Treat non-future function annotations as required-at-runtime (#4028)

Author: charliermarsh

crates/ruff/resources/test/fixtures/flake8_type_checking/strict.py

@@ -1,3 +1,6 @@
+from __future__ import annotations
+
+
 def f():
     # Even in strict mode, this shouldn't rase an error, since `pkg` is used at runtime,
     # and implicitly imports `pkg.bar`.

crates/ruff/src/checkers/ast/mod.rs

@@ -598,14 +598,9 @@ where
                     self.visit_expr(expr);
                 }
 
-                // If we're in a class or module scope, then the annotation needs to be
-                // available at runtime.
-                // See: https://docs.python.org/3/reference/simple_stmts.html#annotated-assignment-statements
-                let runtime_annotation = !self.ctx.annotations_future_enabled
-                    && matches!(
-                        self.ctx.scope().kind,
-                        ScopeKind::Class(..) | ScopeKind::Module
-                    );
+                // Function annotations are always evaluated at runtime, unless future annotations
+                // are enabled.
+                let runtime_annotation = !self.ctx.annotations_future_enabled;
 
                 for arg in &args.posonlyargs {
                     if let Some(expr) = &arg.node.annotation {

crates/ruff/src/rules/flake8_type_checking/snapshots/ruff__rules__flake8_type_checking__tests__strict.snap

@@ -1,34 +1,34 @@
 ---
 source: crates/ruff/src/rules/flake8_type_checking/mod.rs
 ---
-strict.py:24:21: TCH002 Move third-party import `pkg.A` into a type-checking block
+strict.py:27:21: TCH002 Move third-party import `pkg.A` into a type-checking block
    |
-24 |     # In un-strict mode, this shouldn't rase an error, since `pkg` is used at runtime.
-25 |     import pkg
-26 |     from pkg import A
+27 |     # In un-strict mode, this shouldn't rase an error, since `pkg` is used at runtime.
+28 |     import pkg
+29 |     from pkg import A
    |                     ^ TCH002
-27 | 
-28 |     def test(value: A):
+30 | 
+31 |     def test(value: A):
    |
 
-strict.py:32:21: TCH002 Move third-party import `pkg.A` into a type-checking block
+strict.py:35:21: TCH002 Move third-party import `pkg.A` into a type-checking block
    |
-32 | def f():
-33 |     # In un-strict mode, this shouldn't rase an error, since `pkg` is used at runtime.
-34 |     from pkg import A, B
+35 | def f():
+36 |     # In un-strict mode, this shouldn't rase an error, since `pkg` is used at runtime.
+37 |     from pkg import A, B
    |                     ^ TCH002
-35 | 
-36 |     def test(value: A):
+38 | 
+39 |     def test(value: A):
    |
 
-strict.py:51:25: TCH002 Move third-party import `pkg.bar.A` into a type-checking block
+strict.py:54:25: TCH002 Move third-party import `pkg.bar.A` into a type-checking block
    |
-51 |     # In un-strict mode, this _should_ rase an error, since `pkg` is used at runtime.
-52 |     import pkg
-53 |     from pkg.bar import A
+54 |     # In un-strict mode, this _should_ rase an error, since `pkg` is used at runtime.
+55 |     import pkg
+56 |     from pkg.bar import A
    |                         ^ TCH002
-54 | 
-55 |     def test(value: A):
+57 | 
+58 |     def test(value: A):
    |
 
 

crates/ruff/src/rules/flake8_type_checking/snapshots/ruff__rules__flake8_type_checking__tests__typing-only-third-party-import_strict.py.snap

@@ -1,14 +1,14 @@
 ---
 source: crates/ruff/src/rules/flake8_type_checking/mod.rs
 ---
-strict.py:51:25: TCH002 Move third-party import `pkg.bar.A` into a type-checking block
+strict.py:54:25: TCH002 Move third-party import `pkg.bar.A` into a type-checking block
    |
-51 |     # In un-strict mode, this _should_ rase an error, since `pkg` is used at runtime.
-52 |     import pkg
-53 |     from pkg.bar import A
+54 |     # In un-strict mode, this _should_ rase an error, since `pkg` is used at runtime.
+55 |     import pkg
+56 |     from pkg.bar import A
    |                         ^ TCH002
-54 | 
-55 |     def test(value: A):
+57 | 
+58 |     def test(value: A):
    |