mixed old/new declaration

exact spec:
a) must be a multi-assignment w :=
b) a proper subset of the lhs
   can be declared in same block
   with the same type with no
   "redeclaration" error

R=r
OCL=27610
CL=27610

diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c
index f64ada8a48356c9b75583c5f1ed6af36e96a72c2..1e013e8c32cd0ca14bb05a02e5b511dd7d25b9ee 100644 (file)
--- a/src/cmd/gc/walk.c
+++ b/src/cmd/gc/walk.c
@@ -3063,6 +3063,82 @@ old2new(Node *n, Type *t)
        return l;
 }
 
+static Node*
+mixedoldnew(Node *n, Type *t)
+{
+       n = nod(OXXX, n, N);
+       n->type = t;
+       return n;
+}
+
+static Node*
+checkmixed(Node *nl)
+{
+       Iter save;
+       Node *l, *n, *a;
+       Type *t;
+       int ntot, nred;
+
+       nl = rev(nl);
+
+       // first pass, check if it is a special
+       // case of new and old declarations
+
+       ntot = 0;       // number assignments
+       nred = 0;       // number redeclarations
+       l = listfirst(&save, &nl);
+       while(l != N) {
+               t = l->type;
+               l = l->left;
+
+               if(l->op != ONAME && l->op != ONONAME)
+                       goto allnew;
+               if(l->sym->block == block) {
+                       if(!eqtype(l->type, t, 0))
+                               goto allnew;
+                       nred++;
+               }
+               ntot++;
+               l = listnext(&save);
+       }
+
+       // test for special case
+       // a) multi-assignment (ntot>1)
+       // b) at least one redeclaration (red>0)
+       // c) not all redeclarations (nred!=ntot)
+       if(nred == 0 || ntot <= 1 || nred == ntot)
+               goto allnew;
+
+       n = N;
+       l = listfirst(&save, &nl);
+       while(l != N) {
+               t = l->type;
+               l = l->left;
+
+               a = l;
+               if(l->sym->block != block)
+                       a = old2new(l, t);
+
+               n = list(n, a);
+               l = listnext(&save);
+       }
+       return rev(n);
+
+allnew:
+       // same as original
+       n = N;
+       l = listfirst(&save, &nl);
+       while(l != N) {
+               t = l->type;
+               l = l->left;
+
+               a = old2new(l, t);
+               n = list(n, a);
+               l = listnext(&save);
+       }
+       return rev(n);
+}
+
 Node*
 colas(Node *nl, Node *nr)
 {
@@ -3105,12 +3181,12 @@ colas(Node *nl, Node *nr)
                        l = listfirst(&savel, &nl);
                        t = structfirst(&saver, getoutarg(t));
                        while(l != N) {
-                               a = old2new(l, t->type);
+                               a = mixedoldnew(l, t->type);
                                n = list(n, a);
                                l = listnext(&savel);
                                t = structnext(&saver);
                        }
-                       n = rev(n);
+                       n = checkmixed(n);
                        return n;
                }
        }
@@ -3126,13 +3202,13 @@ colas(Node *nl, Node *nr)
        while(l != N) {
                walktype(r, Erv);
                defaultlit(r, T);
-               a = old2new(l, r->type);
+               a = mixedoldnew(l, r->type);
                n = list(n, a);
 
                l = listnext(&savel);
                r = listnext(&saver);
        }
-       n = rev(n);
+       n = checkmixed(n);
        return n;
 
 multi:
@@ -3155,10 +3231,11 @@ multi:
                t = nr->left->type;
                if(!istype(t, TMAP))
                        goto badt;
-               a = old2new(nl->left, t->type);
+               a = mixedoldnew(nl->left, t->type);
                n = a;
-               a = old2new(nl->right, types[TBOOL]);
+               a = mixedoldnew(nl->right, types[TBOOL]);
                n = list(n, a);
+               n = checkmixed(n);
                break;
 
        case ODOTTYPE:
@@ -3169,10 +3246,11 @@ multi:
                if(!isinter(nr->left->type))
                        goto badt;
                // a,b = iface
-               a = old2new(nl->left, nr->type);
+               a = mixedoldnew(nl->left, nr->type);
                n = a;
-               a = old2new(nl->right, types[TBOOL]);
+               a = mixedoldnew(nl->right, types[TBOOL]);
                n = list(n, a);
+               n = checkmixed(n);
                break;
 
        case ORECV:
@@ -3182,10 +3260,11 @@ multi:
                t = nr->left->type;
                if(!istype(t, TCHAN))
                        goto badt;
-               a = old2new(nl->left, t->type);
+               a = mixedoldnew(nl->left, t->type);
                n = a;
-               a = old2new(nl->right, types[TBOOL]);
+               a = mixedoldnew(nl->right, types[TBOOL]);
                n = list(n, a);
+               n = checkmixed(n);
                break;
        }
        n = rev(n);