generic args available to member functions

See #22

src/analyze.cpp

@@ -1549,7 +1549,7 @@ static void preview_fn_proto(CodeGen *g, ImportTableEntry *import, AstNode *prot
     if (proto_node->data.fn_proto.generic_params.length > 0) {
         return preview_generic_fn_proto(g, import, proto_node);
     } else {
-        return preview_fn_proto_instance(g, import, proto_node, import->block_context);
+        return preview_fn_proto_instance(g, import, proto_node, proto_node->block_context);
     }
 
 }

test/self_hosted.zig

@@ -1572,9 +1572,11 @@ fn generic_struct() {
     var a1 = GenNode(i32) {.value = 13, .next = null,};
     var b1 = GenNode(bool) {.value = true, .next = null,};
     assert(a1.value == 13);
-    assert(b1.value);
+    assert(a1.value == a1.get_val());
+    assert(b1.get_val());
 }
 struct GenNode(T: type) {
     value: T,
     next: ?&GenNode(T),
+    fn get_val(n: &const GenNode(T)) -> T { n.value }
 }