Improve `SIM117` (#1867)

This PR makes the following changes to improve `SIM117`:

- Avoid emitting `SIM117` multiple times within the same `with`
statement:
- Adjust the error range.  


## Example

```python
with A() as a:  # SIM117
    with B() as b:
        with C() as c:
            print("hello")
```

### Current

```
resources/test/fixtures/flake8_simplify/SIM117.py:5:1: SIM117 Use a single `with` statement with multiple contexts instead of nested `with` statements
  |
5 | / with A() as a:  # SIM117
6 | |     with B() as b:
7 | |         with C() as c:
8 | |             print("hello")
  | |__________________________^ SIM117
  |

resources/test/fixtures/flake8_simplify/SIM117.py:6:5: SIM117 Use a single `with` statement with multiple contexts instead of nested `with` statements
  |
6 |       with B() as b:
  |  _____^
7 | |         with C() as c:
8 | |             print("hello")
  | |__________________________^ SIM117
  |
```

### Improved

```
resources/test/fixtures/flake8_simplify/SIM117.py:5:1: SIM117 Use a single `with` statement with multiple contexts instead of nested `with` statements
  |
5 | / with A() as a:  # SIM117
6 | |     with B() as b:
7 | |         with C() as c:
  | |______________________^ SIM117
  |
```

Signed-off-by: harupy <hkawamura0130@gmail.com>

resources/test/fixtures/flake8_simplify/SIM117.py

@@ -2,6 +2,11 @@ with A() as a:  # SIM117
     with B() as b:
         print("hello")
 
+with A():  # SIM117
+    with B():
+        with C():
+            print("hello")
+
 with A() as a:
     a()
     with B() as b:

src/ast/helpers.rs

@@ -622,6 +622,19 @@ pub fn preceded_by_continuation(stmt: &Stmt, locator: &Locator) -> bool {
     false
 }
 
+/// Return the `Range` of the first `Tok::Colon` token in a `Range`.
+pub fn first_colon_range(range: Range, locator: &Locator) -> Option<Range> {
+    let contents = locator.slice_source_code_range(&range);
+    let range = lexer::make_tokenizer_located(&contents, range.location)
+        .flatten()
+        .find(|(_, kind, _)| matches!(kind, Tok::Colon))
+        .map(|(location, _, end_location)| Range {
+            location,
+            end_location,
+        });
+    range
+}
+
 /// Return `true` if a `Stmt` appears to be part of a multi-statement line, with
 /// other statements preceding it.
 pub fn preceded_by_multi_statement_line(stmt: &Stmt, locator: &Locator) -> bool {
@@ -708,7 +721,9 @@ mod tests {
     use rustpython_ast::Location;
     use rustpython_parser::parser;
 
-    use crate::ast::helpers::{else_range, identifier_range, match_trailing_content};
+    use crate::ast::helpers::{
+        else_range, first_colon_range, identifier_range, match_trailing_content,
+    };
     use crate::ast::types::Range;
     use crate::source_code::Locator;
 
@@ -839,4 +854,19 @@ else:
         assert_eq!(range.end_location.column(), 4);
         Ok(())
     }
+
+    #[test]
+    fn test_first_colon_range() {
+        let contents = "with a: pass";
+        let locator = Locator::new(contents);
+        let range = first_colon_range(
+            Range::new(Location::new(1, 0), Location::new(1, contents.len())),
+            &locator,
+        )
+        .unwrap();
+        assert_eq!(range.location.row(), 1);
+        assert_eq!(range.location.column(), 6);
+        assert_eq!(range.end_location.row(), 1);
+        assert_eq!(range.end_location.column(), 7);
+    }
 }

src/checkers/ast.rs

@@ -1283,7 +1283,12 @@ where
                     flake8_pytest_style::rules::complex_raises(self, stmt, items, body);
                 }
                 if self.settings.enabled.contains(&RuleCode::SIM117) {
-                    flake8_simplify::rules::multiple_with_statements(self, stmt);
+                    flake8_simplify::rules::multiple_with_statements(
+                        self,
+                        stmt,
+                        body,
+                        self.current_stmt_parent().map(|parent| parent.0),
+                    );
                 }
             }
             StmtKind::While { body, orelse, .. } => {

src/flake8_simplify/rules/ast_with.rs

@@ -1,22 +1,51 @@
-use rustpython_ast::{Stmt, StmtKind};
+use rustpython_ast::{Located, Stmt, StmtKind, Withitem};
 
+use crate::ast::helpers::first_colon_range;
 use crate::ast::types::Range;
 use crate::checkers::ast::Checker;
 use crate::registry::Diagnostic;
 use crate::violations;
 
+fn find_last_with(body: &[Stmt]) -> Option<(&Vec<Withitem>, &Vec<Stmt>)> {
+    let [Located { node: StmtKind::With { items, body, .. }, ..}] = body else { return None };
+    find_last_with(body).or(Some((items, body)))
+}
+
 /// SIM117
-pub fn multiple_with_statements(checker: &mut Checker, stmt: &Stmt) {
+pub fn multiple_with_statements(
-    let StmtKind::With { body, .. } = &stmt.node else {
+    checker: &mut Checker,
-        return;
+    with_stmt: &Stmt,
-    };
+    with_body: &[Stmt],
-    if body.len() != 1 {
+    with_parent: Option<&Stmt>,
-        return;
+) {
+    if let Some(parent) = with_parent {
+        if let StmtKind::With { body, .. } = &parent.node {
+            if body.len() == 1 {
+                return;
+            }
+        }
     }
-    if matches!(body[0].node, StmtKind::With { .. }) {
+    if let Some((items, body)) = find_last_with(with_body) {
+        let last_item = items.last().expect("Expected items to be non-empty");
+        let colon = first_colon_range(
+            Range::new(
+                last_item
+                    .optional_vars
+                    .as_ref()
+                    .map_or(last_item.context_expr.end_location, |v| v.end_location)
+                    .unwrap(),
+                body.first()
+                    .expect("Expected body to be non-empty")
+                    .location,
+            ),
+            checker.locator,
+        );
         checker.diagnostics.push(Diagnostic::new(
             violations::MultipleWithStatements,
-            Range::from_located(stmt),
+            colon.map_or_else(
+                || Range::from_located(with_stmt),
+                |colon| Range::new(with_stmt.location, colon.end_location),
+            ),
         ));
     }
 }

src/flake8_simplify/snapshots/ruff__flake8_simplify__tests__SIM117_SIM117.py.snap

@@ -1,6 +1,6 @@
 ---
 source: src/flake8_simplify/mod.rs
-expression: checks
+expression: diagnostics
 ---
 - kind:
     MultipleWithStatements: ~
@@ -8,8 +8,18 @@ expression: checks
     row: 1
     column: 0
   end_location:
-    row: 3
+    row: 2
-    column: 22
+    column: 18
+  fix: ~
+  parent: ~
+- kind:
+    MultipleWithStatements: ~
+  location:
+    row: 5
+    column: 0
+  end_location:
+    row: 7
+    column: 17
   fix: ~
   parent: ~