Automatically remove empty type-checking blocks (#2598)

README.md

@@ -1232,7 +1232,7 @@ For more, see [flake8-type-checking](https://pypi.org/project/flake8-type-checki
 | TCH002 | typing-only-third-party-import | Move third-party import `{}` into a type-checking block |  |
 | TCH003 | typing-only-standard-library-import | Move standard library import `{}` into a type-checking block |  |
 | TCH004 | runtime-import-in-type-checking-block | Move import `{}` out of type-checking block. Import is used for more than type hinting. |  |
-| TCH005 | empty-type-checking-block | Found empty type-checking block |  |
+| TCH005 | empty-type-checking-block | Found empty type-checking block | 🛠 |
 
 ### flake8-unused-arguments (ARG)
 

crates/ruff/src/checkers/ast.rs

@@ -1937,7 +1937,7 @@ where
 
                 if flake8_type_checking::helpers::is_type_checking_block(self, test) {
                     if self.settings.rules.enabled(&Rule::EmptyTypeCheckingBlock) {
-                        flake8_type_checking::rules::empty_type_checking_block(self, body);
+                        flake8_type_checking::rules::empty_type_checking_block(self, stmt, body);
                     }
 
                     let prev_in_type_checking_block = self.in_type_checking_block;

crates/ruff/src/rules/flake8_type_checking/rules/empty_type_checking_block.rs

@@ -1,29 +1,69 @@
+use log::error;
 use rustpython_ast::{Stmt, StmtKind};
 
 use ruff_macros::derive_message_formats;
 
-use crate::ast::types::Range;
+use crate::ast::types::{Range, RefEquality};
+use crate::autofix::helpers::delete_stmt;
 use crate::checkers::ast::Checker;
 use crate::define_violation;
 use crate::registry::Diagnostic;
-use crate::violation::Violation;
+use crate::violation::AlwaysAutofixableViolation;
 
 define_violation!(
     pub struct EmptyTypeCheckingBlock;
 );
-impl Violation for EmptyTypeCheckingBlock {
+impl AlwaysAutofixableViolation for EmptyTypeCheckingBlock {
     #[derive_message_formats]
     fn message(&self) -> String {
         format!("Found empty type-checking block")
     }
+
+    fn autofix_title(&self) -> String {
+        format!("Delete empty type-checking block")
+    }
 }
 
 /// TCH005
-pub fn empty_type_checking_block(checker: &mut Checker, body: &[Stmt]) {
+pub fn empty_type_checking_block<'a, 'b>(
+    checker: &mut Checker<'a>,
+    stmt: &'a Stmt,
+    body: &'a [Stmt],
+) where
+    'b: 'a,
+{
     if body.len() == 1 && matches!(body[0].node, StmtKind::Pass) {
-        checker.diagnostics.push(Diagnostic::new(
-            EmptyTypeCheckingBlock,
-            Range::from_located(&body[0]),
-        ));
+        let mut diagnostic = Diagnostic::new(EmptyTypeCheckingBlock, Range::from_located(&body[0]));
+
+        // Delete the entire type-checking block.
+        if checker.patch(diagnostic.kind.rule()) {
+            let parent = checker
+                .child_to_parent
+                .get(&RefEquality(stmt))
+                .map(std::convert::Into::into);
+            let deleted: Vec<&Stmt> = checker
+                .deletions
+                .iter()
+                .map(std::convert::Into::into)
+                .collect();
+            match delete_stmt(
+                stmt,
+                parent,
+                &deleted,
+                checker.locator,
+                checker.indexer,
+                checker.stylist,
+            ) {
+                Ok(fix) => {
+                    if fix.content.is_empty() || fix.content == "pass" {
+                        checker.deletions.insert(RefEquality(stmt));
+                    }
+                    diagnostic.amend(fix);
+                }
+                Err(e) => error!("Failed to remove empty type-checking block: {e}"),
+            }
+        }
+
+        checker.diagnostics.push(diagnostic);
     }
 }

crates/ruff/src/rules/flake8_type_checking/snapshots/ruff__rules__flake8_type_checking__tests__empty-type-checking-block_TCH005.py.snap

@@ -1,5 +1,5 @@
 ---
-source: src/rules/flake8_type_checking/mod.rs
+source: crates/ruff/src/rules/flake8_type_checking/mod.rs
 expression: diagnostics
 ---
 - kind:
@@ -10,7 +10,15 @@ expression: diagnostics
   end_location:
     row: 4
     column: 8
-  fix: ~
+  fix:
+    content:
+      - ""
+    location:
+      row: 3
+      column: 0
+    end_location:
+      row: 5
+      column: 0
   parent: ~
 - kind:
     EmptyTypeCheckingBlock: ~
@@ -20,7 +28,15 @@ expression: diagnostics
   end_location:
     row: 8
     column: 8
-  fix: ~
+  fix:
+    content:
+      - ""
+    location:
+      row: 7
+      column: 0
+    end_location:
+      row: 9
+      column: 0
   parent: ~
 - kind:
     EmptyTypeCheckingBlock: ~
@@ -30,7 +46,15 @@ expression: diagnostics
   end_location:
     row: 11
     column: 8
-  fix: ~
+  fix:
+    content:
+      - ""
+    location:
+      row: 10
+      column: 0
+    end_location:
+      row: 12
+      column: 0
   parent: ~
 - kind:
     EmptyTypeCheckingBlock: ~
@@ -40,7 +64,15 @@ expression: diagnostics
   end_location:
     row: 16
     column: 12
-  fix: ~
+  fix:
+    content:
+      - ""
+    location:
+      row: 15
+      column: 0
+    end_location:
+      row: 17
+      column: 0
   parent: ~
 - kind:
     EmptyTypeCheckingBlock: ~
@@ -50,6 +82,14 @@ expression: diagnostics
   end_location:
     row: 22
     column: 12
-  fix: ~
+  fix:
+    content:
+      - ""
+    location:
+      row: 21
+      column: 0
+    end_location:
+      row: 23
+      column: 0
   parent: ~