Abhijeet Prasad Bodas f4bd74ab6a [ty] Correctly handle calls to functions marked as returning Never / NoReturn (#18333) ... ## Summary `ty` does not understand that calls to functions which have been annotated as having a return type of `Never` / `NoReturn` are terminal. This PR fixes that, by adding new reachability constraints when call expressions are seen. If the call expression evaluates to `Never`, the code following it will be considered to be unreachable. Note that, for adding these constraints, we only consider call expressions at the statement level, and that too only inside function scopes. This is because otherwise, the number of such constraints becomes too high, and evaluating them later on during type inference results in a major performance degradation. Fixes https://github.com/astral-sh/ty/issues/180 ## Test Plan New mdtests. ## Ecosystem changes This PR removes the following false-positives: - "Function can implicitly return `None`, which is not assignable to ...". - "Name `foo` used when possibly not defind" - because the branch in which it is not defined has a `NoReturn` call, or when `foo` was imported in a `try`, and the except had a `NoReturn` call. --------- Co-authored-by: David Peter <mail@david-peter.de>		2025-07-04 11:52:52 -07:00
..
annotations	[ty] Emit error for invalid binary operations in type expressions (#18991)	2025-06-30 10:06:01 +02:00
assignment	[ty] Homogeneous and mixed tuples (#18600)	2025-06-20 18:23:54 -04:00
binary	[ty] Homogeneous and mixed tuples (#18600)	2025-06-20 18:23:54 -04:00
boolean	Revert "[ty] Better control flow for boolean expressions that are inside if (#18010)" (#18150)	2025-05-17 08:27:32 -04:00
boundness_declaredness	Update class literal display to use <class 'Foo'> style (#17889)	2025-05-06 20:11:25 -04:00
call	[ty] Allow declared-only class-level attributes to be accessed on the class (#19071)	2025-07-02 18:03:56 +02:00
class	Update class literal display to use <class 'Foo'> style (#17889)	2025-05-06 20:11:25 -04:00
comparison	[ty] Fix binary intersection comparison inference logic (#18266)	2025-05-23 12:55:17 +02:00
comprehensions
conditional	[ty] Improve disjointness inference for NominalInstanceTypes and SubclassOfTypes (#18864)	2025-06-24 20:27:37 +00:00
dataclasses	[ty] Restructure/move dataclass tests (#19117)	2025-07-03 10:36:14 +00:00
declaration	[ty] Format conflicting types as an enumeration (#18956)	2025-06-26 14:29:33 +02:00
diagnostics	[ty] Surface matched overload diagnostic directly (#18452)	2025-06-20 08:36:49 +05:30
directives	[ty] Correctly handle calls to functions marked as returning Never / NoReturn (#18333)	2025-07-04 11:52:52 -07:00
doc	ty_python_semantic: add union type context to function call type errors	2025-05-09 13:40:51 -04:00
exception	[ty] support del statement and deletion of except handler names (#18593)	2025-06-12 07:44:42 -07:00
expression	[ty] Make tuple instantiations sound (#18987)	2025-06-27 19:37:16 +01:00
function	[ty] Add diagnosis for function with no return statement but with return type annotation (#18359)	2025-05-29 23:17:18 +00:00
generics	[ty] Improve protocol member type checking and relation handling (#18847)	2025-06-29 10:46:33 +00:00
ide_support	[ty] Minor tweaks to "list all members" docs and tests (#18388)	2025-05-30 13:36:57 -04:00
import	[ty] don't allow first-party code to shadow stdlib types module (#19128)	2025-07-04 10:36:26 +00:00
literal	[ty] Understand classes that inherit from subscripted Protocol[] as generic (#17832)	2025-05-09 17:39:15 +01:00
loops
narrow	[ty] Eagerly simplify 'True' and 'False' constraints (#18998)	2025-06-30 13:11:52 +02:00
regression
scopes	[ty] Infer nonlocal types as unions of all reachable bindings (#18750)	2025-06-26 12:24:40 +02:00
shadowing
snapshots	[ty] Correctly handle calls to functions marked as returning Never / NoReturn (#18333)	2025-07-04 11:52:52 -07:00
stubs	[ty] Do not carry the generic context of Protocol or Generic in the ClassBase enum (#17989)	2025-05-22 21:37:03 -04:00
subscript	[ty] Fix false positives when subscripting an object inferred as having an Intersection type (#18920)	2025-06-24 18:39:02 +00:00
suppressions
type_compendium	[ty] Make tuple instantiations sound (#18987)	2025-06-27 19:37:16 +01:00
type_of	Update class literal display to use <class 'Foo'> style (#17889)	2025-05-06 20:11:25 -04:00
type_properties	[ty] Add subtyping between SubclassOf and CallableType (#19026)	2025-07-02 19:22:31 -07:00
type_qualifiers	[ty] Allow declared-only class-level attributes to be accessed on the class (#19071)	2025-07-02 18:03:56 +02:00
unary	Update class literal display to use <class 'Foo'> style (#17889)	2025-05-06 20:11:25 -04:00
with	[ty] Add hint if async context manager is used in non-async with statement (#18299)	2025-05-26 21:34:47 +02:00
.mdformat.toml
attributes.md	[ty] Allow declared-only class-level attributes to be accessed on the class (#19071)	2025-07-02 18:03:56 +02:00
cycle.md	[ty] Add cycle handling for unpacking targets (#18078)	2025-05-13 21:27:48 +00:00
decorators.md	ty_python_semantic: add union type context to function call type errors	2025-05-09 13:40:51 -04:00
del.md	[ty] support del statement and deletion of except handler names (#18593)	2025-06-12 07:44:42 -07:00
descriptor_protocol.md	[ty] Add support for @staticmethods (#18809)	2025-06-20 10:38:17 +02:00
final.md
instance_layout_conflict.md	[ty] Improve disjointness inference for NominalInstanceTypes and SubclassOfTypes (#18864)	2025-06-24 20:27:37 +00:00
intersection_types.md	[ty] eliminate is_fully_static (#18799)	2025-06-24 18:02:05 -07:00
invalid_syntax.md
known_constants.md
mdtest_config.md
mdtest_custom_typeshed.md	[ty] Fix duplicate diagnostics for unresolved module when an import from statement imports multiple members (#17886)	2025-05-06 12:37:10 +01:00
metaclass.md	Update class literal display to use <class 'Foo'> style (#17889)	2025-05-06 20:11:25 -04:00
mro.md	[ty] Implement implicit inheritance from Generic[] for PEP-695 generic classes (#18283)	2025-05-26 20:40:16 +01:00
named_tuple.md	[ty] Add generic inference for dataclasses (#18443)	2025-06-03 09:59:43 -07:00
overloads.md	[ty] Add support for @staticmethods (#18809)	2025-06-20 10:38:17 +02:00
pep695_type_aliases.md	[ty] Support typing.TypeAliasType (#18156)	2025-05-19 16:36:49 +02:00
properties.md	ty_python_semantic: add union type context to function call type errors	2025-05-09 13:40:51 -04:00
protocols.md	[ty] detect cycles in Type::is_disjoint_from (#19139)	2025-07-04 06:31:44 -07:00
public_types.md	[ty] Infer nonlocal types as unions of all reachable bindings (#18750)	2025-06-26 12:24:40 +02:00
statically_known_branches.md	[ty] Infer nonlocal types as unions of all reachable bindings (#18750)	2025-06-26 12:24:40 +02:00
sys_platform.md
sys_version_info.md
terminal_statements.md	[ty] Correctly handle calls to functions marked as returning Never / NoReturn (#18333)	2025-07-04 11:52:52 -07:00
type_api.md	[ty] eliminate is_fully_static (#18799)	2025-06-24 18:02:05 -07:00
typed_dict.md
union_types.md	[ty] eliminate is_fully_static (#18799)	2025-06-24 18:02:05 -07:00
unpacking.md	[ty] Support variable-length tuples in unpacking assignments (#18948)	2025-06-27 15:29:04 -04:00
unreachable.md	[ty] Infer nonlocal types as unions of all reachable bindings (#18750)	2025-06-26 12:24:40 +02:00