From 396022b90b315ab35be3317836528d83bdd0c042 Mon Sep 17 00:00:00 2001
From: Ryan Levick <ryan.levick@gmail.com>
Date: Fri, 8 Jan 2021 10:00:39 +0100
Subject: [PATCH] Visit more targets when checking attrs

---
 compiler/rustc_hir/src/target.rs              |  2 ++
 compiler/rustc_passes/src/check_attr.rs       | 28 +++++++++++--------
 .../ui/proc-macro/ambiguous-builtin-attrs.rs  |  2 +-
 .../proc-macro/ambiguous-builtin-attrs.stderr | 10 +++----
 4 files changed, 25 insertions(+), 17 deletions(-)

diff --git a/compiler/rustc_hir/src/target.rs b/compiler/rustc_hir/src/target.rs
index 6dbcfb963ee..473477bf22d 100644
--- a/compiler/rustc_hir/src/target.rs
+++ b/compiler/rustc_hir/src/target.rs
@@ -54,6 +54,7 @@ pub enum Target {
     ForeignTy,
     GenericParam(GenericParamKind),
     MacroDef,
+    Param,
 }
 
 impl Display for Target {
@@ -96,6 +97,7 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
                     GenericParamKind::Const => "const parameter",
                 },
                 Target::MacroDef => "macro def",
+                Target::Param => "function param",
             }
         )
     }
diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
index 0e3a722e082..2c79eeeb0e6 100644
--- a/compiler/rustc_passes/src/check_attr.rs
+++ b/compiler/rustc_passes/src/check_attr.rs
@@ -1101,17 +1101,6 @@ fn visit_arm(&mut self, arm: &'tcx hir::Arm<'tcx>) {
         intravisit::walk_arm(self, arm);
     }
 
-    fn visit_macro_def(&mut self, macro_def: &'tcx hir::MacroDef<'tcx>) {
-        self.check_attributes(
-            macro_def.hir_id,
-            &macro_def.attrs,
-            &macro_def.span,
-            Target::MacroDef,
-            None,
-        );
-        intravisit::walk_macro_def(self, macro_def);
-    }
-
     fn visit_foreign_item(&mut self, f_item: &'tcx ForeignItem<'tcx>) {
         let target = Target::from_foreign_item(f_item);
         self.check_attributes(
@@ -1157,6 +1146,23 @@ fn visit_variant(
         self.check_attributes(variant.id, variant.attrs, &variant.span, Target::Variant, None);
         intravisit::walk_variant(self, variant, generics, item_id)
     }
+
+    fn visit_macro_def(&mut self, macro_def: &'tcx hir::MacroDef<'tcx>) {
+        self.check_attributes(
+            macro_def.hir_id,
+            macro_def.attrs,
+            &macro_def.span,
+            Target::MacroDef,
+            None,
+        );
+        intravisit::walk_macro_def(self, macro_def);
+    }
+
+    fn visit_param(&mut self, param: &'tcx hir::Param<'tcx>) {
+        self.check_attributes(param.hir_id, param.attrs, &param.span, Target::Param, None);
+
+        intravisit::walk_param(self, param);
+    }
 }
 
 fn is_c_like_enum(item: &Item<'_>) -> bool {
diff --git a/src/test/ui/proc-macro/ambiguous-builtin-attrs.rs b/src/test/ui/proc-macro/ambiguous-builtin-attrs.rs
index a6e9ed14ff1..65d8bcd9972 100644
--- a/src/test/ui/proc-macro/ambiguous-builtin-attrs.rs
+++ b/src/test/ui/proc-macro/ambiguous-builtin-attrs.rs
@@ -3,8 +3,8 @@
 #![feature(decl_macro)] //~ ERROR `feature` is ambiguous
 
 extern crate builtin_attrs;
-use builtin_attrs::{test, bench};
 use builtin_attrs::*;
+use builtin_attrs::{bench, test};
 
 #[repr(C)] //~ ERROR `repr` is ambiguous
 struct S;
diff --git a/src/test/ui/proc-macro/ambiguous-builtin-attrs.stderr b/src/test/ui/proc-macro/ambiguous-builtin-attrs.stderr
index 31959248a68..1ad991db3be 100644
--- a/src/test/ui/proc-macro/ambiguous-builtin-attrs.stderr
+++ b/src/test/ui/proc-macro/ambiguous-builtin-attrs.stderr
@@ -12,7 +12,7 @@ LL | #[repr(C)]
    |
    = note: `repr` could refer to a built-in attribute
 note: `repr` could also refer to the attribute macro imported here
-  --> $DIR/ambiguous-builtin-attrs.rs:7:5
+  --> $DIR/ambiguous-builtin-attrs.rs:6:5
    |
 LL | use builtin_attrs::*;
    |     ^^^^^^^^^^^^^^^^
@@ -26,7 +26,7 @@ LL | #[cfg_attr(all(), repr(C))]
    |
    = note: `repr` could refer to a built-in attribute
 note: `repr` could also refer to the attribute macro imported here
-  --> $DIR/ambiguous-builtin-attrs.rs:7:5
+  --> $DIR/ambiguous-builtin-attrs.rs:6:5
    |
 LL | use builtin_attrs::*;
    |     ^^^^^^^^^^^^^^^^
@@ -40,7 +40,7 @@ LL | fn non_macro_expanded_location<#[repr(C)] T>() {
    |
    = note: `repr` could refer to a built-in attribute
 note: `repr` could also refer to the attribute macro imported here
-  --> $DIR/ambiguous-builtin-attrs.rs:7:5
+  --> $DIR/ambiguous-builtin-attrs.rs:6:5
    |
 LL | use builtin_attrs::*;
    |     ^^^^^^^^^^^^^^^^
@@ -54,7 +54,7 @@ LL |         #[repr(C)]
    |
    = note: `repr` could refer to a built-in attribute
 note: `repr` could also refer to the attribute macro imported here
-  --> $DIR/ambiguous-builtin-attrs.rs:7:5
+  --> $DIR/ambiguous-builtin-attrs.rs:6:5
    |
 LL | use builtin_attrs::*;
    |     ^^^^^^^^^^^^^^^^
@@ -82,7 +82,7 @@ LL | #![feature(decl_macro)]
    |
    = note: `feature` could refer to a built-in attribute
 note: `feature` could also refer to the attribute macro imported here
-  --> $DIR/ambiguous-builtin-attrs.rs:7:5
+  --> $DIR/ambiguous-builtin-attrs.rs:6:5
    |
 LL | use builtin_attrs::*;
    |     ^^^^^^^^^^^^^^^^