[C++ PATCH] Fix C++ ICE due to CONVERT_EXPR of error_mark_node (PR c++/84662)

[C++ PATCH] Fix C++ ICE due to CONVERT_EXPR of error_mark_node (PR c++/84662)

[Jakub Jelinek]

Hi!

Various spots in the FE don't really like if error_mark_node is deeply
embedded in expression operands, in this case tsubst_copy_and_build
creates CONVERT_EXPR <some_type, error_mark_node> on which
is_bitfield_expr_with_lowered_type ICEs.

Fixed by just returning error_mark_node (various other spots in
tsubst_copy_and_build do the same).

While at it, I've discovered 3 spots in the function which were using
return instead of RETURN and thus wouldn't properly restore input_location;
I wonder if eventually this shouldn't be done through some sentinel class
where the destructor would restore input_location and just use return
instead of RETURN.

Anyway, bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2018-03-02  <jakub@redhat.com>

	PR c++/84662
	* pt.c (tsubst_copy_and_build) <case TEMPLATE_ID_EXPR>: Use
	RETURN instead of return.
	<case POINTER_PLUS_EXPR>: Likewise.
	<case CONVERT_EXPR>: If op0 is error_mark_node, just return
	it instead of wrapping it into CONVERT_EXPR.

	* g++.dg/cpp1y/pr84662.C: New test.

--- gcc/cp/pt.c.jj	2018-03-02 00:15:54.097781049 +0100
+++ gcc/cp/pt.c	2018-03-02 12:30:38.127232430 +0100
@@ -17318,14 +17318,14 @@ tsubst_copy_and_build (tree t,
 	if (targs)
 	  targs = tsubst_template_args (targs, args, complain, in_decl);
 	if (targs == error_mark_node)
-	  return error_mark_node;
+	  RETURN (error_mark_node);
 
 	if (TREE_CODE (templ) == SCOPE_REF)
 	  {
 	    tree name = TREE_OPERAND (templ, 1);
 	    tree tid = lookup_template_function (name, targs);
 	    TREE_OPERAND (templ, 1) = tid;
-	    return templ;
+	    RETURN (templ);
 	  }
 
 	if (variable_template_p (templ))
@@ -17401,6 +17401,8 @@ tsubst_copy_and_build (tree t,
       {
 	tree type = tsubst (TREE_TYPE (t), args, complain, in_decl);
 	tree op0 = RECUR (TREE_OPERAND (t, 0));
+	if (op0 == error_mark_node)
+	  RETURN (error_mark_node);
 	RETURN (build1 (CONVERT_EXPR, type, op0));
       }
 
@@ -17549,7 +17551,7 @@ tsubst_copy_and_build (tree t,
       {
 	tree op0 = RECUR (TREE_OPERAND (t, 0));
 	tree op1 = RECUR (TREE_OPERAND (t, 1));
-	return fold_build_pointer_plus (op0, op1);
+	RETURN (fold_build_pointer_plus (op0, op1));
       }
 
     case SCOPE_REF:
--- gcc/testsuite/g++.dg/cpp1y/pr84662.C.jj	2018-03-02 12:32:23.012209212 +0100
+++ gcc/testsuite/g++.dg/cpp1y/pr84662.C	2018-03-02 12:32:59.159201202 +0100
@@ -0,0 +1,6 @@
+// PR c++/84662
+// { dg-do compile { target c++14 } }
+// { dg-options "" }
+
+double b;
+a (__attribute__((c (0 && int() - ([] {} && b) || auto))));	// { dg-error "expected constructor, destructor, or type conversion before" }

	Jakub

Re: [C++ PATCH] Fix C++ ICE due to CONVERT_EXPR of error_mark_node (PR c++/84662)

[Nathan Sidwell]

On 03/02/2018 11:25 AM, Jakub Jelinek wrote:
> Hi!
> 
> Various spots in the FE don't really like if error_mark_node is deeply
> embedded in expression operands, in this case tsubst_copy_and_build
> creates CONVERT_EXPR <some_type, error_mark_node> on which
> is_bitfield_expr_with_lowered_type ICEs.
> 
> Fixed by just returning error_mark_node (various other spots in
> tsubst_copy_and_build do the same).
> 
> While at it, I've discovered 3 spots in the function which were using
> return instead of RETURN and thus wouldn't properly restore input_location;
> I wonder if eventually this shouldn't be done through some sentinel class
> where the destructor would restore input_location and just use return
> instead of RETURN.
> 
> Anyway, bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

ok, thanks

nathan


-- 
Nathan Sidwell