Replace the workaround from r153445 with a proper fix.

Infinite recursion was happening when DiagnoseInvalidRedeclaration
called ActOnFunctionDeclarator to check if a typo correction works when
the correction was just to the nested-name-specifier because the wrong
DeclContext was being passed in. Unlike a number of functions
surrounding typo correction, the DeclContext passed in for a function is
the context of the function name after applying any nested name
specifiers, not the lexical DeclContext where the
function+nested-name-specifier appears.

llvm-svn: 153962

clang/include/clang/Sema/TypoCorrection.h

@@ -205,7 +205,7 @@ class CorrectionCandidateCallback {
       : WantTypeSpecifiers(true), WantExpressionKeywords(true),
         WantCXXNamedCasts(true), WantRemainingKeywords(true),
         WantObjCSuper(false),
-        IsObjCIvarLookup(false), AllowAddedQualifier(true) {}
+        IsObjCIvarLookup(false) {}
 
   virtual ~CorrectionCandidateCallback() {}
 
@@ -239,10 +239,6 @@ class CorrectionCandidateCallback {
   // Temporary hack for the one case where a CorrectTypoContext enum is used
   // when looking up results.
   bool IsObjCIvarLookup;
-  
-  /// \brief Whether to allow this typo correction to add a 
-  /// nested-name-specifier.
-  bool AllowAddedQualifier;
 };
 
 /// @brief Simple template class for restricting typo correction candidates

clang/lib/Sema/SemaDecl.cpp

@@ -4500,14 +4500,7 @@ namespace {
 class DifferentNameValidatorCCC : public CorrectionCandidateCallback {
  public:
   DifferentNameValidatorCCC(CXXRecordDecl *Parent)
-      : ExpectedParent(Parent ? Parent->getCanonicalDecl() : 0) {
-    // Don't allow any additional qualification.
-    // FIXME: It would be nice to perform this additional qualification. 
-    // However, DiagnoseInvalidRedeclaration is unable to handle the 
-    // qualification, because it doesn't know how to pass the corrected
-    // nested-name-specifier through to ActOnFunctionDeclarator.
-    AllowAddedQualifier = false;
-  }
+      : ExpectedParent(Parent ? Parent->getCanonicalDecl() : 0) {}
 
   virtual bool ValidateCandidate(const TypoCorrection &candidate) {
     if (candidate.getEditDistance() == 0)
@@ -4596,12 +4589,11 @@ static NamedDecl* DiagnoseInvalidRedeclaration(
     // TODO: Refactor ActOnFunctionDeclarator so that we can call only the
     // pieces need to verify the typo-corrected C++ declaraction and hopefully
     // eliminate the need for the parameter pack ExtraArgs.
-    Result = SemaRef.ActOnFunctionDeclarator(ExtraArgs.S, ExtraArgs.D,
-                                             NewFD->getDeclContext(),
-                                             NewFD->getTypeSourceInfo(),
-                                             Previous,
-                                             ExtraArgs.TemplateParamLists,
-                                             ExtraArgs.AddToScope);
+    Result = SemaRef.ActOnFunctionDeclarator(
+        ExtraArgs.S, ExtraArgs.D,
+        Correction.getCorrectionDecl()->getDeclContext(),
+        NewFD->getTypeSourceInfo(), Previous, ExtraArgs.TemplateParamLists,
+        ExtraArgs.AddToScope);
     if (Trap.hasErrorOccurred()) {
       // Pretend the typo correction never occurred
       ExtraArgs.D.SetIdentifier(Name.getAsIdentifierInfo(),

clang/lib/Sema/SemaLookup.cpp

@@ -3815,7 +3815,7 @@ TypoCorrection Sema::CorrectTypo(const DeclarationNameInfo &TypoName,
   // Determine whether we are going to search in the various namespaces for
   // corrections.
   bool SearchNamespaces
-    = getLangOpts().CPlusPlus && CCC.AllowAddedQualifier && 
+    = getLangOpts().CPlusPlus &&
       (IsUnqualifiedLookup || (QualifiedDC && QualifiedDC->isNamespace()));
   
   if (IsUnqualifiedLookup || SearchNamespaces) {

clang/test/FixIt/typo-crash.cpp

@@ -19,11 +19,11 @@ namespace PR12297 {
     namespace B {
       typedef short   T;
         
-      T global();
+      T global(); // expected-note {{'A::B::global' declared here}}
     }
   }
 
   using namespace A::B;
 
-  T A::global(); // expected-error{{out-of-line definition of 'global' does not match any declaration in namespace 'PR12297::A'}}
+  T A::global(); // expected-error {{out-of-line definition of 'global' does not match any declaration in namespace 'PR12297::A'; did you mean 'A::B::global'?}}
 }