Fix for PR30632: Name mangling issue.

There was a bug in the implementation of captured statements. If it has
a lambda expression in it and the same lambda expression is used outside
the captured region, clang produced an error:
```
error: definition with same mangled name as another definition
```
Here is an example:
```
struct A {
 template <typename L>
 void g(const L&) { }
};

template<typename T>
void f() {
  {
    A().g([](){});
  }
  A().g([](){});
}

int main() {
  f<void>();
}
```

Error report:
```
main.cpp:3:10: error: definition with same mangled name as another
definition
    void g(const L&) { }
             ^
main.cpp:3:10: note: previous definition is here
```
Patch fixes this bug.

llvm-svn: 284229

1 files changed, 5 insertions, 3 deletions

diff --git a/clang/lib/Sema/SemaLambda.cpp b/clang/lib/Sema/SemaLambda.cpp
index 0de501fc5e4..9be8fe51887 100644
--- a/clang/lib/Sema/SemaLambda.cpp
+++ b/clang/lib/Sema/SemaLambda.cpp
@@ -311,18 +311,20 @@ Sema::getCurrentMangleNumberContext(const DeclContext *DC,
   bool IsInNonspecializedTemplate =
     !ActiveTemplateInstantiations.empty() || CurContext->isDependentContext();
   switch (Kind) {
-  case Normal:
+  case Normal: {
     //  -- the bodies of non-exported nonspecialized template functions
     //  -- the bodies of inline functions
+    auto *CD = dyn_cast<CapturedDecl>(CurContext);
     if ((IsInNonspecializedTemplate &&
          !(ManglingContextDecl && isa<ParmVarDecl>(ManglingContextDecl))) ||
-        isInInlineFunction(CurContext)) {
+        isInInlineFunction(CurContext) || CD) {
       ManglingContextDecl = nullptr;
-      return &Context.getManglingNumberContext(DC);
+      return &Context.getManglingNumberContext(CD ? CD->getParent() : DC);
     }
 
     ManglingContextDecl = nullptr;
     return nullptr;
+  }
 
   case StaticDataMember:
     //  -- the initializers of nonspecialized static members of template classes