also fix most stringized references

crates/ruff_linter/resources/test/fixtures/flake8_pyi/PYI019_0.py

@@ -150,9 +150,14 @@ def n[S](cls: type[S], other: S) -> S:
         x: type[S] = type(other)
         return x()
 
-class StringizedReferencesAreTooComplicated:
+class StringizedReferencesCanBeFixed:
     def m[S](self: S) -> S:
-        x = cast("S", self)
+        x = cast("list[tuple[S, S]]", self)
+        return x
+
+class ButStrangeStringizedReferencesCannotBeFixed:
+    def m[_T](self: _T) -> _T:
+        x = cast('list[_\x54]', self)
         return x
 
 class DeletionsAreNotTouched:

crates/ruff_linter/src/rules/flake8_pyi/rules/custom_type_var_for_self.rs

@@ -204,7 +204,7 @@ pub(crate) fn custom_type_var_instead_of_self(
 
     let mut diagnostic = Diagnostic::new(
         CustomTypeVarForSelf {
-            typevar_name: custom_typevar.name(checker).to_string(),
+            typevar_name: custom_typevar.name(checker.source()).to_string(),
         },
         diagnostic_range,
     );
@@ -507,6 +507,7 @@ fn replace_custom_typevar_with_self(
 
     replace_typevar_usages_with_self(
         custom_typevar,
+        checker.source(),
         self_or_cls_annotation.range(),
         &self_symbol_binding,
         replace_references_range,
@@ -557,19 +558,23 @@ fn import_self(checker: &Checker, position: TextSize) -> Result<(Edit, String),
 /// This ensures that no edit in this series will overlap with other edits.
 fn replace_typevar_usages_with_self<'a>(
     typevar: TypeVar<'a>,
+    source: &'a str,
     self_or_cls_annotation_range: TextRange,
     self_symbol_binding: &'a str,
     editable_range: TextRange,
     semantic: &'a SemanticModel<'a>,
     edits: &mut Vec<Edit>,
 ) -> anyhow::Result<()> {
+    let tvar_name = typevar.name(source);
     for reference in typevar.references(semantic) {
-        if reference.in_string_type_definition() {
+        let reference_range = reference.range();
+        if &source[reference_range] != tvar_name {
             bail!(
-                "Cannot apply autofix where some references to the TypeVar are in string type definitions"
+                "Cannot autofix: feference in the source code (`{}`) is not equal to the typevar name (`{}`)",
+                &source[reference_range],
+                tvar_name
             );
         }
-        let reference_range = reference.range();
         if !editable_range.contains_range(reference_range) {
             continue;
         }
@@ -629,8 +634,8 @@ impl<'a> TypeVar<'a> {
         self.0.kind.is_type_param()
     }
 
-    fn name(self, checker: &'a Checker) -> &'a str {
-        self.0.name(checker.source())
+    fn name(self, source: &'a str) -> &'a str {
+        self.0.name(source)
     }
 
     fn references(

crates/ruff_linter/src/rules/flake8_pyi/snapshots/ruff_linter__rules__flake8_pyi__tests__PYI019_PYI019_0.py.snap

@@ -277,30 +277,40 @@ PYI019_0.py:149:41: PYI019 Use `Self` instead of custom TypeVar `S`
 
 PYI019_0.py:154:26: PYI019 Use `Self` instead of custom TypeVar `S`
     |
-153 | class StringizedReferencesAreTooComplicated:
+153 | class StringizedReferencesCanBeFixed:
 154 |     def m[S](self: S) -> S:
     |                          ^ PYI019
-155 |         x = cast("S", self)
+155 |         x = cast("list[tuple[S, S]]", self)
 156 |         return x
     |
     = help: Replace TypeVar `S` with `Self`
 
-PYI019_0.py:159:26: PYI019 Use `Self` instead of custom TypeVar `S`
+PYI019_0.py:159:28: PYI019 Use `Self` instead of custom TypeVar `_T`
     |
-158 | class DeletionsAreNotTouched:
-159 |     def m[S](self: S) -> S:
+158 | class ButStrangeStringizedReferencesCannotBeFixed:
+159 |     def m[_T](self: _T) -> _T:
+    |                            ^^ PYI019
+160 |         x = cast('list[_\x54]', self)
+161 |         return x
+    |
+    = help: Replace TypeVar `_T` with `Self`
+
+PYI019_0.py:164:26: PYI019 Use `Self` instead of custom TypeVar `S`
+    |
+163 | class DeletionsAreNotTouched:
+164 |     def m[S](self: S) -> S:
     |                          ^ PYI019
-160 |         # `S` is not a local variable here, and `del` can only be used with local variables,
-161 |         # so `del S` here is not actually a reference to the type variable `S`.
+165 |         # `S` is not a local variable here, and `del` can only be used with local variables,
+166 |         # so `del S` here is not actually a reference to the type variable `S`.
     |
     = help: Replace TypeVar `S` with `Self`
 
-PYI019_0.py:168:26: PYI019 Use `Self` instead of custom TypeVar `S`
+PYI019_0.py:173:26: PYI019 Use `Self` instead of custom TypeVar `S`
     |
-167 | class NamesShadowingTypeVarAreNotTouched:
-168 |     def m[S](self: S) -> S:
+172 | class NamesShadowingTypeVarAreNotTouched:
+173 |     def m[S](self: S) -> S:
     |                          ^ PYI019
-169 |         type S = int
-170 |         print(S)  # not a reference to the type variable, so not touched by the autofix
+174 |         type S = int
+175 |         print(S)  # not a reference to the type variable, so not touched by the autofix
     |
     = help: Replace TypeVar `S` with `Self`

crates/ruff_linter/src/rules/flake8_pyi/snapshots/ruff_linter__rules__flake8_pyi__tests__preview_PYI019_PYI019_0.py.snap

@@ -617,54 +617,76 @@ PYI019_0.py:149:10: PYI019 [*] Use `Self` instead of custom TypeVar `S`
     150 |+        x: type[Self] = type(other)
 151 151 |         return x()
 152 152 | 
-153 153 | class StringizedReferencesAreTooComplicated:
+153 153 | class StringizedReferencesCanBeFixed:
 
-PYI019_0.py:154:10: PYI019 Use `Self` instead of custom TypeVar `S`
+PYI019_0.py:154:10: PYI019 [*] Use `Self` instead of custom TypeVar `S`
     |
-153 | class StringizedReferencesAreTooComplicated:
+153 | class StringizedReferencesCanBeFixed:
 154 |     def m[S](self: S) -> S:
     |          ^^^^^^^^^^^^^^^^^ PYI019
-155 |         x = cast("S", self)
+155 |         x = cast("list[tuple[S, S]]", self)
 156 |         return x
     |
     = help: Replace TypeVar `S` with `Self`
 
-PYI019_0.py:159:10: PYI019 [*] Use `Self` instead of custom TypeVar `S`
+ℹ Safe fix
+151 151 |         return x()
+152 152 | 
+153 153 | class StringizedReferencesCanBeFixed:
+154     |-    def m[S](self: S) -> S:
+155     |-        x = cast("list[tuple[S, S]]", self)
+    154 |+    def m(self) -> Self:
+    155 |+        x = cast("list[tuple[Self, Self]]", self)
+156 156 |         return x
+157 157 | 
+158 158 | class ButStrangeStringizedReferencesCannotBeFixed:
+
+PYI019_0.py:159:10: PYI019 Use `Self` instead of custom TypeVar `_T`
     |
-158 | class DeletionsAreNotTouched:
-159 |     def m[S](self: S) -> S:
+158 | class ButStrangeStringizedReferencesCannotBeFixed:
+159 |     def m[_T](self: _T) -> _T:
+    |          ^^^^^^^^^^^^^^^^^^^^ PYI019
+160 |         x = cast('list[_\x54]', self)
+161 |         return x
+    |
+    = help: Replace TypeVar `_T` with `Self`
+
+PYI019_0.py:164:10: PYI019 [*] Use `Self` instead of custom TypeVar `S`
+    |
+163 | class DeletionsAreNotTouched:
+164 |     def m[S](self: S) -> S:
     |          ^^^^^^^^^^^^^^^^^ PYI019
-160 |         # `S` is not a local variable here, and `del` can only be used with local variables,
-161 |         # so `del S` here is not actually a reference to the type variable `S`.
+165 |         # `S` is not a local variable here, and `del` can only be used with local variables,
+166 |         # so `del S` here is not actually a reference to the type variable `S`.
     |
     = help: Replace TypeVar `S` with `Self`
 
 ℹ Safe fix
-156 156 |         return x
-157 157 | 
-158 158 | class DeletionsAreNotTouched:
-159     |-    def m[S](self: S) -> S:
-    159 |+    def m(self) -> Self:
-160 160 |         # `S` is not a local variable here, and `del` can only be used with local variables,
-161 161 |         # so `del S` here is not actually a reference to the type variable `S`.
-162 162 |         # This `del` statement is therefore not touched by the autofix (it raises `UnboundLocalError`
-
-PYI019_0.py:168:10: PYI019 [*] Use `Self` instead of custom TypeVar `S`
+161 161 |         return x
+162 162 | 
+163 163 | class DeletionsAreNotTouched:
+164     |-    def m[S](self: S) -> S:
+    164 |+    def m(self) -> Self:
+165 165 |         # `S` is not a local variable here, and `del` can only be used with local variables,
+166 166 |         # so `del S` here is not actually a reference to the type variable `S`.
+167 167 |         # This `del` statement is therefore not touched by the autofix (it raises `UnboundLocalError`
+
+PYI019_0.py:173:10: PYI019 [*] Use `Self` instead of custom TypeVar `S`
     |
-167 | class NamesShadowingTypeVarAreNotTouched:
-168 |     def m[S](self: S) -> S:
+172 | class NamesShadowingTypeVarAreNotTouched:
+173 |     def m[S](self: S) -> S:
     |          ^^^^^^^^^^^^^^^^^ PYI019
-169 |         type S = int
-170 |         print(S)  # not a reference to the type variable, so not touched by the autofix
+174 |         type S = int
+175 |         print(S)  # not a reference to the type variable, so not touched by the autofix
     |
     = help: Replace TypeVar `S` with `Self`
 
 ℹ Safe fix
-165 165 |         return self
-166 166 | 
-167 167 | class NamesShadowingTypeVarAreNotTouched:
-168     |-    def m[S](self: S) -> S:
-    168 |+    def m(self) -> Self:
-169 169 |         type S = int
-170 170 |         print(S)  # not a reference to the type variable, so not touched by the autofix
-171 171 |         return 42
+170 170 |         return self
+171 171 | 
+172 172 | class NamesShadowingTypeVarAreNotTouched:
+173     |-    def m[S](self: S) -> S:
+    173 |+    def m(self) -> Self:
+174 174 |         type S = int
+175 175 |         print(S)  # not a reference to the type variable, so not touched by the autofix
+176 176 |         return 42