Drop support for --python-version 3.8 (#19157)

Drop last remaining support for Python 3.8. Support for running with 3.8
was removed in #17492 already. This PR removes the option to use 3.8
with `--python-version` since the type stubs only support 3.9+, see
#18930.

Author: cdce8p

mypy/defaults.py

@@ -10,7 +10,7 @@
 
 # Earliest Python 3.x version supported via --python-version 3.x. To run
 # mypy, at least version PYTHON3_VERSION is needed.
-PYTHON3_VERSION_MIN: Final = (3, 8)  # Keep in sync with typeshed's python support
+PYTHON3_VERSION_MIN: Final = (3, 9)  # Keep in sync with typeshed's python support
 
 CACHE_DIR: Final = ".mypy_cache"
 

mypy/modulefinder.py

@@ -995,6 +995,6 @@ def parse_version(version: str) -> tuple[int, int]:
 
 def typeshed_py_version(options: Options) -> tuple[int, int]:
     """Return Python version used for checking whether module supports typeshed."""
-    # Typeshed no longer covers Python 3.x versions before 3.8, so 3.8 is
+    # Typeshed no longer covers Python 3.x versions before 3.9, so 3.9 is
     # the earliest we can support.
-    return max(options.python_version, (3, 8))
+    return max(options.python_version, (3, 9))

mypy/nodes.py

@@ -148,18 +148,6 @@ def set_line(
     "builtins.frozenset": "typing.FrozenSet",
 }
 
-_nongen_builtins: Final = {"builtins.tuple": "typing.Tuple", "builtins.enumerate": ""}
-_nongen_builtins.update((name, alias) for alias, name in type_aliases.items())
-# Drop OrderedDict from this for backward compatibility
-del _nongen_builtins["collections.OrderedDict"]
-# HACK: consequence of hackily treating LiteralString as an alias for str
-del _nongen_builtins["builtins.str"]
-
-
-def get_nongen_builtins(python_version: tuple[int, int]) -> dict[str, str]:
-    # After 3.9 with pep585 generic builtins are allowed
-    return _nongen_builtins if python_version < (3, 9) else {}
-
 
 RUNTIME_PROTOCOL_DECOS: Final = (
     "typing.runtime_checkable",

mypy/semanal.py

@@ -184,7 +184,6 @@
     YieldExpr,
     YieldFromExpr,
     get_member_expr_fullname,
-    get_nongen_builtins,
     implicit_module_attrs,
     is_final_node,
     type_aliases,
@@ -247,7 +246,6 @@
     find_self_type,
     fix_instance,
     has_any_from_unimported_type,
-    no_subscript_builtin_alias,
     type_constructors,
     validate_instance,
 )
@@ -5996,30 +5994,6 @@ def analyze_type_application(self, expr: IndexExpr) -> None:
         expr.analyzed = TypeApplication(base, types)
         expr.analyzed.line = expr.line
         expr.analyzed.column = expr.column
-        # Types list, dict, set are not subscriptable, prohibit this if
-        # subscripted either via type alias...
-        if isinstance(base, RefExpr) and isinstance(base.node, TypeAlias):
-            alias = base.node
-            target = get_proper_type(alias.target)
-            if isinstance(target, Instance):
-                name = target.type.fullname
-                if (
-                    alias.no_args
-                    and name  # this avoids bogus errors for already reported aliases
-                    in get_nongen_builtins(self.options.python_version)
-                    and not self.is_stub_file
-                    and not alias.normalized
-                ):
-                    self.fail(no_subscript_builtin_alias(name, propose_alt=False), expr)
-        # ...or directly.
-        else:
-            n = self.lookup_type_node(base)
-            if (
-                n
-                and n.fullname in get_nongen_builtins(self.options.python_version)
-                and not self.is_stub_file
-            ):
-                self.fail(no_subscript_builtin_alias(n.fullname, propose_alt=False), expr)
 
     def analyze_type_application_args(self, expr: IndexExpr) -> list[Type] | None:
         """Analyze type arguments (index) in a type application.

mypy/typeanal.py

@@ -47,7 +47,6 @@
     Var,
     check_arg_kinds,
     check_arg_names,
-    get_nongen_builtins,
 )
 from mypy.options import INLINE_TYPEDDICT, Options
 from mypy.plugin import AnalyzeTypeContext, Plugin, TypeAnalyzerPluginInterface
@@ -136,12 +135,6 @@
     "mypy_extensions.KwArg": ARG_STAR2,
 }
 
-GENERIC_STUB_NOT_AT_RUNTIME_TYPES: Final = {
-    "queue.Queue",
-    "builtins._PathLike",
-    "asyncio.futures.Future",
-}
-
 SELF_TYPE_NAMES: Final = {"typing.Self", "typing_extensions.Self"}
 
 
@@ -186,17 +179,6 @@ def analyze_type_alias(
     return res, analyzer.aliases_used
 
 
-def no_subscript_builtin_alias(name: str, propose_alt: bool = True) -> str:
-    class_name = name.split(".")[-1]
-    msg = f'"{class_name}" is not subscriptable'
-    # This should never be called if the python_version is 3.9 or newer
-    nongen_builtins = get_nongen_builtins((3, 8))
-    replacement = nongen_builtins[name]
-    if replacement and propose_alt:
-        msg += f', use "{replacement}" instead'
-    return msg
-
-
 class TypeAnalyser(SyntheticTypeVisitor[Type], TypeAnalyzerPluginInterface):
     """Semantic analyzer for types.
 
@@ -360,14 +342,6 @@ def visit_unbound_type_nonoptional(self, t: UnboundType, defining_literal: bool)
             hook = self.plugin.get_type_analyze_hook(fullname)
             if hook is not None:
                 return hook(AnalyzeTypeContext(t, t, self))
-            if (
-                fullname in get_nongen_builtins(self.options.python_version)
-                and t.args
-                and not self.always_allow_new_syntax
-            ):
-                self.fail(
-                    no_subscript_builtin_alias(fullname, propose_alt=not self.defining_alias), t
-                )
             tvar_def = self.tvar_scope.get_binding(sym)
             if isinstance(sym.node, ParamSpecExpr):
                 if tvar_def is None:
@@ -2033,44 +2007,14 @@ def get_omitted_any(
     unexpanded_type: Type | None = None,
 ) -> AnyType:
     if disallow_any:
-        nongen_builtins = get_nongen_builtins(options.python_version)
-        if fullname in nongen_builtins:
-            typ = orig_type
-            # We use a dedicated error message for builtin generics (as the most common case).
-            alternative = nongen_builtins[fullname]
-            fail(
-                message_registry.IMPLICIT_GENERIC_ANY_BUILTIN.format(alternative),
-                typ,
-                code=codes.TYPE_ARG,
-            )
-        else:
-            typ = unexpanded_type or orig_type
-            type_str = typ.name if isinstance(typ, UnboundType) else format_type_bare(typ, options)
+        typ = unexpanded_type or orig_type
+        type_str = typ.name if isinstance(typ, UnboundType) else format_type_bare(typ, options)
 
-            fail(
-                message_registry.BARE_GENERIC.format(quote_type_string(type_str)),
-                typ,
-                code=codes.TYPE_ARG,
-            )
-            base_type = get_proper_type(orig_type)
-            base_fullname = (
-                base_type.type.fullname if isinstance(base_type, Instance) else fullname
-            )
-            # Ideally, we'd check whether the type is quoted or `from __future__ annotations`
-            # is set before issuing this note
-            if (
-                options.python_version < (3, 9)
-                and base_fullname in GENERIC_STUB_NOT_AT_RUNTIME_TYPES
-            ):
-                # Recommend `from __future__ import annotations` or to put type in quotes
-                # (string literal escaping) for classes not generic at runtime
-                note(
-                    "Subscripting classes that are not generic at runtime may require "
-                    "escaping, see https://mypy.readthedocs.io/en/stable/runtime_troubles.html"
-                    "#not-generic-runtime",
-                    typ,
-                    code=codes.TYPE_ARG,
-                )
+        fail(
+            message_registry.BARE_GENERIC.format(quote_type_string(type_str)),
+            typ,
+            code=codes.TYPE_ARG,
+        )
 
         any_type = AnyType(TypeOfAny.from_error, line=typ.line, column=typ.column)
     else:

mypyc/test-data/run-misc.test

@@ -984,15 +984,6 @@ elif sys.version_info[:2] == (3, 10):
 elif sys.version_info[:2] == (3, 9):
     def version() -> int:
         return 9
-elif sys.version_info[:2] == (3, 8):
-    def version() -> int:
-        return 8
-elif sys.version_info[:2] == (3, 7):
-    def version() -> int:
-        return 7
-elif sys.version_info[:2] == (3, 6):
-    def version() -> int:
-        return 6
 else:
     raise Exception("we don't support this version yet!")
 

mypyc/test/testutil.py

@@ -111,7 +111,7 @@ def build_ir_for_single_file2(
     options.hide_error_codes = True
     options.use_builtins_fixtures = True
     options.strict_optional = True
-    options.python_version = compiler_options.python_version or (3, 8)
+    options.python_version = compiler_options.python_version or (3, 9)
     options.export_types = True
     options.preserve_asts = True
     options.allow_empty_bodies = True

test-data/unit/check-annotated.test

@@ -144,15 +144,7 @@ def f4(a: Annotated[T, "metadata"]):
 reveal_type(f4)  # N: Revealed type is "def [T] (a: T`-1) -> Any"
 [builtins fixtures/tuple.pyi]
 
-[case testSliceAnnotated39]
-# flags: --python-version 3.9
-from typing_extensions import Annotated
-a: Annotated[int, 1:2]
-reveal_type(a)  # N: Revealed type is "builtins.int"
-[builtins fixtures/tuple.pyi]
-
-[case testSliceAnnotated38]
-# flags: --python-version 3.8
+[case testSliceAnnotated]
 from typing_extensions import Annotated
 a: Annotated[int, 1:2]
 reveal_type(a)  # N: Revealed type is "builtins.int"

test-data/unit/check-columns.test

@@ -261,10 +261,10 @@ class D(A):
                               # N:5:          def f(self) -> None
 
 [case testColumnMissingTypeParameters]
-# flags: --python-version 3.8 --disallow-any-generics
+# flags: --disallow-any-generics
 from typing import List, Callable
 def f(x: List) -> None: pass # E:10: Missing type parameters for generic type "List"
-def g(x: list) -> None: pass # E:10: Implicit generic "Any". Use "typing.List" and specify generic parameters
+def g(x: list) -> None: pass # E:10: Missing type parameters for generic type "List"
 if int():
     c: Callable # E:8: Missing type parameters for generic type "Callable"
 [builtins fixtures/list.pyi]

test-data/unit/check-dataclasses.test

@@ -1911,7 +1911,6 @@ SecondClass().SECOND_CONST = 42  # E: Cannot assign to final attribute "SECOND_C
 [builtins fixtures/dataclasses.pyi]
 
 [case testDataclassFieldsProtocol]
-# flags: --python-version 3.9
 from dataclasses import dataclass
 from typing import Any, Protocol