cmd/gc: comma-ok assignments produce untyped bool as 2nd result

LGTM=rsc
R=gri, rsc
CC=golang-codereviews
https://golang.org/cl/127950043

diff --git a/src/cmd/gc/order.c b/src/cmd/gc/order.c
index 728defe7c303b76fcb6e7b6f9a0f853c803fc8a4..59231a0f1c982f7d6f8979b6e330afd520704f4f 100644 (file)
--- a/src/cmd/gc/order.c
+++ b/src/cmd/gc/order.c
@@ -593,7 +593,10 @@ orderstmt(Node *n, Order *order)
                orderexpr(&n->rlist->n->left, order);  // arg to recv
                ch = n->rlist->n->left->type;
                tmp1 = ordertemp(ch->type, order, haspointers(ch->type));
-               tmp2 = ordertemp(types[TBOOL], order, 0);
+               if(!isblank(n->list->next->n))
+                       tmp2 = ordertemp(n->list->next->n->type, order, 0);
+               else
+                       tmp2 = ordertemp(types[TBOOL], order, 0);
                order->out = list(order->out, n);
                r = nod(OAS, n->list->n, tmp1);
                typecheck(&r, Etop);

diff --git a/src/cmd/gc/typecheck.c b/src/cmd/gc/typecheck.c
index 92e9ad5215f7c030cdf1f0ea0ec87f36ce47168f..c295cf6d21e0fc5ff6564853dde7a7358cbf7364 100644 (file)
--- a/src/cmd/gc/typecheck.c
+++ b/src/cmd/gc/typecheck.c
@@ -2965,7 +2965,7 @@ typecheckas2(Node *n)
                        if(l->defn == n)
                                l->type = r->type;
                        l = n->list->next->n;
-                       if(l->type != T)
+                       if(l->type != T && l->type->etype != TBOOL)
                                checkassignto(types[TBOOL], l);
                        if(l->defn == n && l->ntype == N)
                                l->type = types[TBOOL];

diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c
index e50b917709bedaa5a79facb38c6a91941cf3455f..7ae75e561777afa63c5a5b60f72a3bf30aa7fccd 100644 (file)
--- a/src/cmd/gc/walk.c
+++ b/src/cmd/gc/walk.c
@@ -673,7 +673,7 @@ walkexpr(Node **np, NodeList **init)
                        n1 = nod(OADDR, n->list->n, N);
                n1->etype = 1; // addr does not escape
                fn = chanfn("chanrecv2", 2, r->left->type);
-               r = mkcall1(fn, types[TBOOL], init, typename(r->left->type), r->left, n1);
+               r = mkcall1(fn, n->list->next->n->type, init, typename(r->left->type), r->left, n1);
                n = nod(OAS, n->list->next->n, r);
                typecheck(&n, Etop);
                goto ret;
@@ -723,6 +723,12 @@ walkexpr(Node **np, NodeList **init)
                var->typecheck = 1;
                fn = mapfn(p, t);
                r = mkcall1(fn, getoutargx(fn->type), init, typename(t), r->left, key);
+
+               // mapaccess2* returns a typed bool, but due to spec changes,
+               // the boolean result of i.(T) is now untyped so we make it the
+               // same type as the variable on the lhs.
+               if(!isblank(n->list->next->n))
+                       r->type->type->down->type = n->list->next->n->type;
                n->rlist = list1(r);
                n->op = OAS2FUNC;
                n->list->n = var;
@@ -770,6 +776,12 @@ walkexpr(Node **np, NodeList **init)
                        *p = '\0';
                        
                        fn = syslook(buf, 1);
+
+                       // runtime.assert(E|I)2TOK returns a typed bool, but due
+                       // to spec changes, the boolean result of i.(T) is now untyped
+                       // so we make it the same type as the variable on the lhs.
+                       if(!isblank(n->list->next->n))
+                               fn->type->type->down->type->type = n->list->next->n->type;
                        ll = list1(typename(r->type));
                        ll = list(ll, r->left);
                        argtype(fn, r->left->type);

diff --git a/test/fixedbugs/issue8475.go b/test/fixedbugs/issue8475.go
new file mode 100644 (file)
index 0000000..e697945
--- /dev/null
+++ b/test/fixedbugs/issue8475.go
@@ -0,0 +1,25 @@
+// build
+
+// Copyright 2014 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.
+
+// Issue 8745: comma-ok assignments should produce untyped bool as 2nd result.
+
+package main
+
+type mybool bool
+
+func main() {
+       var ok mybool
+       _ = ok
+
+       var i interface{}
+       _, ok = i.(int)
+
+       var m map[int]int
+       _, ok = m[0]
+
+       var c chan int
+       _, ok = <-c
+}

diff --git a/test/named1.go b/test/named1.go
index 62b874c5cb9cbebf2bba8a4a87cf4ea544d38708..febad64ece60cd4f22f5b63fbadf9a893928a19f 100644 (file)
--- a/test/named1.go
+++ b/test/named1.go
@@ -41,21 +41,21 @@ func main() {
        asBool(1 != 2) // ok now
        asBool(i < j)  // ok now
 
-       _, b = m[2] // ERROR "cannot .* bool.*type Bool"
+       _, b = m[2] // ok now
 
        var inter interface{}
-       _, b = inter.(Map) // ERROR "cannot .* bool.*type Bool"
+       _, b = inter.(Map) // ok now
        _ = b
 
        var minter interface {
                M()
        }
-       _, b = minter.(Map) // ERROR "cannot .* bool.*type Bool"
+       _, b = minter.(Map) // ok now
        _ = b
 
        _, bb := <-c
        asBool(bb) // ERROR "cannot use.*type bool.*as type Bool"
-       _, b = <-c // ERROR "cannot .* bool.*type Bool"
+       _, b = <-c // ok now
        _ = b
 
        asString(String(slice)) // ok