diff mbox

[C++] Fix decomp ICE with invalid initializer (PR c++/81258)

Message ID 20170703160502.GZ2123@tucnak
State New
Headers show

Commit Message

Jakub Jelinek July 3, 2017, 4:05 p.m. UTC 
On Fri, Jun 30, 2017 at 01:38:13PM -0400, Nathan Sidwell wrote:
> On 06/30/2017 01:24 PM, Jakub Jelinek wrote:
> 
> > The initializer for structured binding has to be one of:
> > = assignment-expression
> > ( assignment-expression )
> > { assignment-expression }
> > but cp_parser_initializer can parse other forms, with fewer or more
> > expressions in there.  Some cases we caught with various cryptic errors
> > or pedwarns, but others we just ICEd on.
> > 
> > The following patch attempts to check this.
> 
> ok, but ...
> 
> > --- gcc/testsuite/g++.dg/cpp1z/decomp21.C.jj	2017-01-19 17:01:21.000000000 +0100
> > +++ gcc/testsuite/g++.dg/cpp1z/decomp21.C	2017-06-30 11:07:04.786746784 +0200
> > @@ -12,5 +12,5 @@ foo ()
> >     auto [ n, o, p ] { a };
> >     auto [ q, r, t ] ( s );
> >     auto [ u, v, w ] ( s, );      // { dg-error "expected primary-expression before '.' token" }
> > -  auto [ x, y, z ] ( a );       // { dg-error "expression list treated as compound expression in initializer" "" { target *-*-* } .-1 }
> > +  auto [ x, y, z ] ( a );       // { dg-error "invalid initializer for structured binding" "" { target *-*-* } .-1 }
> >   }
> 
> The .-1 on the final error is actually about the previous statement, not the
> line it's lexically on.  Could you put it on a line on its own, while you're
> there?

Ok.  In the light of the http://gcc.gnu.org/ml/gcc-patches/2017-06/msg02432.html
thread, shouldn't this be structured binding declaration then?
I.e.

2017-07-03  Jakub Jelinek  <jakub@redhat.com>

	PR c++/81258
	* parser.c (cp_parser_decomposition_declaration): Diagnose invalid
	forms of structured binding initializers.

	* g++.dg/cpp1z/decomp21.C (foo): Adjust expected diagnostics.
	* g++.dg/cpp1z/decomp30.C: New test.



	Jakub

Comments

Nathan Sidwell July 3, 2017, 4:48 p.m. UTC | #1 
On 07/03/2017 12:05 PM, Jakub Jelinek wrote:

> Ok.  In the light of the http://gcc.gnu.org/ml/gcc-patches/2017-06/msg02432.html
> thread, shouldn't this be structured binding declaration then?
> I.e.

Yes, I think that's better, thanks!

nathan
diff mbox

Patch

--- gcc/cp/parser.c.jj	2017-06-30 09:49:25.000000000 +0200
+++ gcc/cp/parser.c	2017-06-30 11:03:18.526521000 +0200
@@ -13196,6 +13196,16 @@  cp_parser_decomposition_declaration (cp_
       *init_loc = cp_lexer_peek_token (parser->lexer)->location;
       tree initializer = cp_parser_initializer (parser, &is_direct_init,
 						&non_constant_p);
+      if (initializer == NULL_TREE
+	  || (TREE_CODE (initializer) == TREE_LIST
+	      && TREE_CHAIN (initializer))
+	  || (TREE_CODE (initializer) == CONSTRUCTOR
+	      && CONSTRUCTOR_NELTS (initializer) != 1))
+	{
+	  error_at (loc, "invalid initializer for structured binding "
+		    "declaration");
+	  initializer = error_mark_node;
+	}
 
       if (decl != error_mark_node)
 	{
--- gcc/testsuite/g++.dg/cpp1z/decomp21.C.jj	2017-01-19 17:01:21.000000000 +0100
+++ gcc/testsuite/g++.dg/cpp1z/decomp21.C	2017-06-30 11:07:04.786746784 +0200
@@ -12,5 +12,6 @@  foo ()
   auto [ n, o, p ] { a };
   auto [ q, r, t ] ( s );
   auto [ u, v, w ] ( s, );      // { dg-error "expected primary-expression before '.' token" }
-  auto [ x, y, z ] ( a );       // { dg-error "expression list treated as compound expression in initializer" "" { target *-*-* } .-1 }
+				// { dg-error "invalid initializer for structured binding declaration" "" { target *-*-* } .-1 }
+  auto [ x, y, z ] ( a );
 }
--- gcc/testsuite/g++.dg/cpp1z/decomp30.C.jj	2017-06-30 11:09:31.934942575 +0200
+++ gcc/testsuite/g++.dg/cpp1z/decomp30.C	2017-06-30 11:09:22.000000000 +0200
@@ -0,0 +1,12 @@ 
+// PR c++/81258
+// { dg-options -std=c++1z }
+
+int a[2];
+auto [b, c] (a);
+auto [d, e] { a };
+auto [f, g] = a;
+auto [h, i] ( a, a );	// { dg-error "invalid initializer for structured binding declaration" }
+auto [j, k] { a, a };	// { dg-error "invalid initializer for structured binding declaration" }
+auto [l, m] = { a };	// { dg-error "deducing from brace-enclosed initializer list requires" }
+auto [n, o] {};		// { dg-error "invalid initializer for structured binding declaration" }
+auto [p, q] ();		// { dg-error "invalid initializer for structured binding declaration" }