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Merge branch 'main' into dcreager/infer-function-calls
* main: [red-knot] Specialize `str.startswith` for string literals (#17351) [syntax-errors] `yield`, `yield from`, and `await` outside functions (#17298) [red-knot] Refresh diagnostics when changing related files (#17350) Add `Checker::import_from_typing` (#17340) Don't add chaperone space after escaped quote in triple quote (#17216) [red-knot] Silence errors in unreachable type annotations / class bases (#17342)
2 parents 0744540 + 47956db commit 701cfd1

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+1119
-264
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‎crates/red_knot_python_semantic/resources/mdtest/call/str_startswith.md

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# `str.startswith`
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We special-case `str.startswith` to allow inference of precise Boolean literal types, because those
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are used in [`sys.platform` checks].
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```py
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reveal_type("abc".startswith("")) # revealed: Literal[True]
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reveal_type("abc".startswith("a")) # revealed: Literal[True]
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reveal_type("abc".startswith("ab")) # revealed: Literal[True]
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reveal_type("abc".startswith("abc")) # revealed: Literal[True]
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reveal_type("abc".startswith("abcd")) # revealed: Literal[False]
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reveal_type("abc".startswith("bc")) # revealed: Literal[False]
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reveal_type("AbC".startswith("")) # revealed: Literal[True]
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reveal_type("AbC".startswith("A")) # revealed: Literal[True]
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reveal_type("AbC".startswith("Ab")) # revealed: Literal[True]
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reveal_type("AbC".startswith("AbC")) # revealed: Literal[True]
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reveal_type("AbC".startswith("a")) # revealed: Literal[False]
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reveal_type("AbC".startswith("aB")) # revealed: Literal[False]
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reveal_type("".startswith("")) # revealed: Literal[True]
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reveal_type("".startswith(" ")) # revealed: Literal[False]
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```
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Make sure that we fall back to `bool` for more complex cases:
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```py
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reveal_type("abc".startswith("b", 1)) # revealed: bool
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reveal_type("abc".startswith("bc", 1, 3)) # revealed: bool
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reveal_type("abc".startswith(("a", "x"))) # revealed: bool
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```
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And similiarly, we should still infer `bool` if the instance or the prefix are not string literals:
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```py
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from typing_extensions import LiteralString
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def _(string_instance: str, literalstring: LiteralString):
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reveal_type(string_instance.startswith("a")) # revealed: bool
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reveal_type(literalstring.startswith("a")) # revealed: bool
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reveal_type("a".startswith(string_instance)) # revealed: bool
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reveal_type("a".startswith(literalstring)) # revealed: bool
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```
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[`sys.platform` checks]: https://docs.python.org/3/library/sys.html#sys.platform

‎crates/red_knot_python_semantic/resources/mdtest/sys_platform.md

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@@ -31,13 +31,13 @@ reveal_type(sys.platform) # revealed: Literal["linux"]
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## Testing for a specific platform
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### Exact comparison
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```toml
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[environment]
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python-platform = "freebsd8"
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```
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### Exact comparison
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```py
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import sys
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@@ -48,11 +48,11 @@ reveal_type(sys.platform == "linux") # revealed: Literal[False]
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### Substring comparison
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It is [recommended](https://docs.python.org/3/library/sys.html#sys.platform) to use
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`sys.platform.startswith(...)` for platform checks. This is not yet supported in type inference:
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`sys.platform.startswith(...)` for platform checks:
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```py
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import sys
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reveal_type(sys.platform.startswith("freebsd")) # revealed: bool
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reveal_type(sys.platform.startswith("linux")) # revealed: bool
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reveal_type(sys.platform.startswith("freebsd")) # revealed: Literal[True]
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reveal_type(sys.platform.startswith("linux")) # revealed: Literal[False]
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```

‎crates/red_knot_python_semantic/resources/mdtest/unreachable.md

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@@ -447,15 +447,16 @@ We should not show any diagnostics in type annotations inside unreachable sectio
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```py
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def _():
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class C: ...
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class C:
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class Inner: ...
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return
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# TODO
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# error: [invalid-type-form] "Variable of type `Never` is not allowed in a type expression"
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c: C = C()
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c1: C = C()
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c2: C.Inner = C.Inner()
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c3: tuple[C, C] = (C(), C())
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c4: tuple[C.Inner, C.Inner] = (C.Inner(), C.Inner())
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# TODO
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# error: [invalid-base] "Invalid class base with type `Never` (all bases must be a class, `Any`, `Unknown` or `Todo`)"
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class Sub(C): ...
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```
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‎crates/red_knot_python_semantic/src/types.rs

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@@ -2508,6 +2508,10 @@ impl<'db> Type<'db> {
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Type::MethodWrapper(MethodWrapperKind::PropertyDunderSet(property)),
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)
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.into(),
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Type::StringLiteral(literal) if name == "startswith" => Symbol::bound(
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Type::MethodWrapper(MethodWrapperKind::StrStartswith(literal)),
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)
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.into(),
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Type::ClassLiteral(class)
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if name == "__get__" && class.is_known(db, KnownClass::FunctionType) =>
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))
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}
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Type::MethodWrapper(MethodWrapperKind::StrStartswith(_)) => {
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Signatures::single(CallableSignature::single(
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self,
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Signature::new(
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Parameters::new([
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Parameter::positional_only(Some(Name::new_static("prefix")))
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.with_annotated_type(UnionType::from_elements(
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db,
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[
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KnownClass::Str.to_instance(db),
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// TODO: tuple[str, ...]
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KnownClass::Tuple.to_instance(db),
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],
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)),
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Parameter::positional_only(Some(Name::new_static("start")))
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// TODO: SupportsIndex | None
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.with_annotated_type(Type::object(db))
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.with_default_type(Type::none(db)),
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Parameter::positional_only(Some(Name::new_static("end")))
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// TODO: SupportsIndex | None
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.with_annotated_type(Type::object(db))
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.with_default_type(Type::none(db)),
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]),
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Some(KnownClass::Bool.to_instance(db)),
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),
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))
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}
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Type::FunctionLiteral(function_type) => match function_type.known(db) {
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Some(
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KnownFunction::IsEquivalentTo
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| Type::AlwaysTruthy
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| Type::AlwaysFalsy
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| Type::WrapperDescriptor(_)
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| Type::MethodWrapper(MethodWrapperKind::StrStartswith(_))
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| Type::ModuleLiteral(_)
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// A non-generic class never needs to be specialized. A generic class is specialized
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// explicitly (via a subscript expression) or implicitly (via a call), and not because
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}
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impl<'db> InvalidTypeExpressionError<'db> {
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fn into_fallback_type(self, context: &InferContext, node: &ast::Expr) -> Type<'db> {
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fn into_fallback_type(
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self,
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context: &InferContext,
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node: &ast::Expr,
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is_reachable: bool,
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) -> Type<'db> {
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let InvalidTypeExpressionError {
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fallback_type,
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invalid_expressions,
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} = self;
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for error in invalid_expressions {
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context.report_lint_old(
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&INVALID_TYPE_FORM,
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node,
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format_args!("{}", error.reason(context.db())),
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);
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if is_reachable {
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for error in invalid_expressions {
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context.report_lint_old(
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&INVALID_TYPE_FORM,
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node,
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format_args!("{}", error.reason(context.db())),
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);
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}
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}
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fallback_type
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}
@@ -6219,6 +6259,8 @@ pub enum MethodWrapperKind<'db> {
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PropertyDunderGet(PropertyInstanceType<'db>),
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/// Method wrapper for `some_property.__set__`
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PropertyDunderSet(PropertyInstanceType<'db>),
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/// Method wrapper for `str.startswith`
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StrStartswith(StringLiteralType<'db>),
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}
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/// Represents a specific instance of `types.WrapperDescriptorType`

‎crates/red_knot_python_semantic/src/types/call/bind.rs

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@@ -403,6 +403,16 @@ impl<'db> Bindings<'db> {
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}
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}
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Type::MethodWrapper(MethodWrapperKind::StrStartswith(literal)) => {
407+
if let [Some(Type::StringLiteral(prefix)), None, None] =
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overload.parameter_types()
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{
410+
overload.set_return_type(Type::BooleanLiteral(
411+
literal.value(db).starts_with(&**prefix.value(db)),
412+
));
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}
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}
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Type::BoundMethod(bound_method)
407417
if bound_method.self_instance(db).is_property_instance() =>
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{

‎crates/red_knot_python_semantic/src/types/display.rs

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Type::MethodWrapper(MethodWrapperKind::PropertyDunderSet(_)) => {
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write!(f, "<method-wrapper `__set__` of `property` object>",)
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}
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Type::MethodWrapper(MethodWrapperKind::StrStartswith(_)) => {
149+
write!(f, "<method-wrapper `startswith` of `str` object>",)
150+
}
148151
Type::WrapperDescriptor(kind) => {
149152
let (method, object) = match kind {
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WrapperDescriptorKind::FunctionTypeDunderGet => ("__get__", "function"),

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