[PATCH] D45411: [Sema] Fix PR35832 - Ambiguity accessing anonymous struct/union with multiple bases.

[Eric Fiselier via Phabricator via cfe-commits]

EricWF created this revision.
EricWF added reviewers: rsmith, aaron.ballman, rjmccall.
EricWF added a dependency: D45410: [Sema] Remove dead code in 
BuildAnonymousStructUnionMemberReference. NFCI.

Currently clang doesn't do qualified lookup when building indirect field decl 
references. This causes ambiguity when the field is in a base class to which 
there are multiple valid paths  even though a qualified name is used.

For example:

  class B {
  protected:
   int i;
   union { int j; };
  };
  
  class X : public B { };
  class Y : public B { };
  
  class Z : public X, public Y {
   int a() { return X::i; } // works
   int b() { return X::j; } // fails
  };


Repository:
  rC Clang

https://reviews.llvm.org/D45411

Files:
  lib/Sema/SemaExprMember.cpp
  test/SemaCXX/PR35832.cpp


Index: test/SemaCXX/PR35832.cpp
===================================================================
--- /dev/null
+++ test/SemaCXX/PR35832.cpp
@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+// expected-no-diagnostics
+
+class B {
+public:
+ int i;
+ struct {  struct { union { int j; }; };  };
+};
+
+auto ptr = &B::j;
+
+class X : public B { };
+class Y : public B { static B bb; };
+
+class Z : public X {
+public:
+ int a() { return X::i; }
+ int b() { return X::j; }
+ int c() { return this->X::j; }
+};
Index: lib/Sema/SemaExprMember.cpp
===================================================================
--- lib/Sema/SemaExprMember.cpp
+++ lib/Sema/SemaExprMember.cpp
@@ -848,7 +848,7 @@
     // Build the first member access in the chain with full information.
     result =
         BuildFieldReferenceExpr(result, baseObjectIsPointer, SourceLocation(),
-                                EmptySS, field, foundDecl, memberNameInfo)
+                                SS, field, foundDecl, memberNameInfo)
             .get();
     if (!result)
       return ExprError();



Index: test/SemaCXX/PR35832.cpp
===================================================================
--- /dev/null
+++ test/SemaCXX/PR35832.cpp
@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+// expected-no-diagnostics
+
+class B {
+public:
+ int i;
+ struct {  struct { union { int j; }; };  };
+};
+
+auto ptr = &B::j;
+
+class X : public B { };
+class Y : public B { static B bb; };
+
+class Z : public X {
+public:
+ int a() { return X::i; }
+ int b() { return X::j; }
+ int c() { return this->X::j; }
+};
Index: lib/Sema/SemaExprMember.cpp
===================================================================
--- lib/Sema/SemaExprMember.cpp
+++ lib/Sema/SemaExprMember.cpp
@@ -848,7 +848,7 @@
     // Build the first member access in the chain with full information.
     result =
         BuildFieldReferenceExpr(result, baseObjectIsPointer, SourceLocation(),
-                                EmptySS, field, foundDecl, memberNameInfo)
+                                SS, field, foundDecl, memberNameInfo)
             .get();
     if (!result)
       return ExprError();

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