From 0b209b36b6ae03f81d93f07bcbbdcb8fa8a1aebe Mon Sep 17 00:00:00 2001
From: Anthony Martin <ality@pbrane.org>
Date: Tue, 24 May 2011 19:48:19 -0400
Subject: [PATCH] gc: relax assignability of method receivers

The spec was adjusted in commit df410d6a4842 to allow the
implicit assignment of strutures with unexported fields in
method receivers.  This change updates the compiler.

Also moved bug322 into fixedbugs and updated golden.out
to reflect the removal of the last known bug.

Fixes #1402.

R=golang-dev, gri, rsc
CC=golang-dev
https://golang.org/cl/4526069
---
 src/cmd/gc/typecheck.c                      | 8 +++++++-
 test/fixedbugs/bug226.dir/y.go              | 2 +-
 test/{bugs => fixedbugs}/bug322.dir/lib.go  | 0
 test/{bugs => fixedbugs}/bug322.dir/main.go | 7 -------
 test/{bugs => fixedbugs}/bug322.go          | 0
 test/golden.out                             | 5 -----
 6 files changed, 8 insertions(+), 14 deletions(-)
 rename test/{bugs => fixedbugs}/bug322.dir/lib.go (100%)
 rename test/{bugs => fixedbugs}/bug322.dir/main.go (69%)
 rename test/{bugs => fixedbugs}/bug322.go (100%)

diff --git a/src/cmd/gc/typecheck.c b/src/cmd/gc/typecheck.c
index 9aaf3e6efe..0cf11684da 100644
--- a/src/cmd/gc/typecheck.c
+++ b/src/cmd/gc/typecheck.c
@@ -822,7 +822,13 @@ reswitch:
 
 		case ODOTMETH:
 			n->op = OCALLMETH;
-			typecheckaste(OCALL, n->left, 0, getthisx(t), list1(l->left), "method receiver");
+			// typecheckaste was used here but there wasn't enough
+			// information further down the call chain to know if we
+			// were testing a method receiver for unexported fields.
+			// It isn't necessary, so just do a sanity check.
+			tp = getthisx(t)->type->type;
+			if(l->left == N || !eqtype(l->left->type, tp))
+				fatal("method receiver");
 			break;
 
 		default:
diff --git a/test/fixedbugs/bug226.dir/y.go b/test/fixedbugs/bug226.dir/y.go
index 01e8b7b437..c66d592b7c 100644
--- a/test/fixedbugs/bug226.dir/y.go
+++ b/test/fixedbugs/bug226.dir/y.go
@@ -15,7 +15,7 @@ func f() {
 	_ = x.T{};
 	_ = x.T{Y:2};
 	
-	ok1.M();	// ERROR "assignment.*T"
+	ok1.M();
 	bad1 := *ok;	// ERROR "assignment.*T"
 	bad2 := ok1;	// ERROR "assignment.*T"
 	*ok4 = ok1;	// ERROR "assignment.*T"
diff --git a/test/bugs/bug322.dir/lib.go b/test/fixedbugs/bug322.dir/lib.go
similarity index 100%
rename from test/bugs/bug322.dir/lib.go
rename to test/fixedbugs/bug322.dir/lib.go
diff --git a/test/bugs/bug322.dir/main.go b/test/fixedbugs/bug322.dir/main.go
similarity index 69%
rename from test/bugs/bug322.dir/main.go
rename to test/fixedbugs/bug322.dir/main.go
index 0ab5b32e45..f403c7d32e 100644
--- a/test/bugs/bug322.dir/main.go
+++ b/test/fixedbugs/bug322.dir/main.go
@@ -38,10 +38,3 @@ func main() {
 	var pi2 PI = pt
 	pi2.PM()
 }
-
-/*
-These should not be errors anymore:
-
-bug322.dir/main.go:19: implicit assignment of unexported field 'x' of lib.T in method receiver
-bug322.dir/main.go:32: implicit assignment of unexported field 'x' of lib.T in method receiver
-*/
diff --git a/test/bugs/bug322.go b/test/fixedbugs/bug322.go
similarity index 100%
rename from test/bugs/bug322.go
rename to test/fixedbugs/bug322.go
diff --git a/test/golden.out b/test/golden.out
index 725e8de448..4400e41dd1 100644
--- a/test/golden.out
+++ b/test/golden.out
@@ -161,8 +161,3 @@ panic: interface conversion: interface is main.T, not main.T
 0x0
 
 == bugs/
-
-=========== bugs/bug322.go
-bugs/bug322.dir/main.go:19: implicit assignment of unexported field 'x' of lib.T in method receiver
-bugs/bug322.dir/main.go:32: implicit assignment of unexported field 'x' of lib.T in method receiver
-BUG: fails incorrectly