PR22117: Fix a case where we would get confused about which function parameter

we're instantiating, if there's a ParmVarDecl within a FunctionDecl context
that is not a parameter of that function. Add some asserts to catch this kind
of issue more generally, and fix another bug exposed by those asserts where we
were missing a local instantiation scope around substitution of
explicitly-specified template arguments.

llvm-svn: 225490

1 files changed, 10 insertions, 1 deletions

diff --git a/clang/test/SemaCXX/cxx1y-generic-lambdas.cpp b/clang/test/SemaCXX/cxx1y-generic-lambdas.cpp
index 395b5803236..90ecf6904e5 100644
--- a/clang/test/SemaCXX/cxx1y-generic-lambdas.cpp
+++ b/clang/test/SemaCXX/cxx1y-generic-lambdas.cpp
@@ -921,4 +921,13 @@ int run2 = x2.fooG3();
 
 namespace pr21684_disambiguate_auto_followed_by_ellipsis_no_id {
 int a = [](auto ...) { return 0; }();
-}
\ No newline at end of file
+}
+
+namespace PR22117 {
+  int x = [](auto) {
+    return [](auto... run_args) {
+      using T = int(decltype(run_args)...);
+      return 0;
+    };
+  }(0)(0);
+}