Improve the diagnostic when trying to redefine a typedef with a

variably-modified type.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@147973 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 15 insertions, 2 deletions

diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index 74189ca947..4341dbbfa9 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2754,6 +2754,8 @@ def note_used_here : Note<"used here">;
 def warn_redefinition_of_typedef : ExtWarn<
   "redefinition of typedef %0 is a C11 feature">,
   InGroup<DiagGroup<"typedef-redefinition"> >;
+def err_redefinition_variably_modified_typedef : Error<
+  "redefinition of %select{typedef|type alias}0 for variably-modified type %1">;
 
 def err_inline_declaration_block_scope : Error<
   "inline declaration of %0 not allowed in block scope">;
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 588fc14044..f30f1fa5be 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -1383,10 +1383,21 @@ bool Sema::isIncompatibleTypedef(TypeDecl *Old, TypedefNameDecl *New) {
     OldType = Context.getTypeDeclType(Old);
   QualType NewType = New->getUnderlyingType();
 
+  if (NewType->isVariablyModifiedType()) {
+    // Must not redefine a typedef with a variably-modified type.
+    int Kind = isa<TypeAliasDecl>(Old) ? 1 : 0;
+    Diag(New->getLocation(), diag::err_redefinition_variably_modified_typedef)
+      << Kind << NewType;
+    if (Old->getLocation().isValid())
+      Diag(Old->getLocation(), diag::note_previous_definition);
+    New->setInvalidDecl();
+    return true;    
+  }
+  
   if (OldType != NewType &&
       !OldType->isDependentType() &&
       !NewType->isDependentType() &&
-      !Context.hasSameType(OldType, NewType)) {
+      !Context.hasSameType(OldType, NewType)) { 
     int Kind = isa<TypeAliasDecl>(Old) ? 1 : 0;
     Diag(New->getLocation(), diag::err_redefinition_different_typedef)
       << Kind << NewType << OldType;
diff --git a/test/Sema/c11-typedef-redef.c b/test/Sema/c11-typedef-redef.c
index 7e213f49cf..a6720a171b 100644
--- a/test/Sema/c11-typedef-redef.c
+++ b/test/Sema/c11-typedef-redef.c
@@ -10,5 +10,5 @@ void f(int N) {
   typedef int type2;
 
   typedef int vla[N]; // expected-note{{previous definition is here}}
-  typedef int vla[N]; // expected-error{{typedef redefinition with different types ('int [N]' vs 'int [N]')}}
+  typedef int vla[N]; // expected-error{{redefinition of typedef for variably-modified type 'int [N]'}}
 }