re PR c++/79654 (ICE on invalid c++ code in register_dtor_fn in cp/decl.c:7877)

	PR c++/79654
	* decl.c (cp_finish_decomp): Don't set decl's type to error_mark_node
	on error.
	* pt.c (tsubst_decomp_names): Return error_mark_node if the first
	decl after the decomposition artificial decl has error_mark_node.
	* decl2.c (prune_vars_needing_no_initialization): Use error_operand_p
	instead of just == error_mark_node comparison.

	* g++.dg/cpp1z/decomp26.C: New test.

Co-Authored-By: Paolo Carlini <paolo.carlini@oracle.com>

From-SVN: r245639

gcc/cp/ChangeLog

 2017-02-21  Jakub Jelinek  <jakub@redhat.com>
+	    Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/79654
+	* decl.c (cp_finish_decomp): Don't set decl's type to error_mark_node
+	on error.
+	* pt.c (tsubst_decomp_names): Return error_mark_node if the first
+	decl after the decomposition artificial decl has error_mark_node.
+	* decl2.c (prune_vars_needing_no_initialization): Use error_operand_p
+	instead of just == error_mark_node comparison.
+
+2017-02-21  Jakub Jelinek  <jakub@redhat.com>
 
 	PR sanitizer/79589
 	* decl.c: Include gimplify.h.

gcc/cp/decl.c

@@ -7386,7 +7386,6 @@ cp_finish_decomp (tree decl, tree first, unsigned int count)
 	    }
 	  first = DECL_CHAIN (first);
 	}
-      TREE_TYPE (decl) = error_mark_node;
       if (DECL_P (decl) && DECL_NAMESPACE_SCOPE_P (decl))
 	SET_DECL_ASSEMBLER_NAME (decl, get_identifier ("<decomp>"));
       return;

gcc/cp/decl2.c

@@ -3879,7 +3879,7 @@ prune_vars_needing_no_initialization (tree *vars)
       tree init = TREE_PURPOSE (t);
 
       /* Deal gracefully with error.  */
-      if (decl == error_mark_node)
+      if (error_operand_p (decl))
 	{
 	  var = &TREE_CHAIN (t);
 	  continue;

gcc/cp/pt.c

@@ -15610,6 +15610,11 @@ tsubst_decomp_names (tree decl, tree pattern_decl, tree args,
        && DECL_NAME (decl2);
        decl2 = DECL_CHAIN (decl2))
     {
+      if (TREE_TYPE (decl2) == error_mark_node && *cnt == 0)
+	{
+	  gcc_assert (errorcount);
+	  return error_mark_node;
+	}
       (*cnt)++;
       gcc_assert (DECL_HAS_VALUE_EXPR_P (decl2));
       tree v = DECL_VALUE_EXPR (decl2);

gcc/testsuite/ChangeLog

 2017-02-21  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c++/79654
+	* g++.dg/cpp1z/decomp26.C: New test.
+
 	PR sanitizer/79589
 	* g++.dg/ubsan/pr79589.C: New test.
 

gcc/testsuite/g++.dg/cpp1z/decomp26.C

+// PR c++/79654
+// { dg-do compile { target c++11 } }
+// { dg-options "" }
+
+template<typename T> T &make();	// { dg-warning "decomposition declaration only available with" "" { target c++14_down } .+1 }
+auto [d1, d2] = make<int>();	// { dg-error "cannot decompose non-array non-class type" }