[ty] Support type:ignore[ty:code] suppressions

Author: MichaReiser

crates/ruff_benchmark/benches/ty.rs

@@ -989,7 +989,7 @@ fn datetype(criterion: &mut Criterion) {
             max_dep_date: "2025-07-04",
             python_version: PythonVersion::PY313,
         },
-        4,
+        10,
     );
 
     bench_project(&benchmark, criterion);

crates/ruff_benchmark/benches/ty_walltime.rs

@@ -109,7 +109,7 @@ static ALTAIR: Benchmark = Benchmark::new(
         max_dep_date: "2025-06-17",
         python_version: PythonVersion::PY312,
     },
-    860,
+    897,
 );
 
 static COLOUR_SCIENCE: Benchmark = Benchmark::new(

crates/ty/docs/rules.md

@@ -161,6 +161,75 @@ mod tests {
         ");
     }
 
+    #[test]
+    fn add_code_existing_type_ignore() {
+        let test = CodeActionTest::with_source(
+            r#"
+            b = <START>a<END> / 0  # type:ignore[ty:division-by-zero]
+        "#,
+        );
+
+        assert_snapshot!(test.code_actions(&UNRESOLVED_REFERENCE), @"
+        info[code-action]: Ignore 'unresolved-reference' for this line
+         --> main.py:2:5
+          |
+        2 | b = a / 0  # type:ignore[ty:division-by-zero]
+          |     ^
+          |
+        1 | 
+          - b = a / 0  # type:ignore[ty:division-by-zero]
+        2 + b = a / 0  # type:ignore[ty:division-by-zero, ty:unresolved-reference]
+        ");
+    }
+
+    #[test]
+    fn add_code_existing_type_ignore_without_any_ty_code() {
+        let test = CodeActionTest::with_source(
+            r#"
+            b = <START>a<END> / 0  # type:ignore[mypy-code]
+        "#,
+        );
+
+        assert_snapshot!(test.code_actions(&UNRESOLVED_REFERENCE), @"
+        info[code-action]: Ignore 'unresolved-reference' for this line
+         --> main.py:2:5
+          |
+        2 | b = a / 0  # type:ignore[mypy-code]
+          |     ^
+          |
+        1 | 
+          - b = a / 0  # type:ignore[mypy-code]
+        2 + b = a / 0  # type:ignore[mypy-code]  # ty:ignore[unresolved-reference]
+        ");
+    }
+
+    #[test]
+    fn add_ignore_existing_file_level_ignore() {
+        let test = CodeActionTest::with_source(
+            r#"
+            # ty:ignore[division-by-zero]
+
+            b = <START>a<END> / 0
+        "#,
+        );
+
+        assert_snapshot!(test.code_actions(&UNRESOLVED_REFERENCE), @"
+        info[code-action]: Ignore 'unresolved-reference' for this line
+         --> main.py:4:5
+          |
+        2 | # ty:ignore[division-by-zero]
+        3 |
+        4 | b = a / 0
+          |     ^
+          |
+        1 | 
+        2 | # ty:ignore[division-by-zero]
+        3 | 
+          - b = a / 0
+        4 + b = a / 0  # ty:ignore[unresolved-reference]
+        ");
+    }
+
     #[test]
     fn add_code_existing_ignore_trailing_comma() {
         let test = CodeActionTest::with_source(

crates/ty_ide/src/code_action.rs

@@ -507,15 +507,15 @@ the class "header":
 
 class A: ...
 
-class B(  # type: ignore[duplicate-base]
+class B(  # type: ignore[ty:duplicate-base]
     A,
     A,
 ): ...
 
 class C(
     A,
     A
-):  # type: ignore[duplicate-base]
+):  # type: ignore[ty:duplicate-base]
     x: int
 
 # fmt: on
@@ -532,7 +532,7 @@ exception at runtime, not a sub-expression in the class's bases list.
 class D(
     A,
     # error: [unused-type-ignore-comment]
-    A,  # type: ignore[duplicate-base]
+    A,  # type: ignore[ty:duplicate-base]
 ): ...
 
 # error: [duplicate-base]
@@ -541,7 +541,7 @@ class E(
     A
 ):
     # error: [unused-type-ignore-comment]
-    x: int  # type: ignore[duplicate-base]
+    x: int  # type: ignore[ty:duplicate-base]
 
 # fmt: on
 ```

crates/ty_python_semantic/resources/mdtest/mro.md

@@ -66,15 +66,15 @@ mdtest path: crates/ty_python_semantic/resources/mdtest/mro.md
 51 | 
 52 | class A: ...
 53 | 
-54 | class B(  # type: ignore[duplicate-base]
+54 | class B(  # type: ignore[ty:duplicate-base]
 55 |     A,
 56 |     A,
 57 | ): ...
 58 | 
 59 | class C(
 60 |     A,
 61 |     A
-62 | ):  # type: ignore[duplicate-base]
+62 | ):  # type: ignore[ty:duplicate-base]
 63 |     x: int
 64 | 
 65 | # fmt: on
@@ -84,7 +84,7 @@ mdtest path: crates/ty_python_semantic/resources/mdtest/mro.md
 69 | class D(
 70 |     A,
 71 |     # error: [unused-type-ignore-comment]
-72 |     A,  # type: ignore[duplicate-base]
+72 |     A,  # type: ignore[ty:duplicate-base]
 73 | ): ...
 74 | 
 75 | # error: [duplicate-base]
@@ -93,7 +93,7 @@ mdtest path: crates/ty_python_semantic/resources/mdtest/mro.md
 78 |     A
 79 | ):
 80 |     # error: [unused-type-ignore-comment]
-81 |     x: int  # type: ignore[duplicate-base]
+81 |     x: int  # type: ignore[ty:duplicate-base]
 82 | 
 83 | # fmt: on
 ```
@@ -281,7 +281,7 @@ error[duplicate-base]: Duplicate base class `A`
    |  _______^
 70 | |     A,
 71 | |     # error: [unused-type-ignore-comment]
-72 | |     A,  # type: ignore[duplicate-base]
+72 | |     A,  # type: ignore[ty:duplicate-base]
 73 | | ): ...
    | |_^
 74 |
@@ -295,7 +295,7 @@ info: The definition of class `D` will raise `TypeError` at runtime
 70 |     A,
    |     - Class `A` first included in bases list here
 71 |     # error: [unused-type-ignore-comment]
-72 |     A,  # type: ignore[duplicate-base]
+72 |     A,  # type: ignore[ty:duplicate-base]
    |     ^ Class `A` later repeated here
 73 | ): ...
    |
@@ -304,20 +304,20 @@ info: rule `duplicate-base` is enabled by default
 ```
 
 ```
-warning[unused-type-ignore-comment]: Unused blanket `type: ignore` directive
+warning[unused-type-ignore-comment]: Unused `type: ignore` directive
   --> src/mdtest_snippet.py:72:9
    |
 70 |     A,
 71 |     # error: [unused-type-ignore-comment]
-72 |     A,  # type: ignore[duplicate-base]
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+72 |     A,  # type: ignore[ty:duplicate-base]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 73 | ): ...
    |
 help: Remove the unused suppression comment
 69 | class D(
 70 |     A,
 71 |     # error: [unused-type-ignore-comment]
-   -     A,  # type: ignore[duplicate-base]
+   -     A,  # type: ignore[ty:duplicate-base]
 72 +     A,
 73 | ): ...
 74 | 
@@ -337,7 +337,7 @@ error[duplicate-base]: Duplicate base class `A`
 79 | | ):
    | |_^
 80 |       # error: [unused-type-ignore-comment]
-81 |       x: int  # type: ignore[duplicate-base]
+81 |       x: int  # type: ignore[ty:duplicate-base]
    |
 info: The definition of class `E` will raise `TypeError` at runtime
   --> src/mdtest_snippet.py:77:5
@@ -356,21 +356,21 @@ info: rule `duplicate-base` is enabled by default
 ```
 
 ```
-warning[unused-type-ignore-comment]: Unused blanket `type: ignore` directive
+warning[unused-type-ignore-comment]: Unused `type: ignore` directive
   --> src/mdtest_snippet.py:81:13
    |
 79 | ):
 80 |     # error: [unused-type-ignore-comment]
-81 |     x: int  # type: ignore[duplicate-base]
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+81 |     x: int  # type: ignore[ty:duplicate-base]
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 82 |
 83 | # fmt: on
    |
 help: Remove the unused suppression comment
 78 |     A
 79 | ):
 80 |     # error: [unused-type-ignore-comment]
-   -     x: int  # type: ignore[duplicate-base]
+   -     x: int  # type: ignore[ty:duplicate-base]
 81 +     x: int
 82 | 
 83 | # fmt: on

crates/ty_python_semantic/resources/mdtest/snapshots/mro.md_-_Method_Resolution_Or…_-_`__bases__`_lists_wi…_(ea7ebc83ec359b54).snap

@@ -0,0 +1,35 @@
+---
+source: crates/ty_test/src/lib.rs
+expression: snapshot
+---
+
+---
+mdtest name: type_ignore.md - Suppressing errors with `type: ignore` - Unused ignore comment mixed with mypy comments
+mdtest path: crates/ty_python_semantic/resources/mdtest/suppressions/type_ignore.md
+---
+
+# Python source files
+
+## mdtest_snippet.py
+
+```
+1 | # error: [unused-type-ignore-comment] "Unused `type: ignore` directive: 'division-by-zero'"
+2 | a = 10 / 2  # type: ignore[mypy-code, ty:division-by-zero]
+```
+
+# Diagnostics
+
+```
+warning[unused-type-ignore-comment]: Unused `type: ignore` directive: 'division-by-zero'
+ --> src/mdtest_snippet.py:2:39
+  |
+1 | # error: [unused-type-ignore-comment] "Unused `type: ignore` directive: 'division-by-zero'"
+2 | a = 10 / 2  # type: ignore[mypy-code, ty:division-by-zero]
+  |                                       ^^^^^^^^^^^^^^^^^^^
+  |
+help: Remove the unused suppression code
+1 | # error: [unused-type-ignore-comment] "Unused `type: ignore` directive: 'division-by-zero'"
+  - a = 10 / 2  # type: ignore[mypy-code, ty:division-by-zero]
+2 + a = 10 / 2  # type: ignore[mypy-code]
+
+```

crates/ty_python_semantic/resources/mdtest/snapshots/type_ignore.md_-_Suppressing_errors_w…_-_Unused_ignore_commen…_(9c991af56eb6f4e3).snap

@@ -167,15 +167,13 @@ a = 4 / 0  # ty: ignore[]
 
 ## File-level suppression comments
 
-File level suppression comments are currently intentionally unsupported because we've yet to decide
-if they should use a different syntax that also supports enabling rules or changing the rule's
-severity: `ty: possibly-undefined-reference=error`
+File level suppression comments suppress all errors in a file with a given code.
 
 ```py
-# error: [unused-ignore-comment]
 # ty: ignore[division-by-zero]
 
-a = 4 / 0  # error: [division-by-zero]
+a = 4 / 0
+b = a + c  # error: [unresolved-reference]
 ```
 
 ## Unknown rule

crates/ty_python_semantic/resources/mdtest/suppressions/ty_ignore.md

@@ -132,11 +132,19 @@ a = f"""
 
 ## Codes
 
-Mypy supports `type: ignore[code]`. ty doesn't understand mypy's rule names. Therefore, ignore the
-codes and suppress all errors.
+Similar to mypy support `type: ignore[codes]` comments. But unlike mypy, ty only respects codes
+starting with `ty:` to avoid ambiguity with suppression comments from mypy and other type checkers.
 
 ```py
-a = test  # type: ignore[name-defined]
+a = test  # type: ignore[name-defined, ty:unresolved-reference]
+```
+
+## Unknown codes starting with `ty`
+
+```py
+# error: [unresolved-reference]
+# error: [ignore-comment-unknown-rule]
+a = test  # type: ignore[ty:name-defined]
 ```
 
 ## Nested comments
@@ -190,6 +198,15 @@ a = 10 / 0
 b = a / 0
 ```
 
+## File level suppression with code
+
+```py
+# type: ignore[ty:division-by-zero]
+
+a = 10 / 0
+b = a + c  # error: [unresolved-reference]
+```
+
 ## File level suppression with leading shebang
 
 ```py
@@ -242,3 +259,26 @@ ty doesn't report invalid `type: ignore` comments:
 ```py
 a = 10 + 4  # type: ignoreee
 ```
+
+## Unused ignore comment mixed with mypy comments
+
+<!-- snapshot-diagnostics -->
+
+```py
+# error: [unused-type-ignore-comment] "Unused `type: ignore` directive: 'division-by-zero'"
+a = 10 / 2  # type: ignore[mypy-code, ty:division-by-zero]
+```
+
+## Unused ignore comment
+
+```py
+# error: [unused-type-ignore-comment] "Unused `type: ignore` directive"
+a = 10 / 2  # type: ignore[ty:division-by-zero]
+```
+
+## Unknown ignore code
+
+```py
+# error: [ignore-comment-unknown-rule] "Unknown rule `division-by`. Did you mean"
+a = 10 / 2  # type: ignore[ty:division-by]
+```