Merging r197409:
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r197409 | rikka | 2013-12-16 11:19:18 -0800 (Mon, 16 Dec 2013) | 4 lines

Make Sema::BuildCXXNestedNameSpecifier correctly clear the previous
CXXScopeSpec when necessary while performing typo correction. This fixes
the crash reported in PR18213 (the problem existed since r185487, and
r193020 made it easier to hit).
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git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_34@197463 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaCXXScopeSpec.cpp b/lib/Sema/SemaCXXScopeSpec.cpp
index 674411e..554a114 100644
--- a/lib/Sema/SemaCXXScopeSpec.cpp
+++ b/lib/Sema/SemaCXXScopeSpec.cpp
@@ -497,6 +497,8 @@
         bool DroppedSpecifier =
             Corrected.WillReplaceSpecifier() &&
             Name.getAsString() == Corrected.getAsString(getLangOpts());
+        if (DroppedSpecifier)
+          SS.clear();
         diagnoseTypo(Corrected, PDiag(diag::err_no_member_suggest)
                                   << Name << LookupCtx << DroppedSpecifier
                                   << SS.getRange());
diff --git a/test/SemaCXX/typo-correction-pt2.cpp b/test/SemaCXX/typo-correction-pt2.cpp
index 2da52b3..525d11b 100644
--- a/test/SemaCXX/typo-correction-pt2.cpp
+++ b/test/SemaCXX/typo-correction-pt2.cpp
@@ -181,3 +181,21 @@
   MessageHeaders::ParseMessageHeaders(5, 4); // expected-error {{no member named 'ParseMessageHeaders' in 'fix_class_name_qualifier::MessageHeaders'; did you mean 'MessageUtils::ParseMessageHeaders'?}}
 }
 }
+
+namespace PR18213 {  // expected-note {{'PR18213' declared here}}
+struct WrapperInfo {
+  int i;
+};
+
+template <typename T> struct Wrappable {
+  static WrapperInfo kWrapperInfo;
+};
+
+// Note the space before "::PR18213" is intended and needed, as it highlights
+// the actual typo, which is the leading "::".
+// TODO: Suggest removing the "::" from "::PR18213" (the right correction)
+// instead of incorrectly suggesting dropping "PR18213::WrapperInfo::".
+template <>
+PR18213::WrapperInfo ::PR18213::Wrappable<int>::kWrapperInfo = { 0 };  // expected-error {{no member named 'PR18213' in 'PR18213::WrapperInfo'; did you mean simply 'PR18213'?}} \
+                                                                       // expected-error {{C++ requires a type specifier for all declarations}}
+}