Sema: Don't permit variably modified types in typeid

GCC and ICC both reject this and the 'Runtime-sized arrays with
automatic storage duration' (N3639) paper forbade this as well.
Previously, we would crash on our way to mangling.

This fixes PR21632.

llvm-svn: 222569

1 files changed, 7 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index 93996685105..c71a4e93bbd 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -384,6 +384,9 @@ ExprResult Sema::BuildCXXTypeId(QualType TypeInfoType,
       RequireCompleteType(TypeidLoc, T, diag::err_incomplete_typeid))
     return ExprError();
 
+  if (T->isVariablyModifiedType())
+    return ExprError(Diag(TypeidLoc, diag::err_variably_modified_typeid) << T);
+
   return new (Context) CXXTypeidExpr(TypeInfoType.withConst(), Operand,
                                      SourceRange(TypeidLoc, RParenLoc));
 }
@@ -438,6 +441,10 @@ ExprResult Sema::BuildCXXTypeId(QualType TypeInfoType,
     }
   }
 
+  if (E->getType()->isVariablyModifiedType())
+    return ExprError(Diag(TypeidLoc, diag::err_variably_modified_typeid)
+                     << E->getType());
+
   return new (Context) CXXTypeidExpr(TypeInfoType.withConst(), E,
                                      SourceRange(TypeidLoc, RParenLoc));
 }