Sema: handle AttributedTypeLocs in C++14 auto deduction

When performing a type deduction from the return type, the FunctionDecl may be
attributed with a calling convention.  In such a case, the retrieved type
location may be an AttributedTypeLoc.  Performing a castAs<FunctionProtoTypeLoc>
on such a type loc would result in an assertion as they are not derived types.

Ensure that we correctly handle the attributed type location by looking through
it to the modified type loc.

Fixes an assertion triggered in C++14 mode.

llvm-svn: 219851

2 files changed, 15 insertions, 2 deletions

diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index 464206eafe3..c03ac86de05 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -2755,8 +2755,11 @@ bool Sema::DeduceFunctionTypeFromReturnExpr(FunctionDecl *FD,
                                             SourceLocation ReturnLoc,
                                             Expr *&RetExpr,
                                             AutoType *AT) {
-  TypeLoc OrigResultType = FD->getTypeSourceInfo()->getTypeLoc().
-    IgnoreParens().castAs<FunctionProtoTypeLoc>().getReturnLoc();
+  TypeLoc TL = FD->getTypeSourceInfo()->getTypeLoc();
+  if (auto ATL = TL.getAs<AttributedTypeLoc>())
+    TL = ATL.getModifiedLoc();
+  TypeLoc OrigResultType =
+      TL.IgnoreParens().castAs<FunctionProtoTypeLoc>().getReturnLoc();
   QualType Deduced;
 
   if (RetExpr && isa<InitListExpr>(RetExpr)) {
diff --git a/clang/test/Sema/attributed-auto-deduction.cpp b/clang/test/Sema/attributed-auto-deduction.cpp
new file mode 100644
index 00000000000..d8dc43d6691
--- /dev/null
+++ b/clang/test/Sema/attributed-auto-deduction.cpp
@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 -triple armv7 -std=c++14 -x c++ %s -fsyntax-only
+// expected-no-diagnostics
+
+void deduce() {
+  auto lambda = [](int i) __attribute__ (( pcs("aapcs") )) {
+    return i;
+  };
+  lambda(42);
+}
+