cmd/gc: implement len(array) / cap(array) rule
The spec is looser than the current implementation.
The spec edit was made in CL 4444050 (May 2011)
but I never implemented it.
Fixes #3244.
R=ken2
CC=golang-dev
https://golang.org/cl/5785049
diff --git a/src/cmd/gc/typecheck.c b/src/cmd/gc/typecheck.c
index 6dc3fd1..e98d538 100644
--- a/src/cmd/gc/typecheck.c
+++ b/src/cmd/gc/typecheck.c
@@ -190,6 +190,46 @@
return n;
}
+/*
+ * does n contain a call or receive operation?
+ */
+static int callrecvlist(NodeList*);
+
+static int
+callrecv(Node *n)
+{
+ if(n == nil)
+ return 0;
+
+ switch(n->op) {
+ case OCALL:
+ case OCALLMETH:
+ case OCALLINTER:
+ case OCALLFUNC:
+ case ORECV:
+ return 1;
+ }
+
+ return callrecv(n->left) ||
+ callrecv(n->right) ||
+ callrecv(n->ntest) ||
+ callrecv(n->nincr) ||
+ callrecvlist(n->ninit) ||
+ callrecvlist(n->nbody) ||
+ callrecvlist(n->nelse) ||
+ callrecvlist(n->list) ||
+ callrecvlist(n->rlist);
+}
+
+static int
+callrecvlist(NodeList *l)
+{
+ for(; l; l=l->next)
+ if(callrecv(l->n))
+ return 1;
+ return 0;
+}
+
static void
typecheck1(Node **np, int top)
{
@@ -995,12 +1035,14 @@
}
break;
case TARRAY:
- if(t->bound >= 0 && l->op == ONAME) {
- r = nod(OXXX, N, N);
- nodconst(r, types[TINT], t->bound);
- r->orig = n;
- n = r;
- }
+ if(t->bound < 0) // slice
+ break;
+ if(callrecv(l)) // has call or receive
+ break;
+ r = nod(OXXX, N, N);
+ nodconst(r, types[TINT], t->bound);
+ r->orig = n;
+ n = r;
break;
}
n->type = types[TINT];
