From 0179868cce096101236261ff64eca30224b1f233 Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Mon, 26 Mar 2012 16:54:18 +0000
Subject: [PATCH] When diagnosing an invalid out-of-line redeclaration, don't
 permit typo correction to introduce a nested-name-specifier; we aren't
 prepared to handle it here. Fixes PR12297 / <rdar://problem/11075219>.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@153445 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/clang/Sema/TypoCorrection.h |  6 +++++-
 lib/Sema/SemaDecl.cpp               |  9 ++++++++-
 lib/Sema/SemaLookup.cpp             | 15 +++++++++++----
 test/FixIt/typo-crash.cpp           | 17 +++++++++++++++++
 4 files changed, 41 insertions(+), 6 deletions(-)

diff --git a/include/clang/Sema/TypoCorrection.h b/include/clang/Sema/TypoCorrection.h
index a8f6e1178b..a333c8182b 100644
--- a/include/clang/Sema/TypoCorrection.h
+++ b/include/clang/Sema/TypoCorrection.h
@@ -205,7 +205,7 @@ class CorrectionCandidateCallback {
       : WantTypeSpecifiers(true), WantExpressionKeywords(true),
         WantCXXNamedCasts(true), WantRemainingKeywords(true),
         WantObjCSuper(false),
-        IsObjCIvarLookup(false) {}
+        IsObjCIvarLookup(false), AllowAddedQualifier(true) {}
 
   virtual ~CorrectionCandidateCallback() {}
 
@@ -239,6 +239,10 @@ 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
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index e92b3e4aca..d4159bf189 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -4478,7 +4478,14 @@ namespace {
 class DifferentNameValidatorCCC : public CorrectionCandidateCallback {
  public:
   DifferentNameValidatorCCC(CXXRecordDecl *Parent)
-      : ExpectedParent(Parent ? Parent->getCanonicalDecl() : 0) {}
+      : 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;
+  }
 
   virtual bool ValidateCandidate(const TypoCorrection &candidate) {
     if (candidate.getEditDistance() == 0)
diff --git a/lib/Sema/SemaLookup.cpp b/lib/Sema/SemaLookup.cpp
index e47bc1c8b1..ed5a8da61c 100644
--- a/lib/Sema/SemaLookup.cpp
+++ b/lib/Sema/SemaLookup.cpp
@@ -3806,7 +3806,13 @@ TypoCorrection Sema::CorrectTypo(const DeclarationNameInfo &TypoName,
     }
   }
 
-  if (IsUnqualifiedLookup || (QualifiedDC && QualifiedDC->isNamespace())) {
+  // Determine whether we are going to search in the various namespaces for
+  // corrections.
+  bool SearchNamespaces
+    = getLangOpts().CPlusPlus && CCC.AllowAddedQualifier && 
+      (IsUnqualifiedLookup || (QualifiedDC && QualifiedDC->isNamespace()));
+  
+  if (IsUnqualifiedLookup || SearchNamespaces) {
     // For unqualified lookup, look through all of the names that we have
     // seen in this translation unit.
     // FIXME: Re-add the ability to skip very unlikely potential corrections.
@@ -3852,8 +3858,9 @@ TypoCorrection Sema::CorrectTypo(const DeclarationNameInfo &TypoName,
     return TypoCorrection();
   }
 
-  // Build the NestedNameSpecifiers for the KnownNamespaces
-  if (getLangOpts().CPlusPlus) {
+  // Build the NestedNameSpecifiers for the KnownNamespaces, if we're going
+  // to search those namespaces.
+  if (SearchNamespaces) {
     // Load any externally-known namespaces.
     if (ExternalSource && !LoadedExternalKnownNamespaces) {
       SmallVector<NamespaceDecl *, 4> ExternalKnownNamespaces;
@@ -3948,7 +3955,7 @@ TypoCorrection Sema::CorrectTypo(const DeclarationNameInfo &TypoName,
       break;
 
     // Only perform the qualified lookups for C++
-    if (getLangOpts().CPlusPlus) {
+    if (SearchNamespaces) {
       TmpRes.suppressDiagnostics();
       for (llvm::SmallVector<TypoCorrection,
                              16>::iterator QRI = QualifiedResults.begin(),
diff --git a/test/FixIt/typo-crash.cpp b/test/FixIt/typo-crash.cpp
index 92d20377e8..2e6f34a2a0 100644
--- a/test/FixIt/typo-crash.cpp
+++ b/test/FixIt/typo-crash.cpp
@@ -10,3 +10,20 @@ template<typename T> void template_id1() { // expected-note {{'template_id1' dec
   // expected-error {{reference to overloaded function could not be resolved; did you mean to call it?}} \
   // expected-error {{use of undeclared identifier 't'}}
  }
+
+// FIXME: It would be nice if we could get this correction right.
+namespace PR12297 {
+  namespace A {
+    typedef short   T;
+    
+    namespace B {
+      typedef short   T;
+        
+      T global();
+    }
+  }
+
+  using namespace A::B;
+
+  T A::global(); // expected-error{{out-of-line definition of 'global' does not match any declaration in namespace 'PR12297::A'}}
+}
-- 
2.40.0