Handled dict and set inside f-string (#4249) (#4563)

crates/ruff/resources/test/fixtures/flake8_comprehensions/C401.py

@@ -1,13 +1,20 @@
 x = set(x for x in range(3))
-x = set(
+x = set(x for x in range(3))
-    x for x in range(3)
+y = f"{set(a if a < 6 else 0  for a in range(3))}"
-)
+_ = "{}".format(set(a if a < 6 else 0 for a in range(3)))
-y = f'{set(a if a < 6 else 0  for a in range(3))}'
+print(f"Hello {set(a for a in range(3))} World")
-_ = '{}'.format(set(a if a < 6 else 0  for a in range(3)))
-print(f'Hello {set(a for a in range(3))} World')
-
-def set(*args, **kwargs):
-    return None
 
 
-set(x for x in range(3))
+def f(x):
+    return x
+
+
+print(f'Hello {set(a for a in "abc")} World')
+print(f"Hello {set(a for a in 'abc')} World")
+print(f"Hello {set(f(a) for a in 'abc')} World")
+print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
+
+# The fix generated for this diagnostic is incorrect, as we add additional space
+# around the set comprehension.
+print(f"{ {set(a for a in 'abc')} }")

crates/ruff/resources/test/fixtures/flake8_comprehensions/C402.py

@@ -5,3 +5,14 @@ dict(
 dict(((x, x) for x in range(3)), z=3)
 y = f'{dict((x, x) for x in range(3))}'
 print(f'Hello {dict((x, x) for x in range(3))} World')
+print(f"Hello {dict((x, x) for x in 'abc')} World")
+print(f'Hello {dict((x, x) for x in "abc")} World')
+print(f'Hello {dict((x,x) for x in "abc")} World')
+
+f'{dict((x, x) for x in range(3)) | dict((x, x) for x in range(3))}'
+f'{ dict((x, x) for x in range(3)) | dict((x, x) for x in range(3)) }'
+
+def f(x):
+    return x
+
+print(f'Hello {dict((x,f(x)) for x in "abc")} World')

crates/ruff/resources/test/fixtures/flake8_comprehensions/C403.py

@@ -2,3 +2,14 @@ s = set([x for x in range(3)])
 s = set(
     [x for x in range(3)]
 )
+
+s = f"{set([x for x in 'ab'])}"
+s = f'{set([x for x in "ab"])}'
+
+def f(x):
+    return x
+
+s = f"{set([f(x) for x in 'ab'])}"
+
+s = f"{ set([x for x in 'ab']) | set([x for x in 'ab']) }"
+s = f"{set([x for x in 'ab']) | set([x for x in 'ab'])}"

crates/ruff/resources/test/fixtures/flake8_comprehensions/C404.py

@@ -1,2 +1,13 @@
 dict([(i, i) for i in range(3)])
 dict([(i, i) for i in range(3)], z=4)
+
+def f(x):
+    return x
+
+f'{dict([(s,s) for s in "ab"])}'
+f"{dict([(s,s) for s in 'ab'])}"
+f"{dict([(s, s) for s in 'ab'])}"
+f"{dict([(s,f(s)) for s in 'ab'])}"
+
+f'{dict([(s,s) for s in "ab"]) | dict([(s,s) for s in "ab"])}'
+f'{ dict([(s,s) for s in "ab"]) | dict([(s,s) for s in "ab"]) }'

crates/ruff/resources/test/fixtures/flake8_comprehensions/C405.py

@@ -16,3 +16,11 @@ set(
 set(
     [1,]
 )
+f"{set([1,2,3])}"
+f"{set(['a', 'b'])}"
+f'{set(["a", "b"])}'
+
+f"{set(['a', 'b']) - set(['a'])}"
+f"{ set(['a', 'b']) - set(['a']) }"
+f"a {set(['a', 'b']) - set(['a'])} b"
+f"a { set(['a', 'b']) - set(['a']) } b"

crates/ruff/resources/test/fixtures/flake8_comprehensions/C408.py

@@ -10,3 +10,13 @@ def list():
 
 
 a = list()
+
+f"{dict(x='y')}"
+f'{dict(x="y")}'
+f"{dict()}"
+f"a {dict()} b"
+
+f"{dict(x='y') | dict(y='z')}"
+f"{ dict(x='y') | dict(y='z') }"
+f"a {dict(x='y') | dict(y='z')} b"
+f"a { dict(x='y') | dict(y='z') } b"

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

@@ -136,19 +136,27 @@ impl<'a> Checker<'a> {
 
     /// Create a [`Generator`] to generate source code based on the current AST state.
     pub(crate) fn generator(&self) -> Generator {
-        fn quote_style(
+        Generator::new(
-            model: &SemanticModel,
+            self.stylist.indentation(),
-            locator: &Locator,
+            self.f_string_quote_style().unwrap_or(self.stylist.quote()),
-            indexer: &Indexer,
+            self.stylist.line_ending(),
-        ) -> Option<Quote> {
+        )
+    }
+
+    /// Returns the appropriate quoting for f-string by reversing the one used outside of
+    /// the f-string.
+    ///
+    /// If the current expression in the context is not an f-string, returns ``None``.
+    pub(crate) fn f_string_quote_style(&self) -> Option<Quote> {
+        let model = &self.semantic_model;
         if !model.in_f_string() {
             return None;
         }
 
         // Find the quote character used to start the containing f-string.
         let expr = model.expr()?;
-            let string_range = indexer.f_string_range(expr.start())?;
+        let string_range = self.indexer.f_string_range(expr.start())?;
-            let trailing_quote = trailing_quote(locator.slice(string_range))?;
+        let trailing_quote = trailing_quote(self.locator.slice(string_range))?;
 
         // Invert the quote character, if it's a single quote.
         match *trailing_quote {
@@ -158,14 +166,6 @@ impl<'a> Checker<'a> {
         }
     }
 
-        Generator::new(
-            self.stylist.indentation(),
-            quote_style(&self.semantic_model, self.locator, self.indexer)
-                .unwrap_or(self.stylist.quote()),
-            self.stylist.line_ending(),
-        )
-    }
-
     /// Returns the [`IsolationLevel`] for fixes in the current context.
     ///
     /// The primary use-case for fix isolation is to ensure that we don't delete all statements
@@ -2729,22 +2729,12 @@ where
                 }
                 if self.enabled(Rule::UnnecessaryGeneratorSet) {
                     flake8_comprehensions::rules::unnecessary_generator_set(
-                        self,
+                        self, expr, func, args, keywords,
-                        expr,
-                        self.semantic_model.expr_parent(),
-                        func,
-                        args,
-                        keywords,
                     );
                 }
                 if self.enabled(Rule::UnnecessaryGeneratorDict) {
                     flake8_comprehensions::rules::unnecessary_generator_dict(
-                        self,
+                        self, expr, func, args, keywords,
-                        expr,
-                        self.semantic_model.expr_parent(),
-                        func,
-                        args,
-                        keywords,
                     );
                 }
                 if self.enabled(Rule::UnnecessaryListComprehensionSet) {

crates/ruff/src/rules/flake8_comprehensions/fixes.rs

@@ -7,15 +7,19 @@ use libcst_native::{
     RightParen, RightSquareBracket, Set, SetComp, SimpleString, SimpleWhitespace,
     TrailingWhitespace, Tuple,
 };
+use ruff_text_size::TextRange;
 use rustpython_parser::ast::Ranged;
 
-use crate::autofix::codemods::CodegenStylist;
 use ruff_diagnostics::{Edit, Fix};
 use ruff_python_ast::source_code::{Locator, Stylist};
 
-use crate::cst::matchers::{
+use crate::autofix::codemods::CodegenStylist;
+use crate::{
+    checkers::ast::Checker,
+    cst::matchers::{
         match_arg, match_call, match_call_mut, match_expression, match_generator_exp, match_lambda,
         match_list_comp, match_name, match_tuple,
+    },
 };
 
 /// (C400) Convert `list(x for x in y)` to `[x for x in y]`.
@@ -53,11 +57,12 @@ pub(crate) fn fix_unnecessary_generator_list(
 
 /// (C401) Convert `set(x for x in y)` to `{x for x in y}`.
 pub(crate) fn fix_unnecessary_generator_set(
-    locator: &Locator,
+    checker: &Checker,
-    stylist: &Stylist,
     expr: &rustpython_parser::ast::Expr,
-    parent: Option<&rustpython_parser::ast::Expr>,
 ) -> Result<Edit> {
+    let locator = checker.locator;
+    let stylist = checker.stylist;
+
     // Expr(Call(GeneratorExp)))) -> Expr(SetComp)))
     let module_text = locator.slice(expr.range());
     let mut tree = match_expression(module_text)?;
@@ -79,25 +84,23 @@ pub(crate) fn fix_unnecessary_generator_set(
         rpar: generator_exp.rpar.clone(),
     }));
 
-    let mut content = tree.codegen_stylist(stylist);
+    let content = tree.codegen_stylist(stylist);
 
-    // If the expression is embedded in an f-string, surround it with spaces to avoid
+    Ok(Edit::range_replacement(
-    // syntax errors.
+        pad_expression(content, expr.range(), checker),
-    if let Some(rustpython_parser::ast::Expr::FormattedValue(_)) = parent {
+        expr.range(),
-        content = format!(" {content} ");
+    ))
-    }
-
-    Ok(Edit::range_replacement(content, expr.range()))
 }
 
 /// (C402) Convert `dict((x, x) for x in range(3))` to `{x: x for x in
 /// range(3)}`.
 pub(crate) fn fix_unnecessary_generator_dict(
-    locator: &Locator,
+    checker: &Checker,
-    stylist: &Stylist,
     expr: &rustpython_parser::ast::Expr,
-    parent: Option<&rustpython_parser::ast::Expr>,
 ) -> Result<Edit> {
+    let locator = checker.locator;
+    let stylist = checker.stylist;
+
     let module_text = locator.slice(expr.range());
     let mut tree = match_expression(module_text)?;
     let call = match_call_mut(&mut tree)?;
@@ -126,23 +129,19 @@ pub(crate) fn fix_unnecessary_generator_dict(
         whitespace_after_colon: ParenthesizableWhitespace::SimpleWhitespace(SimpleWhitespace(" ")),
     }));
 
-    let mut content = tree.codegen_stylist(stylist);
+    Ok(Edit::range_replacement(
-
+        pad_expression(tree.codegen_stylist(stylist), expr.range(), checker),
-    // If the expression is embedded in an f-string, surround it with spaces to avoid
+        expr.range(),
-    // syntax errors.
+    ))
-    if let Some(rustpython_parser::ast::Expr::FormattedValue(_)) = parent {
-        content = format!(" {content} ");
-    }
-
-    Ok(Edit::range_replacement(content, expr.range()))
 }
 
 /// (C403) Convert `set([x for x in y])` to `{x for x in y}`.
 pub(crate) fn fix_unnecessary_list_comprehension_set(
-    locator: &Locator,
+    checker: &Checker,
-    stylist: &Stylist,
     expr: &rustpython_parser::ast::Expr,
 ) -> Result<Edit> {
+    let locator = checker.locator;
+    let stylist = checker.stylist;
     // Expr(Call(ListComp)))) ->
     // Expr(SetComp)))
     let module_text = locator.slice(expr.range());
@@ -166,7 +165,7 @@ pub(crate) fn fix_unnecessary_list_comprehension_set(
     }));
 
     Ok(Edit::range_replacement(
-        tree.codegen_stylist(stylist),
+        pad_expression(tree.codegen_stylist(stylist), expr.range(), checker),
         expr.range(),
     ))
 }
@@ -174,10 +173,12 @@ pub(crate) fn fix_unnecessary_list_comprehension_set(
 /// (C404) Convert `dict([(i, i) for i in range(3)])` to `{i: i for i in
 /// range(3)}`.
 pub(crate) fn fix_unnecessary_list_comprehension_dict(
-    locator: &Locator,
+    checker: &Checker,
-    stylist: &Stylist,
     expr: &rustpython_parser::ast::Expr,
 ) -> Result<Edit> {
+    let locator = checker.locator;
+    let stylist = checker.stylist;
+
     let module_text = locator.slice(expr.range());
     let mut tree = match_expression(module_text)?;
     let call = match_call_mut(&mut tree)?;
@@ -188,16 +189,15 @@ pub(crate) fn fix_unnecessary_list_comprehension_dict(
     let tuple = match_tuple(&list_comp.elt)?;
 
     let [Element::Simple {
-            value: key,
+            value: key, ..
-            comma: Some(comma),
         }, Element::Simple { value, .. }] = &tuple.elements[..] else { bail!("Expected tuple with two elements"); };
 
     tree = Expression::DictComp(Box::new(DictComp {
         key: Box::new(key.clone()),
         value: Box::new(value.clone()),
         for_in: list_comp.for_in.clone(),
-        whitespace_before_colon: comma.whitespace_before.clone(),
+        whitespace_before_colon: ParenthesizableWhitespace::default(),
-        whitespace_after_colon: comma.whitespace_after.clone(),
+        whitespace_after_colon: ParenthesizableWhitespace::SimpleWhitespace(SimpleWhitespace(" ")),
         lbrace: LeftCurlyBrace {
             whitespace_after: call.whitespace_before_args.clone(),
         },
@@ -209,7 +209,7 @@ pub(crate) fn fix_unnecessary_list_comprehension_dict(
     }));
 
     Ok(Edit::range_replacement(
-        tree.codegen_stylist(stylist),
+        pad_expression(tree.codegen_stylist(stylist), expr.range(), checker),
         expr.range(),
     ))
 }
@@ -259,10 +259,12 @@ fn drop_trailing_comma<'a>(
 
 /// (C405) Convert `set((1, 2))` to `{1, 2}`.
 pub(crate) fn fix_unnecessary_literal_set(
-    locator: &Locator,
+    checker: &Checker,
-    stylist: &Stylist,
     expr: &rustpython_parser::ast::Expr,
 ) -> Result<Edit> {
+    let locator = checker.locator;
+    let stylist = checker.stylist;
+
     // Expr(Call(List|Tuple)))) -> Expr(Set)))
     let module_text = locator.slice(expr.range());
     let mut tree = match_expression(module_text)?;
@@ -294,17 +296,19 @@ pub(crate) fn fix_unnecessary_literal_set(
     }
 
     Ok(Edit::range_replacement(
-        tree.codegen_stylist(stylist),
+        pad_expression(tree.codegen_stylist(stylist), expr.range(), checker),
         expr.range(),
     ))
 }
 
 /// (C406) Convert `dict([(1, 2)])` to `{1: 2}`.
 pub(crate) fn fix_unnecessary_literal_dict(
-    locator: &Locator,
+    checker: &Checker,
-    stylist: &Stylist,
     expr: &rustpython_parser::ast::Expr,
 ) -> Result<Edit> {
+    let locator = checker.locator;
+    let stylist = checker.stylist;
+
     // Expr(Call(List|Tuple)))) -> Expr(Dict)))
     let module_text = locator.slice(expr.range());
     let mut tree = match_expression(module_text)?;
@@ -358,36 +362,50 @@ pub(crate) fn fix_unnecessary_literal_dict(
     }));
 
     Ok(Edit::range_replacement(
-        tree.codegen_stylist(stylist),
+        pad_expression(tree.codegen_stylist(stylist), expr.range(), checker),
         expr.range(),
     ))
 }
 
 /// (C408)
 pub(crate) fn fix_unnecessary_collection_call(
-    locator: &Locator,
+    checker: &Checker,
-    stylist: &Stylist,
     expr: &rustpython_parser::ast::Expr,
 ) -> Result<Edit> {
+    enum Collection {
+        Tuple,
+        List,
+        Dict,
+    }
+
+    let locator = checker.locator;
+    let stylist = checker.stylist;
+
     // Expr(Call("list" | "tuple" | "dict")))) -> Expr(List|Tuple|Dict)
     let module_text = locator.slice(expr.range());
     let mut tree = match_expression(module_text)?;
-    let call = match_call_mut(&mut tree)?;
+    let call = match_call(&tree)?;
     let name = match_name(&call.func)?;
+    let collection = match name.value {
+        "tuple" => Collection::Tuple,
+        "list" => Collection::List,
+        "dict" => Collection::Dict,
+        _ => bail!("Expected 'tuple', 'list', or 'dict'"),
+    };
 
     // Arena allocator used to create formatted strings of sufficient lifetime,
     // below.
     let mut arena: Vec<String> = vec![];
 
-    match name.value {
+    match collection {
-        "tuple" => {
+        Collection::Tuple => {
             tree = Expression::Tuple(Box::new(Tuple {
                 elements: vec![],
                 lpar: vec![LeftParen::default()],
                 rpar: vec![RightParen::default()],
             }));
         }
-        "list" => {
+        Collection::List => {
             tree = Expression::List(Box::new(List {
                 elements: vec![],
                 lbracket: LeftSquareBracket::default(),
@@ -396,7 +414,7 @@ pub(crate) fn fix_unnecessary_collection_call(
                 rpar: vec![],
             }));
         }
-        "dict" => {
+        Collection::Dict => {
             if call.args.is_empty() {
                 tree = Expression::Dict(Box::new(Dict {
                     elements: vec![],
@@ -406,16 +424,18 @@ pub(crate) fn fix_unnecessary_collection_call(
                     rpar: vec![],
                 }));
             } else {
+                let quote = checker.f_string_quote_style().unwrap_or(stylist.quote());
+
                 // Quote each argument.
                 for arg in &call.args {
                     let quoted = format!(
                         "{}{}{}",
-                        stylist.quote(),
+                        quote,
                         arg.keyword
                             .as_ref()
                             .expect("Expected dictionary argument to be kwarg")
                             .value,
-                        stylist.quote(),
+                        quote,
                     );
                     arena.push(quoted);
                 }
@@ -457,17 +477,56 @@ pub(crate) fn fix_unnecessary_collection_call(
                 }));
             }
         }
-        _ => {
-            bail!("Expected function name to be one of: 'tuple', 'list', 'dict'");
-        }
     };
 
     Ok(Edit::range_replacement(
-        tree.codegen_stylist(stylist),
+        if matches!(collection, Collection::Dict) {
+            pad_expression(tree.codegen_stylist(stylist), expr.range(), checker)
+        } else {
+            tree.codegen_stylist(stylist)
+        },
         expr.range(),
     ))
 }
 
+/// Re-formats the given expression for use within a formatted string.
+///
+/// For example, when converting a `dict` call to a dictionary literal within
+/// a formatted string, we might naively generate the following code:
+///
+/// ```python
+/// f"{{'a': 1, 'b': 2}}"
+/// ```
+///
+/// However, this is a syntax error under the f-string grammar. As such,
+/// this method will pad the start and end of an expression as needed to
+/// avoid producing invalid syntax.
+fn pad_expression(content: String, range: TextRange, checker: &Checker) -> String {
+    if !checker.semantic_model().in_f_string() {
+        return content;
+    }
+
+    // If the expression is immediately preceded by an opening brace, then
+    // we need to add a space before the expression.
+    let prefix = checker.locator.up_to(range.start());
+    let left_pad = matches!(prefix.chars().rev().next(), Some('{'));
+
+    // If the expression is immediately preceded by an opening brace, then
+    // we need to add a space before the expression.
+    let suffix = checker.locator.after(range.end());
+    let right_pad = matches!(suffix.chars().next(), Some('}'));
+
+    if left_pad && right_pad {
+        format!(" {content} ")
+    } else if left_pad {
+        format!(" {content}")
+    } else if right_pad {
+        format!("{content} ")
+    } else {
+        content
+    }
+}
+
 /// (C409) Convert `tuple([1, 2])` to `tuple(1, 2)`
 pub(crate) fn fix_unnecessary_literal_within_tuple_call(
     locator: &Locator,

crates/ruff/src/rules/flake8_comprehensions/rules/unnecessary_collection_call.rs

@@ -90,9 +90,7 @@ pub(crate) fn unnecessary_collection_call(
     );
     if checker.patch(diagnostic.kind.rule()) {
         #[allow(deprecated)]
-        diagnostic.try_set_fix_from_edit(|| {
+        diagnostic.try_set_fix_from_edit(|| fixes::fix_unnecessary_collection_call(checker, expr));
-            fixes::fix_unnecessary_collection_call(checker.locator, checker.stylist, expr)
-        });
     }
     checker.diagnostics.push(diagnostic);
 }

crates/ruff/src/rules/flake8_comprehensions/rules/unnecessary_generator_dict.rs

@@ -45,7 +45,6 @@ impl AlwaysAutofixableViolation for UnnecessaryGeneratorDict {
 pub(crate) fn unnecessary_generator_dict(
     checker: &mut Checker,
     expr: &Expr,
-    parent: Option<&Expr>,
     func: &Expr,
     args: &[Expr],
     keywords: &[Keyword],
@@ -60,12 +59,7 @@ pub(crate) fn unnecessary_generator_dict(
                 if checker.patch(diagnostic.kind.rule()) {
                     #[allow(deprecated)]
                     diagnostic.try_set_fix_from_edit(|| {
-                        fixes::fix_unnecessary_generator_dict(
+                        fixes::fix_unnecessary_generator_dict(checker, expr)
-                            checker.locator,
-                            checker.stylist,
-                            expr,
-                            parent,
-                        )
                     });
                 }
                 checker.diagnostics.push(diagnostic);

crates/ruff/src/rules/flake8_comprehensions/rules/unnecessary_generator_set.rs

@@ -45,7 +45,6 @@ impl AlwaysAutofixableViolation for UnnecessaryGeneratorSet {
 pub(crate) fn unnecessary_generator_set(
     checker: &mut Checker,
     expr: &Expr,
-    parent: Option<&Expr>,
     func: &Expr,
     args: &[Expr],
     keywords: &[Keyword],
@@ -60,9 +59,8 @@ pub(crate) fn unnecessary_generator_set(
         let mut diagnostic = Diagnostic::new(UnnecessaryGeneratorSet, expr.range());
         if checker.patch(diagnostic.kind.rule()) {
             #[allow(deprecated)]
-            diagnostic.try_set_fix_from_edit(|| {
+            diagnostic
-                fixes::fix_unnecessary_generator_set(checker.locator, checker.stylist, expr, parent)
+                .try_set_fix_from_edit(|| fixes::fix_unnecessary_generator_set(checker, expr));
-            });
         }
         checker.diagnostics.push(diagnostic);
     }

crates/ruff/src/rules/flake8_comprehensions/rules/unnecessary_list_comprehension_dict.rs

@@ -66,7 +66,7 @@ pub(crate) fn unnecessary_list_comprehension_dict(
     if checker.patch(diagnostic.kind.rule()) {
         #[allow(deprecated)]
         diagnostic.try_set_fix_from_edit(|| {
-            fixes::fix_unnecessary_list_comprehension_dict(checker.locator, checker.stylist, expr)
+            fixes::fix_unnecessary_list_comprehension_dict(checker, expr)
         });
     }
     checker.diagnostics.push(diagnostic);

crates/ruff/src/rules/flake8_comprehensions/rules/unnecessary_list_comprehension_set.rs

@@ -58,11 +58,7 @@ pub(crate) fn unnecessary_list_comprehension_set(
         if checker.patch(diagnostic.kind.rule()) {
             #[allow(deprecated)]
             diagnostic.try_set_fix_from_edit(|| {
-                fixes::fix_unnecessary_list_comprehension_set(
+                fixes::fix_unnecessary_list_comprehension_set(checker, expr)
-                    checker.locator,
-                    checker.stylist,
-                    expr,
-                )
             });
         }
         checker.diagnostics.push(diagnostic);

crates/ruff/src/rules/flake8_comprehensions/rules/unnecessary_literal_dict.rs

@@ -80,9 +80,7 @@ pub(crate) fn unnecessary_literal_dict(
     );
     if checker.patch(diagnostic.kind.rule()) {
         #[allow(deprecated)]
-        diagnostic.try_set_fix_from_edit(|| {
+        diagnostic.try_set_fix_from_edit(|| fixes::fix_unnecessary_literal_dict(checker, expr));
-            fixes::fix_unnecessary_literal_dict(checker.locator, checker.stylist, expr)
-        });
     }
     checker.diagnostics.push(diagnostic);
 }

crates/ruff/src/rules/flake8_comprehensions/rules/unnecessary_literal_set.rs

@@ -74,9 +74,7 @@ pub(crate) fn unnecessary_literal_set(
     );
     if checker.patch(diagnostic.kind.rule()) {
         #[allow(deprecated)]
-        diagnostic.try_set_fix_from_edit(|| {
+        diagnostic.try_set_fix_from_edit(|| fixes::fix_unnecessary_literal_set(checker, expr));
-            fixes::fix_unnecessary_literal_set(checker.locator, checker.stylist, expr)
-        });
     }
     checker.diagnostics.push(diagnostic);
 }

crates/ruff/src/rules/flake8_comprehensions/snapshots/ruff__rules__flake8_comprehensions__tests__C401_C401.py.snap

@@ -5,102 +5,251 @@ C401.py:1:5: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
   |
 1 | x = set(x for x in range(3))
   |     ^^^^^^^^^^^^^^^^^^^^^^^^ C401
-2 | x = set(
+2 | x = set(x for x in range(3))
-3 |     x for x in range(3)
+3 | y = f"{set(a if a < 6 else 0  for a in range(3))}"
   |
   = help: Rewrite as a `set` comprehension
 
 ℹ Suggested fix
 1   |-x = set(x for x in range(3))
   1 |+x = {x for x in range(3)}
-2 2 | x = set(
+2 2 | x = set(x for x in range(3))
-3 3 |     x for x in range(3)
+3 3 | y = f"{set(a if a < 6 else 0  for a in range(3))}"
-4 4 | )
+4 4 | _ = "{}".format(set(a if a < 6 else 0 for a in range(3)))
 
 C401.py:2:5: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
   |
 2 | x = set(x for x in range(3))
-3 |   x = set(
+3 | x = set(x for x in range(3))
-  |  _____^
+  |     ^^^^^^^^^^^^^^^^^^^^^^^^ C401
-4 | |     x for x in range(3)
+4 | y = f"{set(a if a < 6 else 0  for a in range(3))}"
-5 | | )
+5 | _ = "{}".format(set(a if a < 6 else 0 for a in range(3)))
-  | |_^ C401
-6 |   y = f'{set(a if a < 6 else 0  for a in range(3))}'
-7 |   _ = '{}'.format(set(a if a < 6 else 0  for a in range(3)))
   |
   = help: Rewrite as a `set` comprehension
 
 ℹ Suggested fix
 1 1 | x = set(x for x in range(3))
-2   |-x = set(
+2   |-x = set(x for x in range(3))
-  2 |+x = {
+  2 |+x = {x for x in range(3)}
-3 3 |     x for x in range(3)
+3 3 | y = f"{set(a if a < 6 else 0  for a in range(3))}"
-4   |-)
+4 4 | _ = "{}".format(set(a if a < 6 else 0 for a in range(3)))
-  4 |+}
+5 5 | print(f"Hello {set(a for a in range(3))} World")
-5 5 | y = f'{set(a if a < 6 else 0  for a in range(3))}'
-6 6 | _ = '{}'.format(set(a if a < 6 else 0  for a in range(3)))
-7 7 | print(f'Hello {set(a for a in range(3))} World')
 
-C401.py:5:8: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
+C401.py:3:8: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
   |
-5 |     x for x in range(3)
+3 | x = set(x for x in range(3))
-6 | )
+4 | x = set(x for x in range(3))
-7 | y = f'{set(a if a < 6 else 0  for a in range(3))}'
+5 | y = f"{set(a if a < 6 else 0  for a in range(3))}"
   |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ C401
-8 | _ = '{}'.format(set(a if a < 6 else 0  for a in range(3)))
+6 | _ = "{}".format(set(a if a < 6 else 0 for a in range(3)))
-9 | print(f'Hello {set(a for a in range(3))} World')
+7 | print(f"Hello {set(a for a in range(3))} World")
   |
   = help: Rewrite as a `set` comprehension
 
 ℹ Suggested fix
-2 2 | x = set(
+1 1 | x = set(x for x in range(3))
-3 3 |     x for x in range(3)
+2 2 | x = set(x for x in range(3))
-4 4 | )
+3   |-y = f"{set(a if a < 6 else 0  for a in range(3))}"
-5   |-y = f'{set(a if a < 6 else 0  for a in range(3))}'
+  3 |+y = f"{ {a if a < 6 else 0  for a in range(3)} }"
-  5 |+y = f'{ {a if a < 6 else 0  for a in range(3)} }'
+4 4 | _ = "{}".format(set(a if a < 6 else 0 for a in range(3)))
-6 6 | _ = '{}'.format(set(a if a < 6 else 0  for a in range(3)))
+5 5 | print(f"Hello {set(a for a in range(3))} World")
-7 7 | print(f'Hello {set(a for a in range(3))} World')
+6 6 | 
-8 8 | 
 
-C401.py:6:17: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
+C401.py:4:17: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
   |
-6 | )
+4 | x = set(x for x in range(3))
-7 | y = f'{set(a if a < 6 else 0  for a in range(3))}'
+5 | y = f"{set(a if a < 6 else 0  for a in range(3))}"
-8 | _ = '{}'.format(set(a if a < 6 else 0  for a in range(3)))
+6 | _ = "{}".format(set(a if a < 6 else 0 for a in range(3)))
-  |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ C401
+  |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ C401
-9 | print(f'Hello {set(a for a in range(3))} World')
+7 | print(f"Hello {set(a for a in range(3))} World")
   |
   = help: Rewrite as a `set` comprehension
 
 ℹ Suggested fix
-3 3 |     x for x in range(3)
+1 1 | x = set(x for x in range(3))
-4 4 | )
+2 2 | x = set(x for x in range(3))
-5 5 | y = f'{set(a if a < 6 else 0  for a in range(3))}'
+3 3 | y = f"{set(a if a < 6 else 0  for a in range(3))}"
-6   |-_ = '{}'.format(set(a if a < 6 else 0  for a in range(3)))
+4   |-_ = "{}".format(set(a if a < 6 else 0 for a in range(3)))
-  6 |+_ = '{}'.format({a if a < 6 else 0  for a in range(3)})
+  4 |+_ = "{}".format({a if a < 6 else 0 for a in range(3)})
-7 7 | print(f'Hello {set(a for a in range(3))} World')
+5 5 | print(f"Hello {set(a for a in range(3))} World")
-8 8 | 
+6 6 | 
-9 9 | def set(*args, **kwargs):
+7 7 | 
 
-C401.py:7:16: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
+C401.py:5:16: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
   |
- 7 | y = f'{set(a if a < 6 else 0  for a in range(3))}'
+5 | y = f"{set(a if a < 6 else 0  for a in range(3))}"
- 8 | _ = '{}'.format(set(a if a < 6 else 0  for a in range(3)))
+6 | _ = "{}".format(set(a if a < 6 else 0 for a in range(3)))
- 9 | print(f'Hello {set(a for a in range(3))} World')
+7 | print(f"Hello {set(a for a in range(3))} World")
   |                ^^^^^^^^^^^^^^^^^^^^^^^^ C401
-10 | 
-11 | def set(*args, **kwargs):
   |
   = help: Rewrite as a `set` comprehension
 
 ℹ Suggested fix
-4 4 | )
+2 2 | x = set(x for x in range(3))
-5 5 | y = f'{set(a if a < 6 else 0  for a in range(3))}'
+3 3 | y = f"{set(a if a < 6 else 0  for a in range(3))}"
-6 6 | _ = '{}'.format(set(a if a < 6 else 0  for a in range(3)))
+4 4 | _ = "{}".format(set(a if a < 6 else 0 for a in range(3)))
-7   |-print(f'Hello {set(a for a in range(3))} World')
+5   |-print(f"Hello {set(a for a in range(3))} World")
-  7 |+print(f'Hello { {a for a in range(3)} } World')
+  5 |+print(f"Hello { {a for a in range(3)} } World")
-8 8 | 
+6 6 | 
-9 9 | def set(*args, **kwargs):
+7 7 | 
-10 10 |     return None
+8 8 | def f(x):
+
+C401.py:12:16: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
+   |
+12 | print(f'Hello {set(a for a in "abc")} World')
+   |                ^^^^^^^^^^^^^^^^^^^^^ C401
+13 | print(f"Hello {set(a for a in 'abc')} World")
+14 | print(f"Hello {set(f(a) for a in 'abc')} World")
+   |
+   = help: Rewrite as a `set` comprehension
+
+ℹ Suggested fix
+9  9  |     return x
+10 10 | 
+11 11 | 
+12    |-print(f'Hello {set(a for a in "abc")} World')
+   12 |+print(f'Hello { {a for a in "abc"} } World')
+13 13 | print(f"Hello {set(a for a in 'abc')} World")
+14 14 | print(f"Hello {set(f(a) for a in 'abc')} World")
+15 15 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+
+C401.py:13:16: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
+   |
+13 | print(f'Hello {set(a for a in "abc")} World')
+14 | print(f"Hello {set(a for a in 'abc')} World")
+   |                ^^^^^^^^^^^^^^^^^^^^^ C401
+15 | print(f"Hello {set(f(a) for a in 'abc')} World")
+16 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+   |
+   = help: Rewrite as a `set` comprehension
+
+ℹ Suggested fix
+10 10 | 
+11 11 | 
+12 12 | print(f'Hello {set(a for a in "abc")} World')
+13    |-print(f"Hello {set(a for a in 'abc')} World")
+   13 |+print(f"Hello { {a for a in 'abc'} } World")
+14 14 | print(f"Hello {set(f(a) for a in 'abc')} World")
+15 15 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+16 16 | print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
+
+C401.py:14:16: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
+   |
+14 | print(f'Hello {set(a for a in "abc")} World')
+15 | print(f"Hello {set(a for a in 'abc')} World")
+16 | print(f"Hello {set(f(a) for a in 'abc')} World")
+   |                ^^^^^^^^^^^^^^^^^^^^^^^^ C401
+17 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+18 | print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
+   |
+   = help: Rewrite as a `set` comprehension
+
+ℹ Suggested fix
+11 11 | 
+12 12 | print(f'Hello {set(a for a in "abc")} World')
+13 13 | print(f"Hello {set(a for a in 'abc')} World")
+14    |-print(f"Hello {set(f(a) for a in 'abc')} World")
+   14 |+print(f"Hello { {f(a) for a in 'abc'} } World")
+15 15 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+16 16 | print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
+17 17 | 
+
+C401.py:15:10: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
+   |
+15 | print(f"Hello {set(a for a in 'abc')} World")
+16 | print(f"Hello {set(f(a) for a in 'abc')} World")
+17 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+   |          ^^^^^^^^^^^^^^^^^^^^^ C401
+18 | print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
+   |
+   = help: Rewrite as a `set` comprehension
+
+ℹ Suggested fix
+12 12 | print(f'Hello {set(a for a in "abc")} World')
+13 13 | print(f"Hello {set(a for a in 'abc')} World")
+14 14 | print(f"Hello {set(f(a) for a in 'abc')} World")
+15    |-print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+   15 |+print(f"{ {a for a in 'abc'} - set(a for a in 'ab')}")
+16 16 | print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
+17 17 | 
+18 18 | # The fix generated for this diagnostic is incorrect, as we add additional space
+
+C401.py:15:34: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
+   |
+15 | print(f"Hello {set(a for a in 'abc')} World")
+16 | print(f"Hello {set(f(a) for a in 'abc')} World")
+17 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+   |                                  ^^^^^^^^^^^^^^^^^^^^ C401
+18 | print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
+   |
+   = help: Rewrite as a `set` comprehension
+
+ℹ Suggested fix
+12 12 | print(f'Hello {set(a for a in "abc")} World')
+13 13 | print(f"Hello {set(a for a in 'abc')} World")
+14 14 | print(f"Hello {set(f(a) for a in 'abc')} World")
+15    |-print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+   15 |+print(f"{set(a for a in 'abc') - {a for a in 'ab'} }")
+16 16 | print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
+17 17 | 
+18 18 | # The fix generated for this diagnostic is incorrect, as we add additional space
+
+C401.py:16:11: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
+   |
+16 | print(f"Hello {set(f(a) for a in 'abc')} World")
+17 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+18 | print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
+   |           ^^^^^^^^^^^^^^^^^^^^^ C401
+19 | 
+20 | # The fix generated for this diagnostic is incorrect, as we add additional space
+   |
+   = help: Rewrite as a `set` comprehension
+
+ℹ Suggested fix
+13 13 | print(f"Hello {set(a for a in 'abc')} World")
+14 14 | print(f"Hello {set(f(a) for a in 'abc')} World")
+15 15 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+16    |-print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
+   16 |+print(f"{ {a for a in 'abc'} - set(a for a in 'ab') }")
+17 17 | 
+18 18 | # The fix generated for this diagnostic is incorrect, as we add additional space
+19 19 | # around the set comprehension.
+
+C401.py:16:35: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
+   |
+16 | print(f"Hello {set(f(a) for a in 'abc')} World")
+17 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+18 | print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
+   |                                   ^^^^^^^^^^^^^^^^^^^^ C401
+19 | 
+20 | # The fix generated for this diagnostic is incorrect, as we add additional space
+   |
+   = help: Rewrite as a `set` comprehension
+
+ℹ Suggested fix
+13 13 | print(f"Hello {set(a for a in 'abc')} World")
+14 14 | print(f"Hello {set(f(a) for a in 'abc')} World")
+15 15 | print(f"{set(a for a in 'abc') - set(a for a in 'ab')}")
+16    |-print(f"{ set(a for a in 'abc') - set(a for a in 'ab') }")
+   16 |+print(f"{ set(a for a in 'abc') - {a for a in 'ab'} }")
+17 17 | 
+18 18 | # The fix generated for this diagnostic is incorrect, as we add additional space
+19 19 | # around the set comprehension.
+
+C401.py:20:12: C401 [*] Unnecessary generator (rewrite as a `set` comprehension)
+   |
+20 | # The fix generated for this diagnostic is incorrect, as we add additional space
+21 | # around the set comprehension.
+22 | print(f"{ {set(a for a in 'abc')} }")
+   |            ^^^^^^^^^^^^^^^^^^^^^ C401
+   |
+   = help: Rewrite as a `set` comprehension
+
+ℹ Suggested fix
+17 17 | 
+18 18 | # The fix generated for this diagnostic is incorrect, as we add additional space
+19 19 | # around the set comprehension.
+20    |-print(f"{ {set(a for a in 'abc')} }")
+   20 |+print(f"{ { {a for a in 'abc'} } }")
 
 

crates/ruff/src/rules/flake8_comprehensions/snapshots/ruff__rules__flake8_comprehensions__tests__C402_C402.py.snap

@@ -48,6 +48,7 @@ C402.py:6:8: C402 [*] Unnecessary generator (rewrite as a `dict` comprehension)
  8 | y = f'{dict((x, x) for x in range(3))}'
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ C402
  9 | print(f'Hello {dict((x, x) for x in range(3))} World')
+10 | print(f"Hello {dict((x, x) for x in 'abc')} World")
    |
    = help: Rewrite as a `dict` comprehension
 
@@ -58,6 +59,8 @@ C402.py:6:8: C402 [*] Unnecessary generator (rewrite as a `dict` comprehension)
 6   |-y = f'{dict((x, x) for x in range(3))}'
   6 |+y = f'{ {x: x for x in range(3)} }'
 7 7 | print(f'Hello {dict((x, x) for x in range(3))} World')
+8 8 | print(f"Hello {dict((x, x) for x in 'abc')} World")
+9 9 | print(f'Hello {dict((x, x) for x in "abc")} World')
 
 C402.py:7:16: C402 [*] Unnecessary generator (rewrite as a `dict` comprehension)
    |
@@ -65,6 +68,8 @@ C402.py:7:16: C402 [*] Unnecessary generator (rewrite as a `dict` comprehension)
  8 | y = f'{dict((x, x) for x in range(3))}'
  9 | print(f'Hello {dict((x, x) for x in range(3))} World')
    |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ C402
+10 | print(f"Hello {dict((x, x) for x in 'abc')} World")
+11 | print(f'Hello {dict((x, x) for x in "abc")} World')
    |
    = help: Rewrite as a `dict` comprehension
 
@@ -74,5 +79,166 @@ C402.py:7:16: C402 [*] Unnecessary generator (rewrite as a `dict` comprehension)
 6 6 | y = f'{dict((x, x) for x in range(3))}'
 7   |-print(f'Hello {dict((x, x) for x in range(3))} World')
   7 |+print(f'Hello { {x: x for x in range(3)} } World')
+8 8 | print(f"Hello {dict((x, x) for x in 'abc')} World")
+9 9 | print(f'Hello {dict((x, x) for x in "abc")} World')
+10 10 | print(f'Hello {dict((x,x) for x in "abc")} World')
+
+C402.py:8:16: C402 [*] Unnecessary generator (rewrite as a `dict` comprehension)
+   |
+ 8 | y = f'{dict((x, x) for x in range(3))}'
+ 9 | print(f'Hello {dict((x, x) for x in range(3))} World')
+10 | print(f"Hello {dict((x, x) for x in 'abc')} World")
+   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^ C402
+11 | print(f'Hello {dict((x, x) for x in "abc")} World')
+12 | print(f'Hello {dict((x,x) for x in "abc")} World')
+   |
+   = help: Rewrite as a `dict` comprehension
+
+ℹ Suggested fix
+5 5 | dict(((x, x) for x in range(3)), z=3)
+6 6 | y = f'{dict((x, x) for x in range(3))}'
+7 7 | print(f'Hello {dict((x, x) for x in range(3))} World')
+8   |-print(f"Hello {dict((x, x) for x in 'abc')} World")
+  8 |+print(f"Hello { {x: x for x in 'abc'} } World")
+9 9 | print(f'Hello {dict((x, x) for x in "abc")} World')
+10 10 | print(f'Hello {dict((x,x) for x in "abc")} World')
+11 11 | 
+
+C402.py:9:16: C402 [*] Unnecessary generator (rewrite as a `dict` comprehension)
+   |
+ 9 | print(f'Hello {dict((x, x) for x in range(3))} World')
+10 | print(f"Hello {dict((x, x) for x in 'abc')} World")
+11 | print(f'Hello {dict((x, x) for x in "abc")} World')
+   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^ C402
+12 | print(f'Hello {dict((x,x) for x in "abc")} World')
+   |
+   = help: Rewrite as a `dict` comprehension
+
+ℹ Suggested fix
+6  6  | y = f'{dict((x, x) for x in range(3))}'
+7  7  | print(f'Hello {dict((x, x) for x in range(3))} World')
+8  8  | print(f"Hello {dict((x, x) for x in 'abc')} World")
+9     |-print(f'Hello {dict((x, x) for x in "abc")} World')
+   9  |+print(f'Hello { {x: x for x in "abc"} } World')
+10 10 | print(f'Hello {dict((x,x) for x in "abc")} World')
+11 11 | 
+12 12 | f'{dict((x, x) for x in range(3)) | dict((x, x) for x in range(3))}'
+
+C402.py:10:16: C402 [*] Unnecessary generator (rewrite as a `dict` comprehension)
+   |
+10 | print(f"Hello {dict((x, x) for x in 'abc')} World")
+11 | print(f'Hello {dict((x, x) for x in "abc")} World')
+12 | print(f'Hello {dict((x,x) for x in "abc")} World')
+   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^ C402
+13 | 
+14 | f'{dict((x, x) for x in range(3)) | dict((x, x) for x in range(3))}'
+   |
+   = help: Rewrite as a `dict` comprehension
+
+ℹ Suggested fix
+7  7  | print(f'Hello {dict((x, x) for x in range(3))} World')
+8  8  | print(f"Hello {dict((x, x) for x in 'abc')} World")
+9  9  | print(f'Hello {dict((x, x) for x in "abc")} World')
+10    |-print(f'Hello {dict((x,x) for x in "abc")} World')
+   10 |+print(f'Hello { {x: x for x in "abc"} } World')
+11 11 | 
+12 12 | f'{dict((x, x) for x in range(3)) | dict((x, x) for x in range(3))}'
+13 13 | f'{ dict((x, x) for x in range(3)) | dict((x, x) for x in range(3)) }'
+
+C402.py:12:4: C402 [*] Unnecessary generator (rewrite as a `dict` comprehension)
+   |
+12 | print(f'Hello {dict((x,x) for x in "abc")} World')
+13 | 
+14 | f'{dict((x, x) for x in range(3)) | dict((x, x) for x in range(3))}'
+   |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ C402
+15 | f'{ dict((x, x) for x in range(3)) | dict((x, x) for x in range(3)) }'
+   |
+   = help: Rewrite as a `dict` comprehension
+
+ℹ Suggested fix
+9  9  | print(f'Hello {dict((x, x) for x in "abc")} World')
+10 10 | print(f'Hello {dict((x,x) for x in "abc")} World')
+11 11 | 
+12    |-f'{dict((x, x) for x in range(3)) | dict((x, x) for x in range(3))}'
+   12 |+f'{ {x: x for x in range(3)} | dict((x, x) for x in range(3))}'
+13 13 | f'{ dict((x, x) for x in range(3)) | dict((x, x) for x in range(3)) }'
+14 14 | 
+15 15 | def f(x):
+
+C402.py:12:37: C402 [*] Unnecessary generator (rewrite as a `dict` comprehension)
+   |
+12 | print(f'Hello {dict((x,x) for x in "abc")} World')
+13 | 
+14 | f'{dict((x, x) for x in range(3)) | dict((x, x) for x in range(3))}'
+   |                                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ C402
+15 | f'{ dict((x, x) for x in range(3)) | dict((x, x) for x in range(3)) }'
+   |
+   = help: Rewrite as a `dict` comprehension
+
+ℹ Suggested fix
+9  9  | print(f'Hello {dict((x, x) for x in "abc")} World')
+10 10 | print(f'Hello {dict((x,x) for x in "abc")} World')
+11 11 | 
+12    |-f'{dict((x, x) for x in range(3)) | dict((x, x) for x in range(3))}'
+   12 |+f'{dict((x, x) for x in range(3)) | {x: x for x in range(3)} }'
+13 13 | f'{ dict((x, x) for x in range(3)) | dict((x, x) for x in range(3)) }'
+14 14 | 
+15 15 | def f(x):
+
+C402.py:13:5: C402 [*] Unnecessary generator (rewrite as a `dict` comprehension)
+   |
+13 | f'{dict((x, x) for x in range(3)) | dict((x, x) for x in range(3))}'
+14 | f'{ dict((x, x) for x in range(3)) | dict((x, x) for x in range(3)) }'
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ C402
+15 | 
+16 | def f(x):
+   |
+   = help: Rewrite as a `dict` comprehension
+
+ℹ Suggested fix
+10 10 | print(f'Hello {dict((x,x) for x in "abc")} World')
+11 11 | 
+12 12 | f'{dict((x, x) for x in range(3)) | dict((x, x) for x in range(3))}'
+13    |-f'{ dict((x, x) for x in range(3)) | dict((x, x) for x in range(3)) }'
+   13 |+f'{ {x: x for x in range(3)} | dict((x, x) for x in range(3)) }'
+14 14 | 
+15 15 | def f(x):
+16 16 |     return x
+
+C402.py:13:38: C402 [*] Unnecessary generator (rewrite as a `dict` comprehension)
+   |
+13 | f'{dict((x, x) for x in range(3)) | dict((x, x) for x in range(3))}'
+14 | f'{ dict((x, x) for x in range(3)) | dict((x, x) for x in range(3)) }'
+   |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ C402
+15 | 
+16 | def f(x):
+   |
+   = help: Rewrite as a `dict` comprehension
+
+ℹ Suggested fix
+10 10 | print(f'Hello {dict((x,x) for x in "abc")} World')
+11 11 | 
+12 12 | f'{dict((x, x) for x in range(3)) | dict((x, x) for x in range(3))}'
+13    |-f'{ dict((x, x) for x in range(3)) | dict((x, x) for x in range(3)) }'
+   13 |+f'{ dict((x, x) for x in range(3)) | {x: x for x in range(3)} }'
+14 14 | 
+15 15 | def f(x):
+16 16 |     return x
+
+C402.py:18:16: C402 [*] Unnecessary generator (rewrite as a `dict` comprehension)
+   |
+18 |     return x
+19 | 
+20 | print(f'Hello {dict((x,f(x)) for x in "abc")} World')
+   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ C402
+   |
+   = help: Rewrite as a `dict` comprehension
+
+ℹ Suggested fix
+15 15 | def f(x):
+16 16 |     return x
+17 17 | 
+18    |-print(f'Hello {dict((x,f(x)) for x in "abc")} World')
+   18 |+print(f'Hello { {x: f(x) for x in "abc"} } World')
 
 

crates/ruff/src/rules/flake8_comprehensions/snapshots/ruff__rules__flake8_comprehensions__tests__C403_C403.py.snap

@@ -25,6 +25,8 @@ C403.py:2:5: C403 [*] Unnecessary `list` comprehension (rewrite as a `set` compr
 4 | |     [x for x in range(3)]
 5 | | )
   | |_^ C403
+6 |   
+7 |   s = f"{set([x for x in 'ab'])}"
   |
   = help: Rewrite as a `set` comprehension
 
@@ -36,5 +38,135 @@ C403.py:2:5: C403 [*] Unnecessary `list` comprehension (rewrite as a `set` compr
   2 |+s = {
   3 |+    x for x in range(3)
   4 |+}
+5 5 | 
+6 6 | s = f"{set([x for x in 'ab'])}"
+7 7 | s = f'{set([x for x in "ab"])}'
+
+C403.py:6:8: C403 [*] Unnecessary `list` comprehension (rewrite as a `set` comprehension)
+  |
+6 | )
+7 | 
+8 | s = f"{set([x for x in 'ab'])}"
+  |        ^^^^^^^^^^^^^^^^^^^^^^ C403
+9 | s = f'{set([x for x in "ab"])}'
+  |
+  = help: Rewrite as a `set` comprehension
+
+ℹ Suggested fix
+3 3 |     [x for x in range(3)]
+4 4 | )
+5 5 | 
+6   |-s = f"{set([x for x in 'ab'])}"
+  6 |+s = f"{ {x for x in 'ab'} }"
+7 7 | s = f'{set([x for x in "ab"])}'
+8 8 | 
+9 9 | def f(x):
+
+C403.py:7:8: C403 [*] Unnecessary `list` comprehension (rewrite as a `set` comprehension)
+   |
+ 7 | s = f"{set([x for x in 'ab'])}"
+ 8 | s = f'{set([x for x in "ab"])}'
+   |        ^^^^^^^^^^^^^^^^^^^^^^ C403
+ 9 | 
+10 | def f(x):
+   |
+   = help: Rewrite as a `set` comprehension
+
+ℹ Suggested fix
+4 4 | )
+5 5 | 
+6 6 | s = f"{set([x for x in 'ab'])}"
+7   |-s = f'{set([x for x in "ab"])}'
+  7 |+s = f'{ {x for x in "ab"} }'
+8 8 | 
+9 9 | def f(x):
+10 10 |     return x
+
+C403.py:12:8: C403 [*] Unnecessary `list` comprehension (rewrite as a `set` comprehension)
+   |
+12 |     return x
+13 | 
+14 | s = f"{set([f(x) for x in 'ab'])}"
+   |        ^^^^^^^^^^^^^^^^^^^^^^^^^ C403
+15 | 
+16 | s = f"{ set([x for x in 'ab']) | set([x for x in 'ab']) }"
+   |
+   = help: Rewrite as a `set` comprehension
+
+ℹ Suggested fix
+9  9  | def f(x):
+10 10 |     return x
+11 11 | 
+12    |-s = f"{set([f(x) for x in 'ab'])}"
+   12 |+s = f"{ {f(x) for x in 'ab'} }"
+13 13 | 
+14 14 | s = f"{ set([x for x in 'ab']) | set([x for x in 'ab']) }"
+15 15 | s = f"{set([x for x in 'ab']) | set([x for x in 'ab'])}"
+
+C403.py:14:9: C403 [*] Unnecessary `list` comprehension (rewrite as a `set` comprehension)
+   |
+14 | s = f"{set([f(x) for x in 'ab'])}"
+15 | 
+16 | s = f"{ set([x for x in 'ab']) | set([x for x in 'ab']) }"
+   |         ^^^^^^^^^^^^^^^^^^^^^^ C403
+17 | s = f"{set([x for x in 'ab']) | set([x for x in 'ab'])}"
+   |
+   = help: Rewrite as a `set` comprehension
+
+ℹ Suggested fix
+11 11 | 
+12 12 | s = f"{set([f(x) for x in 'ab'])}"
+13 13 | 
+14    |-s = f"{ set([x for x in 'ab']) | set([x for x in 'ab']) }"
+   14 |+s = f"{ {x for x in 'ab'} | set([x for x in 'ab']) }"
+15 15 | s = f"{set([x for x in 'ab']) | set([x for x in 'ab'])}"
+
+C403.py:14:34: C403 [*] Unnecessary `list` comprehension (rewrite as a `set` comprehension)
+   |
+14 | s = f"{set([f(x) for x in 'ab'])}"
+15 | 
+16 | s = f"{ set([x for x in 'ab']) | set([x for x in 'ab']) }"
+   |                                  ^^^^^^^^^^^^^^^^^^^^^^ C403
+17 | s = f"{set([x for x in 'ab']) | set([x for x in 'ab'])}"
+   |
+   = help: Rewrite as a `set` comprehension
+
+ℹ Suggested fix
+11 11 | 
+12 12 | s = f"{set([f(x) for x in 'ab'])}"
+13 13 | 
+14    |-s = f"{ set([x for x in 'ab']) | set([x for x in 'ab']) }"
+   14 |+s = f"{ set([x for x in 'ab']) | {x for x in 'ab'} }"
+15 15 | s = f"{set([x for x in 'ab']) | set([x for x in 'ab'])}"
+
+C403.py:15:8: C403 [*] Unnecessary `list` comprehension (rewrite as a `set` comprehension)
+   |
+15 | s = f"{ set([x for x in 'ab']) | set([x for x in 'ab']) }"
+16 | s = f"{set([x for x in 'ab']) | set([x for x in 'ab'])}"
+   |        ^^^^^^^^^^^^^^^^^^^^^^ C403
+   |
+   = help: Rewrite as a `set` comprehension
+
+ℹ Suggested fix
+12 12 | s = f"{set([f(x) for x in 'ab'])}"
+13 13 | 
+14 14 | s = f"{ set([x for x in 'ab']) | set([x for x in 'ab']) }"
+15    |-s = f"{set([x for x in 'ab']) | set([x for x in 'ab'])}"
+   15 |+s = f"{ {x for x in 'ab'} | set([x for x in 'ab'])}"
+
+C403.py:15:33: C403 [*] Unnecessary `list` comprehension (rewrite as a `set` comprehension)
+   |
+15 | s = f"{ set([x for x in 'ab']) | set([x for x in 'ab']) }"
+16 | s = f"{set([x for x in 'ab']) | set([x for x in 'ab'])}"
+   |                                 ^^^^^^^^^^^^^^^^^^^^^^ C403
+   |
+   = help: Rewrite as a `set` comprehension
+
+ℹ Suggested fix
+12 12 | s = f"{set([f(x) for x in 'ab'])}"
+13 13 | 
+14 14 | s = f"{ set([x for x in 'ab']) | set([x for x in 'ab']) }"
+15    |-s = f"{set([x for x in 'ab']) | set([x for x in 'ab'])}"
+   15 |+s = f"{set([x for x in 'ab']) | {x for x in 'ab'} }"
 
 

crates/ruff/src/rules/flake8_comprehensions/snapshots/ruff__rules__flake8_comprehensions__tests__C404_C404.py.snap

@@ -13,5 +13,155 @@ C404.py:1:1: C404 [*] Unnecessary `list` comprehension (rewrite as a `dict` comp
 1   |-dict([(i, i) for i in range(3)])
   1 |+{i: i for i in range(3)}
 2 2 | dict([(i, i) for i in range(3)], z=4)
+3 3 | 
+4 4 | def f(x):
+
+C404.py:7:4: C404 [*] Unnecessary `list` comprehension (rewrite as a `dict` comprehension)
+   |
+ 7 |     return x
+ 8 | 
+ 9 | f'{dict([(s,s) for s in "ab"])}'
+   |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^ C404
+10 | f"{dict([(s,s) for s in 'ab'])}"
+11 | f"{dict([(s, s) for s in 'ab'])}"
+   |
+   = help: Rewrite as a `dict` comprehension
+
+ℹ Suggested fix
+4 4 | def f(x):
+5 5 |     return x
+6 6 | 
+7   |-f'{dict([(s,s) for s in "ab"])}'
+  7 |+f'{ {s: s for s in "ab"} }'
+8 8 | f"{dict([(s,s) for s in 'ab'])}"
+9 9 | f"{dict([(s, s) for s in 'ab'])}"
+10 10 | f"{dict([(s,f(s)) for s in 'ab'])}"
+
+C404.py:8:4: C404 [*] Unnecessary `list` comprehension (rewrite as a `dict` comprehension)
+   |
+ 8 | f'{dict([(s,s) for s in "ab"])}'
+ 9 | f"{dict([(s,s) for s in 'ab'])}"
+   |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^ C404
+10 | f"{dict([(s, s) for s in 'ab'])}"
+11 | f"{dict([(s,f(s)) for s in 'ab'])}"
+   |
+   = help: Rewrite as a `dict` comprehension
+
+ℹ Suggested fix
+5 5 |     return x
+6 6 | 
+7 7 | f'{dict([(s,s) for s in "ab"])}'
+8   |-f"{dict([(s,s) for s in 'ab'])}"
+  8 |+f"{ {s: s for s in 'ab'} }"
+9 9 | f"{dict([(s, s) for s in 'ab'])}"
+10 10 | f"{dict([(s,f(s)) for s in 'ab'])}"
+11 11 | 
+
+C404.py:9:4: C404 [*] Unnecessary `list` comprehension (rewrite as a `dict` comprehension)
+   |
+ 9 | f'{dict([(s,s) for s in "ab"])}'
+10 | f"{dict([(s,s) for s in 'ab'])}"
+11 | f"{dict([(s, s) for s in 'ab'])}"
+   |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ C404
+12 | f"{dict([(s,f(s)) for s in 'ab'])}"
+   |
+   = help: Rewrite as a `dict` comprehension
+
+ℹ Suggested fix
+6  6  | 
+7  7  | f'{dict([(s,s) for s in "ab"])}'
+8  8  | f"{dict([(s,s) for s in 'ab'])}"
+9     |-f"{dict([(s, s) for s in 'ab'])}"
+   9  |+f"{ {s: s for s in 'ab'} }"
+10 10 | f"{dict([(s,f(s)) for s in 'ab'])}"
+11 11 | 
+12 12 | f'{dict([(s,s) for s in "ab"]) | dict([(s,s) for s in "ab"])}'
+
+C404.py:10:4: C404 [*] Unnecessary `list` comprehension (rewrite as a `dict` comprehension)
+   |
+10 | f"{dict([(s,s) for s in 'ab'])}"
+11 | f"{dict([(s, s) for s in 'ab'])}"
+12 | f"{dict([(s,f(s)) for s in 'ab'])}"
+   |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ C404
+13 | 
+14 | f'{dict([(s,s) for s in "ab"]) | dict([(s,s) for s in "ab"])}'
+   |
+   = help: Rewrite as a `dict` comprehension
+
+ℹ Suggested fix
+7  7  | f'{dict([(s,s) for s in "ab"])}'
+8  8  | f"{dict([(s,s) for s in 'ab'])}"
+9  9  | f"{dict([(s, s) for s in 'ab'])}"
+10    |-f"{dict([(s,f(s)) for s in 'ab'])}"
+   10 |+f"{ {s: f(s) for s in 'ab'} }"
+11 11 | 
+12 12 | f'{dict([(s,s) for s in "ab"]) | dict([(s,s) for s in "ab"])}'
+13 13 | f'{ dict([(s,s) for s in "ab"]) | dict([(s,s) for s in "ab"]) }'
+
+C404.py:12:4: C404 [*] Unnecessary `list` comprehension (rewrite as a `dict` comprehension)
+   |
+12 | f"{dict([(s,f(s)) for s in 'ab'])}"
+13 | 
+14 | f'{dict([(s,s) for s in "ab"]) | dict([(s,s) for s in "ab"])}'
+   |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^ C404
+15 | f'{ dict([(s,s) for s in "ab"]) | dict([(s,s) for s in "ab"]) }'
+   |
+   = help: Rewrite as a `dict` comprehension
+
+ℹ Suggested fix
+9  9  | f"{dict([(s, s) for s in 'ab'])}"
+10 10 | f"{dict([(s,f(s)) for s in 'ab'])}"
+11 11 | 
+12    |-f'{dict([(s,s) for s in "ab"]) | dict([(s,s) for s in "ab"])}'
+   12 |+f'{ {s: s for s in "ab"} | dict([(s,s) for s in "ab"])}'
+13 13 | f'{ dict([(s,s) for s in "ab"]) | dict([(s,s) for s in "ab"]) }'
+
+C404.py:12:34: C404 [*] Unnecessary `list` comprehension (rewrite as a `dict` comprehension)
+   |
+12 | f"{dict([(s,f(s)) for s in 'ab'])}"
+13 | 
+14 | f'{dict([(s,s) for s in "ab"]) | dict([(s,s) for s in "ab"])}'
+   |                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^ C404
+15 | f'{ dict([(s,s) for s in "ab"]) | dict([(s,s) for s in "ab"]) }'
+   |
+   = help: Rewrite as a `dict` comprehension
+
+ℹ Suggested fix
+9  9  | f"{dict([(s, s) for s in 'ab'])}"
+10 10 | f"{dict([(s,f(s)) for s in 'ab'])}"
+11 11 | 
+12    |-f'{dict([(s,s) for s in "ab"]) | dict([(s,s) for s in "ab"])}'
+   12 |+f'{dict([(s,s) for s in "ab"]) | {s: s for s in "ab"} }'
+13 13 | f'{ dict([(s,s) for s in "ab"]) | dict([(s,s) for s in "ab"]) }'
+
+C404.py:13:5: C404 [*] Unnecessary `list` comprehension (rewrite as a `dict` comprehension)
+   |
+13 | f'{dict([(s,s) for s in "ab"]) | dict([(s,s) for s in "ab"])}'
+14 | f'{ dict([(s,s) for s in "ab"]) | dict([(s,s) for s in "ab"]) }'
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ C404
+   |
+   = help: Rewrite as a `dict` comprehension
+
+ℹ Suggested fix
+10 10 | f"{dict([(s,f(s)) for s in 'ab'])}"
+11 11 | 
+12 12 | f'{dict([(s,s) for s in "ab"]) | dict([(s,s) for s in "ab"])}'
+13    |-f'{ dict([(s,s) for s in "ab"]) | dict([(s,s) for s in "ab"]) }'
+   13 |+f'{ {s: s for s in "ab"} | dict([(s,s) for s in "ab"]) }'
+
+C404.py:13:35: C404 [*] Unnecessary `list` comprehension (rewrite as a `dict` comprehension)
+   |
+13 | f'{dict([(s,s) for s in "ab"]) | dict([(s,s) for s in "ab"])}'
+14 | f'{ dict([(s,s) for s in "ab"]) | dict([(s,s) for s in "ab"]) }'
+   |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^ C404
+   |
+   = help: Rewrite as a `dict` comprehension
+
+ℹ Suggested fix
+10 10 | f"{dict([(s,f(s)) for s in 'ab'])}"
+11 11 | 
+12 12 | f'{dict([(s,s) for s in "ab"]) | dict([(s,s) for s in "ab"])}'
+13    |-f'{ dict([(s,s) for s in "ab"]) | dict([(s,s) for s in "ab"]) }'
+   13 |+f'{ dict([(s,s) for s in "ab"]) | {s: s for s in "ab"} }'
 
 

crates/ruff/src/rules/flake8_comprehensions/snapshots/ruff__rules__flake8_comprehensions__tests__C405_C405.py.snap

@@ -183,6 +183,8 @@ C405.py:16:1: C405 [*] Unnecessary `list` literal (rewrite as a `set` literal)
 19 | |     [1,]
 20 | | )
    | |_^ C405
+21 |   f"{set([1,2,3])}"
+22 |   f"{set(['a', 'b'])}"
    |
    = help: Rewrite as a `set` literal
 
@@ -194,5 +196,218 @@ C405.py:16:1: C405 [*] Unnecessary `list` literal (rewrite as a `set` literal)
 17    |-    [1,]
 18    |-)
    16 |+{1,}
+19 17 | f"{set([1,2,3])}"
+20 18 | f"{set(['a', 'b'])}"
+21 19 | f'{set(["a", "b"])}'
+
+C405.py:19:4: C405 [*] Unnecessary `list` literal (rewrite as a `set` literal)
+   |
+19 |     [1,]
+20 | )
+21 | f"{set([1,2,3])}"
+   |    ^^^^^^^^^^^^ C405
+22 | f"{set(['a', 'b'])}"
+23 | f'{set(["a", "b"])}'
+   |
+   = help: Rewrite as a `set` literal
+
+ℹ Suggested fix
+16 16 | set(
+17 17 |     [1,]
+18 18 | )
+19    |-f"{set([1,2,3])}"
+   19 |+f"{ {1,2,3} }"
+20 20 | f"{set(['a', 'b'])}"
+21 21 | f'{set(["a", "b"])}'
+22 22 | 
+
+C405.py:20:4: C405 [*] Unnecessary `list` literal (rewrite as a `set` literal)
+   |
+20 | )
+21 | f"{set([1,2,3])}"
+22 | f"{set(['a', 'b'])}"
+   |    ^^^^^^^^^^^^^^^ C405
+23 | f'{set(["a", "b"])}'
+   |
+   = help: Rewrite as a `set` literal
+
+ℹ Suggested fix
+17 17 |     [1,]
+18 18 | )
+19 19 | f"{set([1,2,3])}"
+20    |-f"{set(['a', 'b'])}"
+   20 |+f"{ {'a', 'b'} }"
+21 21 | f'{set(["a", "b"])}'
+22 22 | 
+23 23 | f"{set(['a', 'b']) - set(['a'])}"
+
+C405.py:21:4: C405 [*] Unnecessary `list` literal (rewrite as a `set` literal)
+   |
+21 | f"{set([1,2,3])}"
+22 | f"{set(['a', 'b'])}"
+23 | f'{set(["a", "b"])}'
+   |    ^^^^^^^^^^^^^^^ C405
+24 | 
+25 | f"{set(['a', 'b']) - set(['a'])}"
+   |
+   = help: Rewrite as a `set` literal
+
+ℹ Suggested fix
+18 18 | )
+19 19 | f"{set([1,2,3])}"
+20 20 | f"{set(['a', 'b'])}"
+21    |-f'{set(["a", "b"])}'
+   21 |+f'{ {"a", "b"} }'
+22 22 | 
+23 23 | f"{set(['a', 'b']) - set(['a'])}"
+24 24 | f"{ set(['a', 'b']) - set(['a']) }"
+
+C405.py:23:4: C405 [*] Unnecessary `list` literal (rewrite as a `set` literal)
+   |
+23 | f'{set(["a", "b"])}'
+24 | 
+25 | f"{set(['a', 'b']) - set(['a'])}"
+   |    ^^^^^^^^^^^^^^^ C405
+26 | f"{ set(['a', 'b']) - set(['a']) }"
+27 | f"a {set(['a', 'b']) - set(['a'])} b"
+   |
+   = help: Rewrite as a `set` literal
+
+ℹ Suggested fix
+20 20 | f"{set(['a', 'b'])}"
+21 21 | f'{set(["a", "b"])}'
+22 22 | 
+23    |-f"{set(['a', 'b']) - set(['a'])}"
+   23 |+f"{ {'a', 'b'} - set(['a'])}"
+24 24 | f"{ set(['a', 'b']) - set(['a']) }"
+25 25 | f"a {set(['a', 'b']) - set(['a'])} b"
+26 26 | f"a { set(['a', 'b']) - set(['a']) } b"
+
+C405.py:23:22: C405 [*] Unnecessary `list` literal (rewrite as a `set` literal)
+   |
+23 | f'{set(["a", "b"])}'
+24 | 
+25 | f"{set(['a', 'b']) - set(['a'])}"
+   |                      ^^^^^^^^^^ C405
+26 | f"{ set(['a', 'b']) - set(['a']) }"
+27 | f"a {set(['a', 'b']) - set(['a'])} b"
+   |
+   = help: Rewrite as a `set` literal
+
+ℹ Suggested fix
+20 20 | f"{set(['a', 'b'])}"
+21 21 | f'{set(["a", "b"])}'
+22 22 | 
+23    |-f"{set(['a', 'b']) - set(['a'])}"
+   23 |+f"{set(['a', 'b']) - {'a'} }"
+24 24 | f"{ set(['a', 'b']) - set(['a']) }"
+25 25 | f"a {set(['a', 'b']) - set(['a'])} b"
+26 26 | f"a { set(['a', 'b']) - set(['a']) } b"
+
+C405.py:24:5: C405 [*] Unnecessary `list` literal (rewrite as a `set` literal)
+   |
+24 | f"{set(['a', 'b']) - set(['a'])}"
+25 | f"{ set(['a', 'b']) - set(['a']) }"
+   |     ^^^^^^^^^^^^^^^ C405
+26 | f"a {set(['a', 'b']) - set(['a'])} b"
+27 | f"a { set(['a', 'b']) - set(['a']) } b"
+   |
+   = help: Rewrite as a `set` literal
+
+ℹ Suggested fix
+21 21 | f'{set(["a", "b"])}'
+22 22 | 
+23 23 | f"{set(['a', 'b']) - set(['a'])}"
+24    |-f"{ set(['a', 'b']) - set(['a']) }"
+   24 |+f"{ {'a', 'b'} - set(['a']) }"
+25 25 | f"a {set(['a', 'b']) - set(['a'])} b"
+26 26 | f"a { set(['a', 'b']) - set(['a']) } b"
+
+C405.py:24:23: C405 [*] Unnecessary `list` literal (rewrite as a `set` literal)
+   |
+24 | f"{set(['a', 'b']) - set(['a'])}"
+25 | f"{ set(['a', 'b']) - set(['a']) }"
+   |                       ^^^^^^^^^^ C405
+26 | f"a {set(['a', 'b']) - set(['a'])} b"
+27 | f"a { set(['a', 'b']) - set(['a']) } b"
+   |
+   = help: Rewrite as a `set` literal
+
+ℹ Suggested fix
+21 21 | f'{set(["a", "b"])}'
+22 22 | 
+23 23 | f"{set(['a', 'b']) - set(['a'])}"
+24    |-f"{ set(['a', 'b']) - set(['a']) }"
+   24 |+f"{ set(['a', 'b']) - {'a'} }"
+25 25 | f"a {set(['a', 'b']) - set(['a'])} b"
+26 26 | f"a { set(['a', 'b']) - set(['a']) } b"
+
+C405.py:25:6: C405 [*] Unnecessary `list` literal (rewrite as a `set` literal)
+   |
+25 | f"{set(['a', 'b']) - set(['a'])}"
+26 | f"{ set(['a', 'b']) - set(['a']) }"
+27 | f"a {set(['a', 'b']) - set(['a'])} b"
+   |      ^^^^^^^^^^^^^^^ C405
+28 | f"a { set(['a', 'b']) - set(['a']) } b"
+   |
+   = help: Rewrite as a `set` literal
+
+ℹ Suggested fix
+22 22 | 
+23 23 | f"{set(['a', 'b']) - set(['a'])}"
+24 24 | f"{ set(['a', 'b']) - set(['a']) }"
+25    |-f"a {set(['a', 'b']) - set(['a'])} b"
+   25 |+f"a { {'a', 'b'} - set(['a'])} b"
+26 26 | f"a { set(['a', 'b']) - set(['a']) } b"
+
+C405.py:25:24: C405 [*] Unnecessary `list` literal (rewrite as a `set` literal)
+   |
+25 | f"{set(['a', 'b']) - set(['a'])}"
+26 | f"{ set(['a', 'b']) - set(['a']) }"
+27 | f"a {set(['a', 'b']) - set(['a'])} b"
+   |                        ^^^^^^^^^^ C405
+28 | f"a { set(['a', 'b']) - set(['a']) } b"
+   |
+   = help: Rewrite as a `set` literal
+
+ℹ Suggested fix
+22 22 | 
+23 23 | f"{set(['a', 'b']) - set(['a'])}"
+24 24 | f"{ set(['a', 'b']) - set(['a']) }"
+25    |-f"a {set(['a', 'b']) - set(['a'])} b"
+   25 |+f"a {set(['a', 'b']) - {'a'} } b"
+26 26 | f"a { set(['a', 'b']) - set(['a']) } b"
+
+C405.py:26:7: C405 [*] Unnecessary `list` literal (rewrite as a `set` literal)
+   |
+26 | f"{ set(['a', 'b']) - set(['a']) }"
+27 | f"a {set(['a', 'b']) - set(['a'])} b"
+28 | f"a { set(['a', 'b']) - set(['a']) } b"
+   |       ^^^^^^^^^^^^^^^ C405
+   |
+   = help: Rewrite as a `set` literal
+
+ℹ Suggested fix
+23 23 | f"{set(['a', 'b']) - set(['a'])}"
+24 24 | f"{ set(['a', 'b']) - set(['a']) }"
+25 25 | f"a {set(['a', 'b']) - set(['a'])} b"
+26    |-f"a { set(['a', 'b']) - set(['a']) } b"
+   26 |+f"a { {'a', 'b'} - set(['a']) } b"
+
+C405.py:26:25: C405 [*] Unnecessary `list` literal (rewrite as a `set` literal)
+   |
+26 | f"{ set(['a', 'b']) - set(['a']) }"
+27 | f"a {set(['a', 'b']) - set(['a'])} b"
+28 | f"a { set(['a', 'b']) - set(['a']) } b"
+   |                         ^^^^^^^^^^ C405
+   |
+   = help: Rewrite as a `set` literal
+
+ℹ Suggested fix
+23 23 | f"{set(['a', 'b']) - set(['a'])}"
+24 24 | f"{ set(['a', 'b']) - set(['a']) }"
+25 25 | f"a {set(['a', 'b']) - set(['a'])} b"
+26    |-f"a { set(['a', 'b']) - set(['a']) } b"
+   26 |+f"a { set(['a', 'b']) - {'a'} } b"
 
 

crates/ruff/src/rules/flake8_comprehensions/snapshots/ruff__rules__flake8_comprehensions__tests__C408_C408.py.snap

@@ -75,4 +75,234 @@ C408.py:4:6: C408 [*] Unnecessary `dict` call (rewrite as a literal)
 6 6 | 
 7 7 | 
 
+C408.py:14:4: C408 [*] Unnecessary `dict` call (rewrite as a literal)
+   |
+14 | a = list()
+15 | 
+16 | f"{dict(x='y')}"
+   |    ^^^^^^^^^^^ C408
+17 | f'{dict(x="y")}'
+18 | f"{dict()}"
+   |
+   = help: Rewrite as a literal
+
+ℹ Suggested fix
+11 11 | 
+12 12 | a = list()
+13 13 | 
+14    |-f"{dict(x='y')}"
+   14 |+f"{ {'x': 'y'} }"
+15 15 | f'{dict(x="y")}'
+16 16 | f"{dict()}"
+17 17 | f"a {dict()} b"
+
+C408.py:15:4: C408 [*] Unnecessary `dict` call (rewrite as a literal)
+   |
+15 | f"{dict(x='y')}"
+16 | f'{dict(x="y")}'
+   |    ^^^^^^^^^^^ C408
+17 | f"{dict()}"
+18 | f"a {dict()} b"
+   |
+   = help: Rewrite as a literal
+
+ℹ Suggested fix
+12 12 | a = list()
+13 13 | 
+14 14 | f"{dict(x='y')}"
+15    |-f'{dict(x="y")}'
+   15 |+f'{ {"x": "y"} }'
+16 16 | f"{dict()}"
+17 17 | f"a {dict()} b"
+18 18 | 
+
+C408.py:16:4: C408 [*] Unnecessary `dict` call (rewrite as a literal)
+   |
+16 | f"{dict(x='y')}"
+17 | f'{dict(x="y")}'
+18 | f"{dict()}"
+   |    ^^^^^^ C408
+19 | f"a {dict()} b"
+   |
+   = help: Rewrite as a literal
+
+ℹ Suggested fix
+13 13 | 
+14 14 | f"{dict(x='y')}"
+15 15 | f'{dict(x="y")}'
+16    |-f"{dict()}"
+   16 |+f"{ {} }"
+17 17 | f"a {dict()} b"
+18 18 | 
+19 19 | f"{dict(x='y') | dict(y='z')}"
+
+C408.py:17:6: C408 [*] Unnecessary `dict` call (rewrite as a literal)
+   |
+17 | f'{dict(x="y")}'
+18 | f"{dict()}"
+19 | f"a {dict()} b"
+   |      ^^^^^^ C408
+20 | 
+21 | f"{dict(x='y') | dict(y='z')}"
+   |
+   = help: Rewrite as a literal
+
+ℹ Suggested fix
+14 14 | f"{dict(x='y')}"
+15 15 | f'{dict(x="y")}'
+16 16 | f"{dict()}"
+17    |-f"a {dict()} b"
+   17 |+f"a { {} } b"
+18 18 | 
+19 19 | f"{dict(x='y') | dict(y='z')}"
+20 20 | f"{ dict(x='y') | dict(y='z') }"
+
+C408.py:19:4: C408 [*] Unnecessary `dict` call (rewrite as a literal)
+   |
+19 | f"a {dict()} b"
+20 | 
+21 | f"{dict(x='y') | dict(y='z')}"
+   |    ^^^^^^^^^^^ C408
+22 | f"{ dict(x='y') | dict(y='z') }"
+23 | f"a {dict(x='y') | dict(y='z')} b"
+   |
+   = help: Rewrite as a literal
+
+ℹ Suggested fix
+16 16 | f"{dict()}"
+17 17 | f"a {dict()} b"
+18 18 | 
+19    |-f"{dict(x='y') | dict(y='z')}"
+   19 |+f"{ {'x': 'y'} | dict(y='z')}"
+20 20 | f"{ dict(x='y') | dict(y='z') }"
+21 21 | f"a {dict(x='y') | dict(y='z')} b"
+22 22 | f"a { dict(x='y') | dict(y='z') } b"
+
+C408.py:19:18: C408 [*] Unnecessary `dict` call (rewrite as a literal)
+   |
+19 | f"a {dict()} b"
+20 | 
+21 | f"{dict(x='y') | dict(y='z')}"
+   |                  ^^^^^^^^^^^ C408
+22 | f"{ dict(x='y') | dict(y='z') }"
+23 | f"a {dict(x='y') | dict(y='z')} b"
+   |
+   = help: Rewrite as a literal
+
+ℹ Suggested fix
+16 16 | f"{dict()}"
+17 17 | f"a {dict()} b"
+18 18 | 
+19    |-f"{dict(x='y') | dict(y='z')}"
+   19 |+f"{dict(x='y') | {'y': 'z'} }"
+20 20 | f"{ dict(x='y') | dict(y='z') }"
+21 21 | f"a {dict(x='y') | dict(y='z')} b"
+22 22 | f"a { dict(x='y') | dict(y='z') } b"
+
+C408.py:20:5: C408 [*] Unnecessary `dict` call (rewrite as a literal)
+   |
+20 | f"{dict(x='y') | dict(y='z')}"
+21 | f"{ dict(x='y') | dict(y='z') }"
+   |     ^^^^^^^^^^^ C408
+22 | f"a {dict(x='y') | dict(y='z')} b"
+23 | f"a { dict(x='y') | dict(y='z') } b"
+   |
+   = help: Rewrite as a literal
+
+ℹ Suggested fix
+17 17 | f"a {dict()} b"
+18 18 | 
+19 19 | f"{dict(x='y') | dict(y='z')}"
+20    |-f"{ dict(x='y') | dict(y='z') }"
+   20 |+f"{ {'x': 'y'} | dict(y='z') }"
+21 21 | f"a {dict(x='y') | dict(y='z')} b"
+22 22 | f"a { dict(x='y') | dict(y='z') } b"
+
+C408.py:20:19: C408 [*] Unnecessary `dict` call (rewrite as a literal)
+   |
+20 | f"{dict(x='y') | dict(y='z')}"
+21 | f"{ dict(x='y') | dict(y='z') }"
+   |                   ^^^^^^^^^^^ C408
+22 | f"a {dict(x='y') | dict(y='z')} b"
+23 | f"a { dict(x='y') | dict(y='z') } b"
+   |
+   = help: Rewrite as a literal
+
+ℹ Suggested fix
+17 17 | f"a {dict()} b"
+18 18 | 
+19 19 | f"{dict(x='y') | dict(y='z')}"
+20    |-f"{ dict(x='y') | dict(y='z') }"
+   20 |+f"{ dict(x='y') | {'y': 'z'} }"
+21 21 | f"a {dict(x='y') | dict(y='z')} b"
+22 22 | f"a { dict(x='y') | dict(y='z') } b"
+
+C408.py:21:6: C408 [*] Unnecessary `dict` call (rewrite as a literal)
+   |
+21 | f"{dict(x='y') | dict(y='z')}"
+22 | f"{ dict(x='y') | dict(y='z') }"
+23 | f"a {dict(x='y') | dict(y='z')} b"
+   |      ^^^^^^^^^^^ C408
+24 | f"a { dict(x='y') | dict(y='z') } b"
+   |
+   = help: Rewrite as a literal
+
+ℹ Suggested fix
+18 18 | 
+19 19 | f"{dict(x='y') | dict(y='z')}"
+20 20 | f"{ dict(x='y') | dict(y='z') }"
+21    |-f"a {dict(x='y') | dict(y='z')} b"
+   21 |+f"a { {'x': 'y'} | dict(y='z')} b"
+22 22 | f"a { dict(x='y') | dict(y='z') } b"
+
+C408.py:21:20: C408 [*] Unnecessary `dict` call (rewrite as a literal)
+   |
+21 | f"{dict(x='y') | dict(y='z')}"
+22 | f"{ dict(x='y') | dict(y='z') }"
+23 | f"a {dict(x='y') | dict(y='z')} b"
+   |                    ^^^^^^^^^^^ C408
+24 | f"a { dict(x='y') | dict(y='z') } b"
+   |
+   = help: Rewrite as a literal
+
+ℹ Suggested fix
+18 18 | 
+19 19 | f"{dict(x='y') | dict(y='z')}"
+20 20 | f"{ dict(x='y') | dict(y='z') }"
+21    |-f"a {dict(x='y') | dict(y='z')} b"
+   21 |+f"a {dict(x='y') | {'y': 'z'} } b"
+22 22 | f"a { dict(x='y') | dict(y='z') } b"
+
+C408.py:22:7: C408 [*] Unnecessary `dict` call (rewrite as a literal)
+   |
+22 | f"{ dict(x='y') | dict(y='z') }"
+23 | f"a {dict(x='y') | dict(y='z')} b"
+24 | f"a { dict(x='y') | dict(y='z') } b"
+   |       ^^^^^^^^^^^ C408
+   |
+   = help: Rewrite as a literal
+
+ℹ Suggested fix
+19 19 | f"{dict(x='y') | dict(y='z')}"
+20 20 | f"{ dict(x='y') | dict(y='z') }"
+21 21 | f"a {dict(x='y') | dict(y='z')} b"
+22    |-f"a { dict(x='y') | dict(y='z') } b"
+   22 |+f"a { {'x': 'y'} | dict(y='z') } b"
+
+C408.py:22:21: C408 [*] Unnecessary `dict` call (rewrite as a literal)
+   |
+22 | f"{ dict(x='y') | dict(y='z') }"
+23 | f"a {dict(x='y') | dict(y='z')} b"
+24 | f"a { dict(x='y') | dict(y='z') } b"
+   |                     ^^^^^^^^^^^ C408
+   |
+   = help: Rewrite as a literal
+
+ℹ Suggested fix
+19 19 | f"{dict(x='y') | dict(y='z')}"
+20 20 | f"{ dict(x='y') | dict(y='z') }"
+21 21 | f"a {dict(x='y') | dict(y='z')} b"
+22    |-f"a { dict(x='y') | dict(y='z') } b"
+   22 |+f"a { dict(x='y') | {'y': 'z'} } b"
+
 

crates/ruff/src/rules/flake8_comprehensions/snapshots/ruff__rules__flake8_comprehensions__tests__C408_C408.py_allow_dict_calls_with_keyword_arguments.snap

@@ -55,4 +55,45 @@ C408.py:3:6: C408 [*] Unnecessary `dict` call (rewrite as a literal)
 5 5 | d3 = dict(**d2)
 6 6 | 
 
+C408.py:16:4: C408 [*] Unnecessary `dict` call (rewrite as a literal)
+   |
+16 | f"{dict(x='y')}"
+17 | f'{dict(x="y")}'
+18 | f"{dict()}"
+   |    ^^^^^^ C408
+19 | f"a {dict()} b"
+   |
+   = help: Rewrite as a literal
+
+ℹ Suggested fix
+13 13 | 
+14 14 | f"{dict(x='y')}"
+15 15 | f'{dict(x="y")}'
+16    |-f"{dict()}"
+   16 |+f"{ {} }"
+17 17 | f"a {dict()} b"
+18 18 | 
+19 19 | f"{dict(x='y') | dict(y='z')}"
+
+C408.py:17:6: C408 [*] Unnecessary `dict` call (rewrite as a literal)
+   |
+17 | f'{dict(x="y")}'
+18 | f"{dict()}"
+19 | f"a {dict()} b"
+   |      ^^^^^^ C408
+20 | 
+21 | f"{dict(x='y') | dict(y='z')}"
+   |
+   = help: Rewrite as a literal
+
+ℹ Suggested fix
+14 14 | f"{dict(x='y')}"
+15 15 | f'{dict(x="y")}'
+16 16 | f"{dict()}"
+17    |-f"a {dict()} b"
+   17 |+f"a { {} } b"
+18 18 | 
+19 19 | f"{dict(x='y') | dict(y='z')}"
+20 20 | f"{ dict(x='y') | dict(y='z') }"
+
 

crates/ruff_python_semantic/src/model.rs

@@ -783,6 +783,7 @@ impl<'a> SemanticModel<'a> {
     /// Return `true` if the context is in an f-string.
     pub const fn in_f_string(&self) -> bool {
         self.flags.contains(SemanticModelFlags::F_STRING)
+            || self.flags.contains(SemanticModelFlags::NESTED_F_STRING)
     }
 
     /// Return `true` if the context is in a nested f-string.