Alex Waygood bc6ea68733 [ty] Add precise iteration and unpacking inference for string literals and bytes literals (#20023) ... ## Summary Previously we held off from doing this because we weren't sure that it was worth the added complexity cost. But our code has changed in the months since we made that initial decision, and I think the structure of the code is such that it no longer really leads to much added complexity to add precise inference when unpacking a string literal or a bytes literal. The improved inference we gain from this has real benefits to users (see the mypy_primer report), and this PR doesn't appear to have a performance impact. ## Test plan mdtests		2025-08-22 19:33:08 +01:00
..
annotations	[ty] Track when type variables are inferable or not (#19786)	2025-08-16 18:25:03 -04:00
assignment	[ty] Return Option<TupleType> from infer_tuple_type_expression (#19735)	2025-08-04 13:48:19 +01:00
binary	[ty] Remove special casing for string-literal-in-tuple __contains__ (#19642)	2025-07-31 11:28:03 +01:00
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
call	[ty] Avoid unnecessary argument type expansion (#19999)	2025-08-21 06:13:11 +00:00
class	[ty] Remove use of ClassBase::try_from_type from super() machinery (#19902)	2025-08-14 22:14:31 +01:00
comparison	[ty] Enum literal types (#19328)	2025-07-15 21:31:53 +02:00
comprehensions	[ty] Async for loops and async iterables (#19634)	2025-07-30 17:40:24 +02:00
conditional	[ty] Support as-patterns in reachability analysis (#19728)	2025-08-04 20:13:50 +02:00
dataclasses	[ty] correctly ignore field specifiers when not specified (#20002)	2025-08-20 11:33:23 -07:00
declaration	[ty] Format conflicting types as an enumeration (#18956)	2025-06-26 14:29:33 +02:00
diagnostics	[ty] Improve diagnostics for bad calls to functions (#20022)	2025-08-21 22:00:44 +01:00
directives	[ty] Exhaustiveness checking & reachability for match statements (#19508)	2025-07-23 22:45:45 +02:00
doc
exception	[ty] Use separate Rust types for bound and unbound type variables (#19796)	2025-08-11 15:29:58 -04:00
expression	[ty] Support async/await, async with and yield from (#19595)	2025-07-30 11:51:21 +02:00
function	[ty] Short circuit ReachabilityConstraints::analyze_single for dynamic types (#19867)	2025-08-11 21:58:34 +02:00
generics	[ty] Perform assignability etc checks using new Constraints trait (#19838)	2025-08-21 09:30:09 -04:00
ide_support	[ty] Fix attribute access on TypedDicts (#19758)	2025-08-05 13:59:10 +02:00
import	[ty] Add link for namespaces being partial (#20015)	2025-08-20 21:28:57 -07:00
literal
loops	[ty] Add precise iteration and unpacking inference for string literals and bytes literals (#20023)	2025-08-22 19:33:08 +01:00
narrow	[ty] linear variance inference for PEP-695 type parameters (#18713)	2025-08-19 17:54:09 -07:00
regression
scopes	[ty] fix deferred name loading in PEP695 generic classes/functions (#19888)	2025-08-13 15:51:59 -07:00
shadowing
snapshots	[ty] Sync vendored typeshed stubs (#20031)	2025-08-21 21:32:48 +00:00
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] Improve sys.version_info special casing (#19894)	2025-08-13 14:39:13 +01:00
suppressions	[ty] Consistent use of American english (in rules) (#19488)	2025-07-22 16:10:38 +02:00
type_compendium	[ty] Remove Type::Tuple (#19669)	2025-08-11 22:03:32 +01:00
type_of	[ty] Improve the Display for generic type[] types (#19667)	2025-07-31 19:45:01 +01:00
type_properties	[ty] Remove Type::Tuple (#19669)	2025-08-11 22:03:32 +01:00
type_qualifiers	[ty] Keep track of type qualifiers in stub declarations without right-hand side (#19756)	2025-08-05 12:07:05 +02:00
unary
with	[ty] Diagnostics for async context managers (#19704)	2025-08-05 07:41:37 -07:00
.mdformat.toml
async.md	[ty] Support async/await, async with and yield from (#19595)	2025-07-30 11:51:21 +02:00
attributes.md	[ty] Infer type[tuple[int, str]] as the meta-type of tuple[int, str] (#19741)	2025-08-04 13:10:47 +00:00
cycle.md	[ty] Add cycle handling for unpacking targets (#18078)	2025-05-13 21:27:48 +00:00
decorators.md
del.md	[ty] Support __setitem__ and improve __getitem__ related diagnostics (#19578)	2025-08-01 09:23:27 +02:00
deprecated.md	[ty] Consistent use of American english (in rules) (#19488)	2025-07-22 16:10:38 +02:00
descriptor_protocol.md	[ty] Fix descriptor lookups for most types that overlap with None (#19120)	2025-07-05 19:34:23 +01:00
enums.md	[ty] Infer the correct type of Enum __eq__ and __ne__ comparisions (#19666)	2025-08-18 19:45:44 +02:00
exhaustiveness_checking.md	[ty] Add precise iteration and unpacking inference for string literals and bytes literals (#20023)	2025-08-22 19:33:08 +01:00
final.md
instance_layout_conflict.md	[ty] Remove special casing for tuple addition (#19636)	2025-07-30 16:25:42 +00:00
intersection_types.md	[ty] Expansion of enums into unions of literals (#19382)	2025-07-21 19:37:55 +02:00
invalid_syntax.md
known_constants.md
mdtest_config.md
mdtest_custom_typeshed.md	[ty] Remove Type::Tuple (#19669)	2025-08-11 22:03:32 +01:00
metaclass.md
mro.md	[ty] Track different uses of legacy typevars, including context when rendering typevars (#19604)	2025-08-01 12:20:32 -04:00
named_tuple.md	[ty] Detect NamedTuple classes where fields without default values follow fields with default values (#19945)	2025-08-19 08:56:08 +00:00
overloads.md	[ty] Track different uses of legacy typevars, including context when rendering typevars (#19604)	2025-08-01 12:20:32 -04:00
pep695_type_aliases.md	[ty] fix unpacking a type alias with detailed tuple spec (#19981)	2025-08-18 17:54:05 -07:00
properties.md
protocols.md	[ty] Strict validation of protocol members (#17750)	2025-08-19 22:45:41 +00:00
public_types.md	[ty] improve lazy scope place lookup (#19321)	2025-07-25 07:11:11 +00:00
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] improve lazy scope place lookup (#19321)	2025-07-25 07:11:11 +00:00
ty_extensions.md	[ty] Rename type_api => ty_extensions (#19523)	2025-07-24 08:24:26 +00:00
typed_dict.md	[ty] Validate writes to TypedDict keys (#19782)	2025-08-06 15:19:13 -07:00
union_types.md	[ty] Expansion of enums into unions of literals (#19382)	2025-07-21 19:37:55 +02:00
unpacking.md	[ty] Add precise iteration and unpacking inference for string literals and bytes literals (#20023)	2025-08-22 19:33:08 +01:00
unreachable.md	[ty] improve lazy scope place lookup (#19321)	2025-07-25 07:11:11 +00:00