[mypyc] Implement list insert primitive

mypyc/lib-rt/CPy.h

@@ -323,6 +323,7 @@ bool CPyList_SetItem(PyObject *list, CPyTagged index, PyObject *value);
 PyObject *CPyList_PopLast(PyObject *obj);
 PyObject *CPyList_Pop(PyObject *obj, CPyTagged index);
 CPyTagged CPyList_Count(PyObject *obj, PyObject *value);
+CPyTagged CPyList_Insert(PyObject *list, CPyTagged index, PyObject *value);
 PyObject *CPyList_Extend(PyObject *o1, PyObject *o2);
 PyObject *CPySequence_Multiply(PyObject *seq, CPyTagged t_size);
 PyObject *CPySequence_RMultiply(CPyTagged t_size, PyObject *seq);

mypyc/lib-rt/list_ops.c

@@ -108,6 +108,15 @@ CPyTagged CPyList_Count(PyObject *obj, PyObject *value)
     return list_count((PyListObject *)obj, value);
 }
 
+CPyTagged CPyList_Insert(PyObject *list, CPyTagged index, PyObject *value)
+{
+    if (CPyTagged_CheckShort(index)) {
+        Py_ssize_t n = CPyTagged_ShortAsSsize_t(index);
+        return PyList_Insert(list, n, value);
+    }
+    return -1;
+}
+
 PyObject *CPyList_Extend(PyObject *o1, PyObject *o2) {
     return _PyList_Extend((PyListObject *)o1, o2);
 }

mypyc/primitives/list_ops.py

@@ -105,6 +105,14 @@
     c_function_name='CPyList_Count',
     error_kind=ERR_MAGIC)
 
+# list.insert(index, obj)
+method_op(
+    name='insert',
+    arg_types=[list_rprimitive, int_rprimitive, object_rprimitive],
+    return_type=int_rprimitive,
+    c_function_name='CPyList_Insert',
+    error_kind=ERR_MAGIC)
+
 # list * int
 binary_op(
     name='*',

mypyc/test-data/irbuild-lists.test

@@ -233,3 +233,18 @@ L0:
     r2 = r1 >= 0 :: signed
     r3 = truncate r1: int32 to builtins.bool
     return r3
+
+[case testListInsert]
+from typing import List
+def f(x: List[int], y: int) -> None:
+    x.insert(0, y)
+[out]
+def f(x, y):
+    x :: list
+    y :: int
+    r0 :: object
+    r1 :: int
+L0:
+    r0 = box(int, y)
+    r1 = CPyList_Insert(x, 0, r0)
+    return 1

mypyc/test-data/run-lists.test

@@ -103,6 +103,12 @@ pop(l, -2)
 assert l == [1, 3]
 assert count(l, 1) == 1
 assert count(l, 2) == 0
+l.insert(0, 0)
+assert l == [0, 1, 3]
+l.insert(2, 2)
+assert l == [0, 1, 2, 3]
+l.insert(4, 4)
+assert l == [0, 1, 2, 3, 4]
 
 [case testListOfUserDefinedClass]
 class C: