[PATCH] D52400: Improve -Wshadow warnings with enumerators

[Aaron Ballman via Phabricator via cfe-commits]

aaron.ballman created this revision.
aaron.ballman added reviewers: rsmith, dblaikie.

Currently, we do not check for enumerators that shadow other enumerators as part of -Wshadow, but gcc does provide such a diagnostic for this case.  This is intended to catch shadowing issues like:

  enum E1{e1};
  void f(void) {
    enum E2{e1};
  }

This patch addresses PR24718.


https://reviews.llvm.org/D52400

Files:
  lib/Sema/SemaDecl.cpp
  test/Sema/warn-shadow.c


Index: test/Sema/warn-shadow.c
===================================================================
--- test/Sema/warn-shadow.c
+++ test/Sema/warn-shadow.c
@@ -59,3 +59,8 @@
 void test8() {
   int bob; // expected-warning {{declaration shadows a variable in the global scope}}
 }
+
+enum PR24718_1{pr24718}; // expected-note {{previous declaration is here}}
+void PR24718(void) {
+  enum PR24718_2{pr24718}; // expected-warning {{declaration shadows a variable in the global scope}}
+}
Index: lib/Sema/SemaDecl.cpp
===================================================================
--- lib/Sema/SemaDecl.cpp
+++ lib/Sema/SemaDecl.cpp
@@ -16290,8 +16290,10 @@
 
   // Verify that there isn't already something declared with this name in this
   // scope.
-  NamedDecl *PrevDecl = LookupSingleName(S, Id, IdLoc, LookupOrdinaryName,
-                                         ForVisibleRedeclaration);
+  LookupResult R(*this, Id, IdLoc, LookupOrdinaryName, ForVisibleRedeclaration);
+  LookupName(R, S);
+  NamedDecl *PrevDecl = R.getAsSingle<NamedDecl>();
+
   if (PrevDecl && PrevDecl->isTemplateParameter()) {
     // Maybe we will complain about the shadowed template parameter.
     DiagnoseTemplateParameterShadow(IdLoc, PrevDecl);
@@ -16314,6 +16316,9 @@
     return nullptr;
 
   if (PrevDecl) {
+    // Check for other kinds of shadowing not already handled.
+    CheckShadow(New, PrevDecl, R);
+
     // When in C++, we may get a TagDecl with the same name; in this case the
     // enum constant will 'hide' the tag.
     assert((getLangOpts().CPlusPlus || !isa<TagDecl>(PrevDecl)) &&


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