T,ok = I.(T)

R=r
OCL=18580
CL=18582

diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c
index ceae4480a5aca2772a8b8309aab9e8fec13a3030..f382390627814288772df3a3785c7661bc7f2682 100644 (file)
--- a/src/cmd/gc/walk.c
+++ b/src/cmd/gc/walk.c
@@ -14,8 +14,10 @@ enum
 {
        Inone,
        I2T,
+       I2T2,
        I2I,
-       T2I
+       I2I2,
+       T2I,
 };
 
 // can this code branch reach the end
@@ -463,6 +465,33 @@ loop:
                                goto ret;
                        }
                        break;
+
+               case OCONV:
+                       if(cl == 2 && cr == 1) {
+                               // a,b = i.(T)
+                               if(r->left == N)
+                                       break;
+                               et = isandss(r->type, r->left);
+                               switch(et) {
+                               case I2T:
+                                       et = I2T2;
+                                       break;
+                               case I2I:
+                                       et = I2I2;
+                                       break;
+                               default:
+                                       et = Inone;
+                                       break;
+                               }
+                               if(et == Inone)
+                                       break;
+                               r = ifaceop(r->type, r->left, et);
+                               l = ascompatet(n->op, &n->left, &r->type, 0);
+                               if(l != N)
+                                       indir(n, list(r, reorder2(l)));
+                               goto ret;
+                       }
+                       break;
                }
 
                switch(l->op) {
@@ -2667,6 +2696,15 @@ isandss(Type *lt, Node *r)
        return Inone;
 }
 
+static char*
+ifacename[] =
+{
+       [I2T]   = "ifaceI2T",
+       [I2T2]  = "ifaceI2T2",
+       [I2I]   = "ifaceI2I",
+       [I2I2]  = "ifaceI2I2",
+};
+
 Node*
 ifaceop(Type *tl, Node *n, int op)
 {
@@ -2678,26 +2716,7 @@ ifaceop(Type *tl, Node *n, int op)
 
        switch(op) {
        default:
-               fatal("ifaceop: unknown op %d\n", op);
-
-       case I2T:
-               // ifaceI2T(sigt *byte, iface any) (ret any);
-
-               a = n;                          // interface
-               r = a;
-
-               s = signame(tl);                // sigi
-               if(s == S)
-                       fatal("ifaceop: signame I2T");
-               a = s->oname;
-               a = nod(OADDR, a, N);
-               r = list(a, r);
-
-               on = syslook("ifaceI2T", 1);
-               argtype(on, tr);
-               argtype(on, tl);
-
-               break;
+               fatal("ifaceop: unknown op %O\n", op);
 
        case T2I:
                // ifaceT2I(sigi *byte, sigt *byte, elem any) (ret any);
@@ -2726,22 +2745,26 @@ ifaceop(Type *tl, Node *n, int op)
 
                break;
 
+       case I2T:
+       case I2T2:
        case I2I:
-               // ifaceI2I(sigi *byte, iface any-1) (ret any-2);
+       case I2I2:
+               // iface[IT]2[IT][2](sigt *byte, iface any) (ret any[, ok bool]);
 
                a = n;                          // interface
                r = a;
 
                s = signame(tl);                // sigi
                if(s == S)
-                       fatal("ifaceop: signame I2I");
+                       fatal("ifaceop: signame %d", op);
                a = s->oname;
                a = nod(OADDR, a, N);
                r = list(a, r);
 
-               on = syslook("ifaceI2I", 1);
+               on = syslook(ifacename[op], 1);
                argtype(on, tr);
                argtype(on, tl);
+
                break;
 
        case OEQ: