Go patch committed: Don't permit embedded pointer to interface

[Ian Lance Taylor <iant at google dot com>]

The Go language has changed to specify that the type of an embedded
field in a struct may not be a pointer to an interface type.  This patch
implements that restrictions in gccgo.  Bootstrapped and ran Go
testsuite on x86_64-unknown-linux-gnu.  Committed to mainline.

Ian

diff -r e318745d1f78 go/expressions.cc
--- a/go/expressions.cc	Fri Mar 25 23:05:28 2011 -0700
+++ b/go/expressions.cc	Sat Mar 26 11:29:36 2011 -0700
@@ -10135,7 +10135,10 @@
 
   Interface_type* interface_type = type->interface_type();
   if (interface_type == NULL)
-    this->report_error(_("expected interface or pointer to interface"));
+    {
+      if (!type->is_error_type())
+	this->report_error(_("expected interface or pointer to interface"));
+    }
   else
     {
       const Typed_identifier* method =
diff -r e318745d1f78 go/types.cc
--- a/go/types.cc	Fri Mar 25 23:05:28 2011 -0700
+++ b/go/types.cc	Sat Mar 26 11:29:36 2011 -0700
@@ -3464,6 +3464,14 @@
 	      p->set_type(Type::make_error_type());
 	      return false;
 	    }
+	  if (t->points_to() != NULL
+	      && t->points_to()->interface_type() != NULL)
+	    {
+	      error_at(p->location(),
+		       "embedded type may not be pointer to interface");
+	      p->set_type(Type::make_error_type());
+	      return false;
+	    }
 	}
     }
   return ret;
Index: gcc/testsuite/go.test/test/interface/embed.go
===================================================================
--- gcc/testsuite/go.test/test/interface/embed.go	(revision 171359)
+++ gcc/testsuite/go.test/test/interface/embed.go	(working copy)
@@ -4,7 +4,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Check methods derived from embedded interface and *interface values.
+// Check methods derived from embedded interface values.
 
 package main
 
@@ -19,18 +19,12 @@ func (t T) M() int64 { return int64(t) }
 var t = T(Value)
 var pt = &t
 var ti Inter = t
-var pti = &ti
 
 type S struct { Inter }
 var s = S{ ti }
 var ps = &s
 
-type SP struct { *Inter }
-var sp = SP{ &ti }
-var psp = &sp
-
 var i Inter
-var pi = &i
 
 var ok = true
 
@@ -45,35 +39,20 @@ func main() {
 	check("t.M()", t.M())
 	check("pt.M()", pt.M())
 	check("ti.M()", ti.M())
-	check("pti.M()", pti.M())
 	check("s.M()", s.M())
 	check("ps.M()", ps.M())
-	check("sp.M()", sp.M())
-	check("psp.M()", psp.M())
 
 	i = t
 	check("i = t; i.M()", i.M())
-	check("i = t; pi.M()", pi.M())
 
 	i = pt
 	check("i = pt; i.M()", i.M())
-	check("i = pt; pi.M()", pi.M())
 
 	i = s
 	check("i = s; i.M()", i.M())
-	check("i = s; pi.M()", pi.M())
 
 	i = ps
 	check("i = ps; i.M()", i.M())
-	check("i = ps; pi.M()", pi.M())
-
-	i = sp
-	check("i = sp; i.M()", i.M())
-	check("i = sp; pi.M()", pi.M())
-
-	i = psp
-	check("i = psp; i.M()", i.M())
-	check("i = psp; pi.M()", pi.M())
 
 	if !ok {
 		println("BUG: interface10")