span::{DUMMY_SP, Ident, Span, Symbol};
 use crate::check_attr::ProcMacroKind;
 use crate::lang_items::Duplicate;
 
-#[derive(Diagnostic)]
-#[diag("`#[loop_match]` should be applied to a loop")]
-pub(crate) struct LoopMatchAttr {
-    #[primary_span]
-    pub attr_span: Span,
-    #[label("not a loop")]
-    pub node_span: Span,
-}
-
-#[derive(Diagnostic)]
-#[diag("`#[const_continue]` should be applied to a break expression")]
-pub(crate) struct ConstContinueAttr {
-    #[primary_span]
-    pub attr_span: Span,
-    #[label("not a break expression")]
-    pub node_span: Span,
-}
-
 #[derive(Diagnostic)]
 #[diag("`{$no_mangle_attr}` attribute may not be used in combination with `{$export_name_attr}`")]
 pub(crate) struct MixedExportNameAndNoMangle {

tests/ui/loop-match/invalid-attribute.rs

@@ -37,8 +37,8 @@ fn main() {
 
     {
         #[loop_match] //~ ERROR attribute cannot be used on
-        //~^ ERROR `#[loop_match]` should be applied to a loop
-        #[const_continue] //~ ERROR should be applied to a break expression
+        #[const_continue]
+        //~^ ERROR `#[const_continue]` attribute cannot be used on expressions
         5
     };
 }

tests/ui/loop-match/invalid-attribute.stderr

@@ -12,7 +12,7 @@ error: `#[const_continue]` attribute cannot be used on crates
 LL | #![const_continue]
    | ^^^^^^^^^^^^^^^^^^
    |
-   = help: `#[const_continue]` can be applied to 
+   = help: `#[const_continue]` can only be applied to break expressions
 
 error: `#[loop_match]` attribute cannot be used on foreign functions
   --> $DIR/invalid-attribute.rs:10:5
@@ -28,7 +28,7 @@ error: `#[const_continue]` attribute cannot be used on foreign functions
 LL |     #[const_continue]
    |     ^^^^^^^^^^^^^^^^^
    |
-   = help: `#[const_continue]` can be applied to 
+   = help: `#[const_continue]` can only be applied to break expressions
 
 error: `#[loop_match]` attribute cannot be used on structs
   --> $DIR/invalid-attribute.rs:15:1
@@ -44,7 +44,7 @@ error: `#[const_continue]` attribute cannot be used on structs
 LL | #[const_continue]
    | ^^^^^^^^^^^^^^^^^
    |
-   = help: `#[const_continue]` can be applied to 
+   = help: `#[const_continue]` can only be applied to break expressions
 
 error: `#[loop_match]` attribute cannot be used on required trait methods
   --> $DIR/invalid-attribute.rs:24:5
@@ -60,7 +60,7 @@ error: `#[const_continue]` attribute cannot be used on required trait methods
 LL |     #[const_continue]
    |     ^^^^^^^^^^^^^^^^^
    |
-   = help: `#[const_continue]` can be applied to 
+   = help: `#[const_continue]` can only be applied to break expressions
 
 error: `#[loop_match]` attribute cannot be used on functions
   --> $DIR/invalid-attribute.rs:29:1
@@ -76,7 +76,7 @@ error: `#[const_continue]` attribute cannot be used on functions
 LL | #[const_continue]
    | ^^^^^^^^^^^^^^^^^
    |
-   = help: `#[const_continue]` can be applied to 
+   = help: `#[const_continue]` can only be applied to break expressions
 
 error: `#[loop_match]` attribute cannot be used on closures
   --> $DIR/invalid-attribute.rs:34:5
@@ -92,7 +92,7 @@ error: `#[const_continue]` attribute cannot be used on closures
 LL |     #[const_continue]
    |     ^^^^^^^^^^^^^^^^^
    |
-   = help: `#[const_continue]` can be applied to 
+   = help: `#[const_continue]` can only be applied to break expressions
 
 error: `#[loop_match]` attribute cannot be used on expressions
   --> $DIR/invalid-attribute.rs:39:9
@@ -102,22 +102,13 @@ LL |         #[loop_match]
    |
    = help: `#[loop_match]` can only be applied to loops
 
-error: `#[loop_match]` should be applied to a loop
-  --> $DIR/invalid-attribute.rs:39:9
-   |
-LL |         #[loop_match]
-   |         ^^^^^^^^^^^^^
-...
-LL |         5
-   |         - not a loop
-
-error: `#[const_continue]` should be applied to a break expression
-  --> $DIR/invalid-attribute.rs:41:9
+error: `#[const_continue]` attribute cannot be used on expressions
+  --> $DIR/invalid-attribute.rs:40:9
    |
 LL |         #[const_continue]
    |         ^^^^^^^^^^^^^^^^^
-LL |         5
-   |         - not a break expression
+   |
+   = help: `#[const_continue]` can only be applied to break expressions
 
-error: aborting due to 15 previous errors
+error: aborting due to 14 previous errors