gc: new, less strict bool rules

R=ken2
CC=golang-dev
https://golang.org/cl/5688064

src/cmd/gc/const.c

@@ -87,6 +87,8 @@ convlit1(Node **np, Type *t, int explicit)
 
 	switch(n->op) {
 	default:
+		if(n->type == idealbool)
+			n->type = types[TBOOL];
 		if(n->type->etype == TIDEAL) {
 			convlit(&n->left, t);
 			convlit(&n->right, t);
@@ -1010,6 +1012,10 @@ defaultlit(Node **np, Type *t)
 		}
 		n->type = t;
 		return;
+	case ONOT:
+		defaultlit(&n->left, t);
+		n->type = n->left->type;
+		return;
 	default:
 		if(n->left == N) {
 			dump("defaultlit", n);
@@ -1029,13 +1035,18 @@ defaultlit(Node **np, Type *t)
 		} else if(t == T && (n->left->op == OLSH || n->left->op == ORSH)) {
 			defaultlit(&n->right, T);
 			defaultlit(&n->left, n->right->type);
+		} else if(iscmp[n->op]) {
+			defaultlit2(&n->left, &n->right, 1);
 		} else {
 			defaultlit(&n->left, t);
 			defaultlit(&n->right, t);
 		}
-		if(n->type == idealbool || n->type == idealstring)
+		if(n->type == idealbool || n->type == idealstring) {
-			n->type = types[n->type->etype];
+			if(t != T && t->etype == n->type->etype)
-		else
+				n->type = t;
+			else
+				n->type = types[n->type->etype];
+		} else
 			n->type = n->left->type;
 		return;
 	}
@@ -1124,6 +1135,10 @@ defaultlit2(Node **lp, Node **rp, int force)
 	}
 	if(!force)
 		return;
+	if(l->type->etype == TBOOL) {
+		convlit(lp, types[TBOOL]);
+		convlit(rp, types[TBOOL]);
+	}
 	if(isconst(l, CTCPLX) || isconst(r, CTCPLX)) {
 		convlit(lp, types[TCOMPLEX128]);
 		convlit(rp, types[TCOMPLEX128]);

src/cmd/gc/subr.c

@@ -1354,6 +1354,18 @@ assignconv(Node *n, Type *t, char *context)
 	if(t->etype == TBLANK)
 		return n;
 
+	// Convert ideal bool from comparison to plain bool
+	// if the next step is non-bool (like interface{}).
+	if(n->type == idealbool && t->etype != TBOOL) {
+		if(n->op == ONAME || n->op == OLITERAL) {
+			r = nod(OCONVNOP, n, N);
+			r->type = types[TBOOL];
+			r->typecheck = 1;
+			r->implicit = 1;
+			n = r;
+		}
+	}
+
 	if(eqtype(n->type, t))
 		return n;
 

src/cmd/gc/typecheck.c

@@ -526,7 +526,7 @@ reswitch:
 		t = l->type;
 		if(iscmp[n->op]) {
 			evconst(n);
-			t = types[TBOOL];
+			t = idealbool;
 			if(n->op != OLITERAL) {
 				defaultlit2(&l, &r, 1);
 				n->left = l;
@@ -1317,6 +1317,13 @@ reswitch:
 	case OPRINTN:
 		ok |= Etop;
 		typechecklist(n->list, Erv | Eindir);  // Eindir: address does not escape
+		for(args=n->list; args; args=args->next) {
+			// Special case for print: int constant is int64, not int.
+			if(isconst(args->n, CTINT))
+				defaultlit(&args->n, types[TINT64]);
+			else
+				defaultlit(&args->n, T);
+		}
 		goto ret;
 
 	case OPANIC:
@@ -2887,6 +2894,8 @@ typecheckdef(Node *n)
 	}
 
 ret:
+	if(n->op != OLITERAL && n->type != T && isideal(n->type))
+		fatal("got %T for %N", n->type, n);
 	if(typecheckdefstack->n != n)
 		fatal("typecheckdefstack mismatch");
 	l = typecheckdefstack;

src/cmd/gc/walk.c

@@ -1055,6 +1055,8 @@ walkexpr(Node **np, NodeList **init)
 			walkexpr(&r, nil);
 		}
 		typecheck(&r, Erv);
+		if(n->type->etype != TBOOL) fatal("cmp %T", n->type);
+		r->type = n->type;
 		n = r;
 		goto ret;
 
@@ -1190,7 +1192,7 @@ walkexpr(Node **np, NodeList **init)
 			r = nod(OOROR, nod(ONE, nod(OITAB, n->left, N), nod(OITAB, n->right, N)), r);
 		typecheck(&r, Erv);
 		walkexpr(&r, nil);
-
+		r->type = n->type;
 		n = r;
 		goto ret;
 

test/named1.go

@@ -37,8 +37,8 @@ func main() {
 	asBool(true)
 	asBool(*&b)
 	asBool(Bool(true))
-	asBool(1 != 2) // ERROR "cannot use.*type bool.*as type Bool"
+	asBool(1 != 2) // ok now
-	asBool(i < j)  // ERROR "cannot use.*type bool.*as type Bool"
+	asBool(i < j)  // ok now
 
 	_, b = m[2] // ERROR "cannot .* bool.*type Bool"