do not set t->recur on basic types.

the comment talked about printing, but now
t->recur is only used for typehash.
in typehash it is important to compute different
hashes for the different basic types.

add test that makes sure an interface { X() int8 }
cannot be used as interface { X() int64 }

R=ken
OCL=17396
CL=17396

src/cmd/gc/lex.c

@@ -1120,7 +1120,6 @@ lexinit(void)
 		}
 
 		t->sym = s;
-		t->recur = 1;	// supresses printing beyond name
 
 		dowidth(t);
 		types[etype] = t;

test/golden.out

@@ -34,6 +34,14 @@ Faulting address: 0x0
 pc: xxx
 
 
+=========== ./interface3.go
+cannot convert type S to interface I2: missing method Name
+throw: interface conversion
+SIGSEGV: segmentation violation
+Faulting address: 0x0
+pc: xxx
+
+
 =========== ./peano.go
 0! = 1
 1! = 1

test/interface3.go

+// $G $D/$F.go && $L $F.$A && (! ./$A.out || echo BUG: should not succeed)
+
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+type S struct { a int }
+type T struct { b string }
+
+func (s *S) Name() int8 { return 1 }
+func (t *T) Name() int64 { return 64 }
+
+type I1 interface { Name() int8 }
+type I2 interface { Name() int64 }
+
+func main() {
+	var i1 I1;
+	var s *S;
+	i1 = s;
+	print(i1.(I2).Name())
+}