From 55a08120b7be56e7d33cf2e9d240d30a8f608f83 Mon Sep 17 00:00:00 2001 From: Ivan Levkivskyi Date: Tue, 2 Jul 2024 19:36:16 +0100 Subject: [PATCH] Infer unions for ternary expressions (#17427) Ref https://github.com/python/mypy/issues/12056 cc @JukkaL Again, let's check the primer... --- mypy/checkexpr.py | 19 +++-- mypyc/test-data/irbuild-any.test | 4 +- test-data/unit/check-errorcodes.test | 2 +- test-data/unit/check-expressions.test | 17 ++-- test-data/unit/check-functions.test | 17 +++- test-data/unit/check-inference-context.test | 6 +- test-data/unit/check-inference.test | 10 ++- test-data/unit/check-optional.test | 2 +- test-data/unit/check-tuples.test | 87 ++++++++++++--------- 9 files changed, 99 insertions(+), 65 deletions(-) diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py index c4ab8a081acc..3532e18b93b2 100644 --- a/mypy/checkexpr.py +++ b/mypy/checkexpr.py @@ -5766,16 +5766,15 @@ def visit_conditional_expr(self, e: ConditionalExpr, allow_none_return: bool = F context=if_type_fallback, allow_none_return=allow_none_return, ) - - # Only create a union type if the type context is a union, to be mostly - # compatible with older mypy versions where we always did a join. - # - # TODO: Always create a union or at least in more cases? - if isinstance(get_proper_type(self.type_context[-1]), UnionType): - res: Type = make_simplified_union([if_type, full_context_else_type]) - else: - res = join.join_types(if_type, else_type) - + res: Type = make_simplified_union([if_type, else_type]) + if has_uninhabited_component(res) and not isinstance( + get_proper_type(self.type_context[-1]), UnionType + ): + # In rare cases with empty collections join may give a better result. + alternative = join.join_types(if_type, else_type) + p_alt = get_proper_type(alternative) + if not isinstance(p_alt, Instance) or p_alt.type.fullname != "builtins.object": + res = alternative return res def analyze_cond_branch( diff --git a/mypyc/test-data/irbuild-any.test b/mypyc/test-data/irbuild-any.test index 0d14e1a5dfc8..3bfb1587fb3b 100644 --- a/mypyc/test-data/irbuild-any.test +++ b/mypyc/test-data/irbuild-any.test @@ -151,7 +151,9 @@ def f4(a, n, b): a :: object n :: int b :: bool - r0, r1, r2, r3 :: object + r0 :: union[object, int] + r1, r2 :: object + r3 :: union[int, object] r4 :: int L0: if b goto L1 else goto L2 :: bool diff --git a/test-data/unit/check-errorcodes.test b/test-data/unit/check-errorcodes.test index 961815b11817..c4d72388fba9 100644 --- a/test-data/unit/check-errorcodes.test +++ b/test-data/unit/check-errorcodes.test @@ -460,7 +460,7 @@ a: D = {'x': ''} # E: Incompatible types (expression has type "str", TypedDict b: D = {'y': ''} # E: Missing key "x" for TypedDict "D" [typeddict-item] \ # E: Extra key "y" for TypedDict "D" [typeddict-unknown-key] c = D(x=0) if int() else E(x=0, y=0) -c = {} # E: Expected TypedDict key "x" but found no keys [typeddict-item] +c = {} # E: Missing key "x" for TypedDict "D" [typeddict-item] d: D = {'x': '', 'y': 1} # E: Extra key "y" for TypedDict "D" [typeddict-unknown-key] \ # E: Incompatible types (expression has type "str", TypedDict item "x" has type "int") [typeddict-item] diff --git a/test-data/unit/check-expressions.test b/test-data/unit/check-expressions.test index f9bd60f4dcc8..61cee1d00c58 100644 --- a/test-data/unit/check-expressions.test +++ b/test-data/unit/check-expressions.test @@ -1470,10 +1470,9 @@ if int(): [case testConditionalExpressionUnion] from typing import Union -reveal_type(1 if bool() else 2) # N: Revealed type is "builtins.int" -reveal_type(1 if bool() else '') # N: Revealed type is "builtins.object" -x: Union[int, str] = reveal_type(1 if bool() else '') \ - # N: Revealed type is "Union[Literal[1]?, Literal['']?]" +reveal_type(1 if bool() else 2) # N: Revealed type is "Union[Literal[1]?, Literal[2]?]" +reveal_type(1 if bool() else '') # N: Revealed type is "Union[Literal[1]?, Literal['']?]" +x: Union[int, str] = reveal_type(1 if bool() else '') # N: Revealed type is "Union[Literal[1]?, Literal['']?]" class A: pass class B(A): @@ -1487,17 +1486,17 @@ b = B() c = C() d = D() reveal_type(a if bool() else b) # N: Revealed type is "__main__.A" -reveal_type(b if bool() else c) # N: Revealed type is "builtins.object" -reveal_type(c if bool() else b) # N: Revealed type is "builtins.object" -reveal_type(c if bool() else a) # N: Revealed type is "builtins.object" -reveal_type(d if bool() else b) # N: Revealed type is "__main__.A" +reveal_type(b if bool() else c) # N: Revealed type is "Union[__main__.B, __main__.C]" +reveal_type(c if bool() else b) # N: Revealed type is "Union[__main__.C, __main__.B]" +reveal_type(c if bool() else a) # N: Revealed type is "Union[__main__.C, __main__.A]" +reveal_type(d if bool() else b) # N: Revealed type is "Union[__main__.D, __main__.B]" [builtins fixtures/bool.pyi] [case testConditionalExpressionUnionWithAny] from typing import Union, Any a: Any x: Union[int, str] = reveal_type(a if int() else 1) # N: Revealed type is "Union[Any, Literal[1]?]" -reveal_type(a if int() else 1) # N: Revealed type is "Any" +reveal_type(a if int() else 1) # N: Revealed type is "Union[Any, Literal[1]?]" [case testConditionalExpressionStatementNoReturn] from typing import List, Union diff --git a/test-data/unit/check-functions.test b/test-data/unit/check-functions.test index 93540e203c36..6c895c86e899 100644 --- a/test-data/unit/check-functions.test +++ b/test-data/unit/check-functions.test @@ -2250,13 +2250,26 @@ def dec(f: Callable[[A, str], None]) -> Callable[[A, int], None]: pass [out] [case testUnknownFunctionNotCallable] +from typing import TypeVar + def f() -> None: pass def g(x: int) -> None: pass h = f if bool() else g -reveal_type(h) # N: Revealed type is "builtins.function" -h(7) # E: Cannot call function of unknown type +reveal_type(h) # N: Revealed type is "Union[def (), def (x: builtins.int)]" +h(7) # E: Too many arguments for "f" + +T = TypeVar("T") +def join(x: T, y: T) -> T: ... + +h2 = join(f, g) +reveal_type(h2) # N: Revealed type is "builtins.function" +h2(7) # E: Cannot call function of unknown type + +h3 = join(g, f) +reveal_type(h3) # N: Revealed type is "builtins.function" +h3(7) # E: Cannot call function of unknown type [builtins fixtures/bool.pyi] [case testFunctionWithNameUnderscore] diff --git a/test-data/unit/check-inference-context.test b/test-data/unit/check-inference-context.test index afe6548df2d4..17ae6d9934b7 100644 --- a/test-data/unit/check-inference-context.test +++ b/test-data/unit/check-inference-context.test @@ -701,7 +701,7 @@ class A: pass class B(A): pass class C(A): pass def f(func: Callable[[T], S], *z: T, r: Optional[S] = None) -> S: pass -reveal_type(f(lambda x: 0 if isinstance(x, B) else 1)) # N: Revealed type is "builtins.int" +reveal_type(f(lambda x: 0 if isinstance(x, B) else 1)) # N: Revealed type is "Union[Literal[0]?, Literal[1]?]" f(lambda x: 0 if isinstance(x, B) else 1, A())() # E: "int" not callable f(lambda x: x if isinstance(x, B) else B(), A(), r=B())() # E: "B" not callable f( @@ -1391,7 +1391,7 @@ from typing import Union, List, Any def f(x: Union[List[str], Any]) -> None: a = x if x else [] - reveal_type(a) # N: Revealed type is "Union[builtins.list[Union[builtins.str, Any]], builtins.list[builtins.str], Any]" + reveal_type(a) # N: Revealed type is "Union[builtins.list[builtins.str], Any, builtins.list[Union[builtins.str, Any]]]" [builtins fixtures/list.pyi] [case testConditionalExpressionWithEmptyIteableAndUnionWithAny] @@ -1399,7 +1399,7 @@ from typing import Union, Iterable, Any def f(x: Union[Iterable[str], Any]) -> None: a = x if x else [] - reveal_type(a) # N: Revealed type is "Union[builtins.list[Union[builtins.str, Any]], typing.Iterable[builtins.str], Any]" + reveal_type(a) # N: Revealed type is "Union[typing.Iterable[builtins.str], Any, builtins.list[Union[builtins.str, Any]]]" [builtins fixtures/list.pyi] [case testInferMultipleAnyUnionCovariant] diff --git a/test-data/unit/check-inference.test b/test-data/unit/check-inference.test index fcd03f8efe01..0dbefbc774a3 100644 --- a/test-data/unit/check-inference.test +++ b/test-data/unit/check-inference.test @@ -1438,18 +1438,22 @@ class Wrapper: def f(cond: bool) -> Any: f = Wrapper if cond else lambda x: x - reveal_type(f) # N: Revealed type is "def (x: Any) -> Any" + reveal_type(f) # N: Revealed type is "Union[def (x: Any) -> __main__.Wrapper, def (x: Any) -> Any]" return f(3) def g(cond: bool) -> Any: f = lambda x: x if cond else Wrapper - reveal_type(f) # N: Revealed type is "def (x: Any) -> Any" + reveal_type(f) # N: Revealed type is "def (x: Any) -> Union[Any, def (x: Any) -> __main__.Wrapper]" + return f(3) + +def h(cond: bool) -> Any: + f = (lambda x: x) if cond else Wrapper + reveal_type(f) # N: Revealed type is "Union[def (x: Any) -> Any, def (x: Any) -> __main__.Wrapper]" return f(3) -- Boolean operators -- ----------------- - [case testOrOperationWithGenericOperands] from typing import List a: List[A] diff --git a/test-data/unit/check-optional.test b/test-data/unit/check-optional.test index 70f3c4486e14..f80aa5115bc3 100644 --- a/test-data/unit/check-optional.test +++ b/test-data/unit/check-optional.test @@ -395,7 +395,7 @@ def lookup_field(name, obj): attr = None [case testTernaryWithNone] -reveal_type(None if bool() else 0) # N: Revealed type is "Union[Literal[0]?, None]" +reveal_type(None if bool() else 0) # N: Revealed type is "Union[None, Literal[0]?]" [builtins fixtures/bool.pyi] [case testListWithNone] diff --git a/test-data/unit/check-tuples.test b/test-data/unit/check-tuples.test index bf36977b56e3..972bccf8c24b 100644 --- a/test-data/unit/check-tuples.test +++ b/test-data/unit/check-tuples.test @@ -1228,68 +1228,76 @@ x, y = g(z) # E: Argument 1 to "g" has incompatible type "int"; expected "Tuple[ [out] [case testFixedTupleJoinVarTuple] -from typing import Tuple +from typing import Tuple, TypeVar class A: pass class B(A): pass fixtup: Tuple[B, B] +T = TypeVar("T") +def join(x: T, y: T) -> T: ... + vartup_b: Tuple[B, ...] -reveal_type(fixtup if int() else vartup_b) # N: Revealed type is "builtins.tuple[__main__.B, ...]" -reveal_type(vartup_b if int() else fixtup) # N: Revealed type is "builtins.tuple[__main__.B, ...]" +reveal_type(join(fixtup, vartup_b)) # N: Revealed type is "builtins.tuple[__main__.B, ...]" +reveal_type(join(vartup_b, fixtup)) # N: Revealed type is "builtins.tuple[__main__.B, ...]" vartup_a: Tuple[A, ...] -reveal_type(fixtup if int() else vartup_a) # N: Revealed type is "builtins.tuple[__main__.A, ...]" -reveal_type(vartup_a if int() else fixtup) # N: Revealed type is "builtins.tuple[__main__.A, ...]" - +reveal_type(join(fixtup, vartup_a)) # N: Revealed type is "builtins.tuple[__main__.A, ...]" +reveal_type(join(vartup_a, fixtup)) # N: Revealed type is "builtins.tuple[__main__.A, ...]" [builtins fixtures/tuple.pyi] [out] [case testFixedTupleJoinList] -from typing import Tuple, List +from typing import Tuple, List, TypeVar class A: pass class B(A): pass fixtup: Tuple[B, B] +T = TypeVar("T") +def join(x: T, y: T) -> T: ... + lst_b: List[B] -reveal_type(fixtup if int() else lst_b) # N: Revealed type is "typing.Sequence[__main__.B]" -reveal_type(lst_b if int() else fixtup) # N: Revealed type is "typing.Sequence[__main__.B]" +reveal_type(join(fixtup, lst_b)) # N: Revealed type is "typing.Sequence[__main__.B]" +reveal_type(join(lst_b, fixtup)) # N: Revealed type is "typing.Sequence[__main__.B]" lst_a: List[A] -reveal_type(fixtup if int() else lst_a) # N: Revealed type is "typing.Sequence[__main__.A]" -reveal_type(lst_a if int() else fixtup) # N: Revealed type is "typing.Sequence[__main__.A]" +reveal_type(join(fixtup, lst_a)) # N: Revealed type is "typing.Sequence[__main__.A]" +reveal_type(join(lst_a, fixtup)) # N: Revealed type is "typing.Sequence[__main__.A]" [builtins fixtures/tuple.pyi] [out] [case testEmptyTupleJoin] -from typing import Tuple, List +from typing import Tuple, List, TypeVar class A: pass empty = () +T = TypeVar("T") +def join(x: T, y: T) -> T: ... + fixtup: Tuple[A] -reveal_type(fixtup if int() else empty) # N: Revealed type is "builtins.tuple[__main__.A, ...]" -reveal_type(empty if int() else fixtup) # N: Revealed type is "builtins.tuple[__main__.A, ...]" +reveal_type(join(fixtup, empty)) # N: Revealed type is "builtins.tuple[__main__.A, ...]" +reveal_type(join(empty, fixtup)) # N: Revealed type is "builtins.tuple[__main__.A, ...]" vartup: Tuple[A, ...] -reveal_type(empty if int() else vartup) # N: Revealed type is "builtins.tuple[__main__.A, ...]" -reveal_type(vartup if int() else empty) # N: Revealed type is "builtins.tuple[__main__.A, ...]" +reveal_type(join(vartup, empty)) # N: Revealed type is "builtins.tuple[__main__.A, ...]" +reveal_type(join(empty, vartup)) # N: Revealed type is "builtins.tuple[__main__.A, ...]" lst: List[A] -reveal_type(empty if int() else lst) # N: Revealed type is "typing.Sequence[__main__.A]" -reveal_type(lst if int() else empty) # N: Revealed type is "typing.Sequence[__main__.A]" +reveal_type(join(empty, lst)) # N: Revealed type is "typing.Sequence[__main__.A]" +reveal_type(join(lst, empty)) # N: Revealed type is "typing.Sequence[__main__.A]" [builtins fixtures/tuple.pyi] [out] [case testTupleSubclassJoin] -from typing import Tuple, NamedTuple +from typing import Tuple, NamedTuple, TypeVar class NTup(NamedTuple): a: bool @@ -1302,32 +1310,38 @@ ntup: NTup subtup: SubTuple vartup: SubVarTuple -reveal_type(ntup if int() else vartup) # N: Revealed type is "builtins.tuple[builtins.int, ...]" -reveal_type(subtup if int() else vartup) # N: Revealed type is "builtins.tuple[builtins.int, ...]" +T = TypeVar("T") +def join(x: T, y: T) -> T: ... + +reveal_type(join(ntup, vartup)) # N: Revealed type is "builtins.tuple[builtins.int, ...]" +reveal_type(join(subtup, vartup)) # N: Revealed type is "builtins.tuple[builtins.int, ...]" [builtins fixtures/tuple.pyi] [out] [case testTupleJoinIrregular] -from typing import Tuple +from typing import Tuple, TypeVar tup1: Tuple[bool, int] tup2: Tuple[bool] -reveal_type(tup1 if int() else tup2) # N: Revealed type is "builtins.tuple[builtins.int, ...]" -reveal_type(tup2 if int() else tup1) # N: Revealed type is "builtins.tuple[builtins.int, ...]" +T = TypeVar("T") +def join(x: T, y: T) -> T: ... + +reveal_type(join(tup1, tup2)) # N: Revealed type is "builtins.tuple[builtins.int, ...]" +reveal_type(join(tup2, tup1)) # N: Revealed type is "builtins.tuple[builtins.int, ...]" -reveal_type(tup1 if int() else ()) # N: Revealed type is "builtins.tuple[builtins.int, ...]" -reveal_type(() if int() else tup1) # N: Revealed type is "builtins.tuple[builtins.int, ...]" +reveal_type(join(tup1, ())) # N: Revealed type is "builtins.tuple[builtins.int, ...]" +reveal_type(join((), tup1)) # N: Revealed type is "builtins.tuple[builtins.int, ...]" -reveal_type(tup2 if int() else ()) # N: Revealed type is "builtins.tuple[builtins.bool, ...]" -reveal_type(() if int() else tup2) # N: Revealed type is "builtins.tuple[builtins.bool, ...]" +reveal_type(join(tup2, ())) # N: Revealed type is "builtins.tuple[builtins.bool, ...]" +reveal_type(join((), tup2)) # N: Revealed type is "builtins.tuple[builtins.bool, ...]" [builtins fixtures/tuple.pyi] [out] [case testTupleSubclassJoinIrregular] -from typing import Tuple, NamedTuple +from typing import Tuple, NamedTuple, TypeVar class NTup1(NamedTuple): a: bool @@ -1342,14 +1356,17 @@ tup1: NTup1 tup2: NTup2 subtup: SubTuple -reveal_type(tup1 if int() else tup2) # N: Revealed type is "builtins.tuple[builtins.bool, ...]" -reveal_type(tup2 if int() else tup1) # N: Revealed type is "builtins.tuple[builtins.bool, ...]" +T = TypeVar("T") +def join(x: T, y: T) -> T: ... + +reveal_type(join(tup1, tup2)) # N: Revealed type is "builtins.tuple[builtins.bool, ...]" +reveal_type(join(tup2, tup1)) # N: Revealed type is "builtins.tuple[builtins.bool, ...]" -reveal_type(tup1 if int() else subtup) # N: Revealed type is "builtins.tuple[builtins.int, ...]" -reveal_type(subtup if int() else tup1) # N: Revealed type is "builtins.tuple[builtins.int, ...]" +reveal_type(join(tup1, subtup)) # N: Revealed type is "builtins.tuple[builtins.int, ...]" +reveal_type(join(subtup, tup1)) # N: Revealed type is "builtins.tuple[builtins.int, ...]" -reveal_type(tup2 if int() else subtup) # N: Revealed type is "builtins.tuple[builtins.int, ...]" -reveal_type(subtup if int() else tup2) # N: Revealed type is "builtins.tuple[builtins.int, ...]" +reveal_type(join(tup2, subtup)) # N: Revealed type is "builtins.tuple[builtins.int, ...]" +reveal_type(join(subtup, tup2)) # N: Revealed type is "builtins.tuple[builtins.int, ...]" [builtins fixtures/tuple.pyi] [out]