py: Don't try to optimise for+range when args are not simple expressions.

Addresses issue #1693.

2 files changed, 71 insertions, 0 deletions

diff --git a/py/compile.c b/py/compile.c
index 5c2fce6866..841b8f90c0 100644
--- a/py/compile.c
+++ b/py/compile.c
@@ -1421,6 +1421,19 @@ STATIC void compile_for_stmt(compiler_t *comp, mp_parse_node_struct_t *pns) {
                         optimize = false;
                     }
                 }
+                // arguments must be able to be compiled as standard expressions
+                if (optimize && MP_PARSE_NODE_IS_STRUCT(pn_range_start)) {
+                    int k = MP_PARSE_NODE_STRUCT_KIND((mp_parse_node_struct_t*)pn_range_start);
+                    if (k == PN_arglist_star || k == PN_arglist_dbl_star || k == PN_argument) {
+                        optimize = false;
+                    }
+                }
+                if (optimize && MP_PARSE_NODE_IS_STRUCT(pn_range_end)) {
+                    int k = MP_PARSE_NODE_STRUCT_KIND((mp_parse_node_struct_t*)pn_range_end);
+                    if (k == PN_arglist_star || k == PN_arglist_dbl_star || k == PN_argument) {
+                        optimize = false;
+                    }
+                }
             }
             if (optimize) {
                 compile_for_stmt_optimised_range(comp, pns->nodes[0], pn_range_start, pn_range_end, pn_range_step, pns->nodes[2], pns->nodes[3]);
diff --git a/tests/basics/for_range.py b/tests/basics/for_range.py
new file mode 100644
index 0000000000..ddff5ebd44
--- /dev/null
+++ b/tests/basics/for_range.py
@@ -0,0 +1,58 @@
+# test for+range, mostly to check optimisation of this pair
+
+# apply args using *
+for x in range(*(1, 3)):
+    print(x)
+for x in range(1, *(6, 2)):
+    print(x)
+
+# apply args using **
+try:
+    for x in range(**{'end':1}):
+        print(x)
+except TypeError:
+    print('TypeError')
+try:
+    for x in range(0, **{'end':1}):
+        print(x)
+except TypeError:
+    print('TypeError')
+try:
+    for x in range(0, 1, **{'step':1}):
+        print(x)
+except TypeError:
+    print('TypeError')
+
+# keyword args
+try:
+    for x in range(end=1):
+        print(x)
+except TypeError:
+    print('TypeError')
+try:
+    for x in range(0, end=1):
+        print(x)
+except TypeError:
+    print('TypeError')
+try:
+    for x in range(0, 1, step=1):
+        print(x)
+except TypeError:
+    print('TypeError')
+
+# argument is a comprehension
+try:
+    for x in range(0 for i in []):
+        print(x)
+except TypeError:
+    print('TypeError')
+try:
+    for x in range(0, (0 for i in [])):
+        print(x)
+except TypeError:
+    print('TypeError')
+try:
+    for x in range(0, 1, (0 for i in [])):
+        print(x)
+except TypeError:
+    print('TypeError')