compiler: improvements for type alias handling

    
    Give an error for an attempt to define a method on an imported type.
    
    Give an error for each attempt to define a method on a builtin type.
    
    Adjust error messages to be closer to gc error messages.
    
    With these changes gccgo passes current tests on dev.typealias branch.
    
    This changes the errors printed for test/fixedbugs/issue5089.go, but
    the change is an improvement:
    
        Before:
            fixedbugs/issue5089.go:13:1: error: redefinition of ‘bufio.Buffered’: receiver name changed
             func (b *bufio.Reader) Buffered() int { // ERROR "non-local|redefinition"
             ^
            fixedbugs/issue5089.go:11:13: note: previous definition of ‘bufio.Buffered’ was here
             import "bufio" // GCCGO_ERROR "previous"
                         ^
    
        Now:
            fixedbugs/issue5089.go:13:7: error: may not define methods on non-local type
             func (b *bufio.Reader) Buffered() int { // ERROR "non-local|redefinition"
                   ^
    
    Reviewed-on: https://go-review.googlesource.com/35642

From-SVN: r244889

1 files changed, 2 insertions, 2 deletions

diff --git a/gcc/testsuite/go.test/test/fixedbugs/issue5089.go b/gcc/testsuite/go.test/test/fixedbugs/issue5089.go
index 81b9f05..dc393e9 100644
--- a/gcc/testsuite/go.test/test/fixedbugs/issue5089.go
+++ b/gcc/testsuite/go.test/test/fixedbugs/issue5089.go
@@ -1,6 +1,6 @@
 // errorcheck
 
-// Copyright 2013 The Go Authors.  All rights reserved.
+// Copyright 2013 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.
 
@@ -8,7 +8,7 @@
 
 package p
 
-import "bufio"	// GCCGO_ERROR "previous"
+import "bufio"
 
 func (b *bufio.Reader) Buffered() int { // ERROR "non-local|redefinition"
 	return -1