[mypyc] Fix calling a property that returns a callable

mypyc/irbuild/expression.py

@@ -617,6 +617,10 @@ def translate_super_method_call(builder: IRBuilder, expr: CallExpr, callee: Supe
         return translate_call(builder, expr, callee)
 
     decl = base.method_decl(callee.name)
+    if decl.is_prop_getter:
+        # super().prop(...) calls the property's value, so get it through super()
+        return translate_call(builder, expr, callee)
+
     arg_values = [builder.accept(arg) for arg in expr.args]
     arg_kinds, arg_names = expr.arg_kinds.copy(), expr.arg_names.copy()
 

mypyc/irbuild/ll_builder.py

@@ -1489,7 +1489,12 @@ def gen_method_call(
             and not base.type.class_ir.builtin_base
         ):
             name = name if base.type.class_ir.is_ext_class else fast_name
-            if base.type.class_ir.has_method(name):
+            # Property getters are also stored as methods, but obj.prop(...) calls the
+            # property's value, so handle properties like attributes below.
+            if (
+                base.type.class_ir.has_method(name)
+                and not base.type.class_ir.method_decl(name).is_prop_getter
+            ):
                 decl = base.type.class_ir.method_decl(name)
                 if arg_kinds is None:
                     assert arg_names is None, "arg_kinds not present but arg_names is"

mypyc/test-data/irbuild-classes.test

@@ -1352,6 +1352,42 @@ L0:
     r2 = r1.x
     return r2
 
+[case testPropertyReturningCallable]
+from typing import Callable
+
+class C:
+    _f: Callable[[int], int]
+
+    @property
+    def f(self) -> Callable[[int], int]:
+        return self._f
+
+def g(c: C) -> int:
+    return c.f(1)
+[out]
+def C.f(self):
+    self :: __main__.C
+    r0 :: object
+L0:
+    r0 = self._f
+    return r0
+def g(c):
+    c :: __main__.C
+    r0, r1 :: object
+    r2 :: object[1]
+    r3 :: object_ptr
+    r4 :: object
+    r5 :: int
+L0:
+    r0 = c.f
+    r1 = object 1
+    r2 = [r1]
+    r3 = load_address r2
+    r4 = PyObject_Vectorcall(r0, r3, 1, 0)
+    keep_alive r1
+    r5 = unbox(int, r4)
+    return r5
+
 [case testBorrowResultOfCustomGetItemInIfStatement_withgil]
 from typing import List
 

mypyc/test-data/run-classes.test

@@ -2129,6 +2129,89 @@ Represents a sequence of values. Updates itself by next, which is a new value.
 3
 3
 
+[case testPropertyReturningCallable]
+from typing import Any, Callable
+from mypy_extensions import trait
+
+class Config:
+    def __init__(self) -> None:
+        self._sorting_function: Callable[..., list[str]] | None = None
+
+    @property
+    def sorting_function(self) -> Callable[..., list[str]]:
+        if self._sorting_function is not None:
+            return self._sorting_function
+        self._sorting_function = sorted
+        return self._sorting_function
+
+    def sort(self, items: list[str]) -> list[str]:
+        return self.sorting_function(items)
+
+class Item:
+    def __init__(self, n: int) -> None:
+        self.n = n
+
+class C:
+    @property
+    def no_args(self) -> Callable[[], str]:
+        return lambda: "called"
+
+    @property
+    def any_value(self) -> Any:
+        return lambda x: x * 2
+
+    @property
+    def item_type(self) -> type[Item]:
+        return Item
+
+class Base:
+    @property
+    def f(self) -> Callable[[int], int]:
+        return lambda x: x + 1
+
+class Derived(Base):
+    def call_super(self, x: int) -> int:
+        return super().f(x)
+
+class AttrOverride(Base):
+    # A builtin, so that it isn't bound as a method when interpreted
+    f: Callable[[int], int] = abs
+
+@trait
+class T:
+    @property
+    def f(self) -> Callable[[int], int]:
+        return lambda x: x - 1
+
+class UsesTrait(T):
+    pass
+
+def call_f(b: Base, x: int) -> int:
+    return b.f(x)
+
+def call_trait_f(t: T, x: int) -> int:
+    return t.f(x)
+
+def test_property_returning_callable() -> None:
+    config = Config()
+    assert config.sorting_function(["b2", "b10", "b1"]) == ["b1", "b10", "b2"]
+    assert config.sorting_function(["a", "b"], reverse=True) == ["b", "a"]
+    assert config.sort(["b", "a"]) == ["a", "b"]
+
+def test_property_returning_other_callables() -> None:
+    c = C()
+    assert c.no_args() == "called"
+    assert c.any_value(21) == 42
+    assert c.item_type(5).n == 5
+
+def test_property_returning_callable_inherited() -> None:
+    assert call_f(Base(), 1) == 2
+    assert call_f(Derived(), 1) == 2
+    assert Derived().call_super(2) == 3
+    assert call_f(AttrOverride(), -5) == 5
+    assert AttrOverride().f(-6) == 6
+    assert call_trait_f(UsesTrait(), 1) == 0
+
 [case testPropertySetters]
 
 from mypy_extensions import trait