C++ PATCH for c++/42315 (ICE after error with invalid array init)

[Jason Merrill]

In this bug, when we see the invalid initializer we changed the type of 
x to be error_mark_node.  But we had already built an ARRAY_REF to it 
using the incomplete type.  Then the back end gets confused by this 
invalid expression wrapped in a valid one.

Fixed by not messing with the type of x.
Tested x86_64-pc-linux-gnu, applying to trunk.
commit 1c880bb1328d3815435cf0695e180ab7fe1c47ec
Author: Jason Merrill <ja...@redhat.com>
Date:   Fri Dec 14 11:36:43 2012 -0500

    	PR c++/42315
    	* decl.c (maybe_deduce_size_from_array_init): Don't change the
    	variable type.

diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index cdda2f4..64bd4b5 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -4834,14 +4834,12 @@ maybe_deduce_size_from_array_init (tree decl, tree init)
 	  if (failure == 1)
 	    {
 	      error ("initializer fails to determine size of %qD", decl);
-	      TREE_TYPE (decl) = error_mark_node;
 	    }
 	  else if (failure == 2)
 	    {
 	      if (do_default)
 		{
 		  error ("array size missing in %qD", decl);
-		  TREE_TYPE (decl) = error_mark_node;
 		}
 	      /* If a `static' var's size isn't known, make it extern as
 		 well as static, so it does not get allocated.  If it's not
@@ -4853,7 +4851,6 @@ maybe_deduce_size_from_array_init (tree decl, tree init)
 	  else if (failure == 3)
 	    {
 	      error ("zero-size array %qD", decl);
-	      TREE_TYPE (decl) = error_mark_node;
 	    }
 	}
 
diff --git a/gcc/testsuite/g++.dg/gomp/pr34964.C b/gcc/testsuite/g++.dg/gomp/pr34964.C
index f5995a6..a02faa2 100644
--- a/gcc/testsuite/g++.dg/gomp/pr34964.C
+++ b/gcc/testsuite/g++.dg/gomp/pr34964.C
@@ -2,5 +2,5 @@
 // { dg-do compile }
 // { dg-options "-fopenmp" }
 
-char x[] = 0;	// { dg-error "initializer fails to determine size" }
+char x[] = 0;	// { dg-error "initializer" }
 #pragma omp threadprivate (x)
diff --git a/gcc/testsuite/g++.dg/init/array21.C b/gcc/testsuite/g++.dg/init/array21.C
index f41ce86..5438af1 100644
--- a/gcc/testsuite/g++.dg/init/array21.C
+++ b/gcc/testsuite/g++.dg/init/array21.C
@@ -2,6 +2,6 @@
 
 void foo()
 {
-  const int x[] = 0; // { dg-error "size" }
+  const int x[] = 0; // { dg-error "initializer" }
   ++x;
 }
diff --git a/gcc/testsuite/g++.dg/init/array32.C b/gcc/testsuite/g++.dg/init/array32.C
new file mode 100644
index 0000000..06b27a9
--- /dev/null
+++ b/gcc/testsuite/g++.dg/init/array32.C
@@ -0,0 +1,7 @@
+// PR c++/42315
+
+extern int x[];
+
+int i = x[0];
+
+int x[] = 0;			// { dg-error "" }