[c++20] Fix some ambiguities in our mangling of lambdas with explicit

template parameters.

This finishes the implementation of the proposal described in
https://github.com/itanium-cxx-abi/cxx-abi/issues/31. (We already
implemented the <lambda-sig> extensions, but didn't take them into
account when computing mangling numbers, and didn't deal properly with
expanded parameter packs, and didn't disambiguate between different
levels of template parameters in manglings.)

llvm-svn: 371004

1 files changed, 7 insertions, 0 deletions

diff --git a/clang/lib/AST/DeclBase.cpp b/clang/lib/AST/DeclBase.cpp
index fd80e15..aa2c212 100644
--- a/clang/lib/AST/DeclBase.cpp
+++ b/clang/lib/AST/DeclBase.cpp
@@ -12,6 +12,7 @@
 
 #include "clang/AST/DeclBase.h"
 #include "clang/AST/ASTContext.h"
+#include "clang/AST/ASTLambda.h"
 #include "clang/AST/ASTMutationListener.h"
 #include "clang/AST/Attr.h"
 #include "clang/AST/AttrIterator.h"
@@ -1043,6 +1044,12 @@ DeclContext *DeclContext::getLookupParent() {
         getLexicalParent()->getRedeclContext()->isRecord())
       return getLexicalParent();
 
+  // A lookup within the call operator of a lambda never looks in the lambda
+  // class; instead, skip to the context in which that closure type is
+  // declared.
+  if (isLambdaCallOperator(this))
+    return getParent()->getParent();
+
   return getParent();
 }