[ty] Add quick fix to remove redundant cast

crates/ruff_python_ast/src/nodes.rs

@@ -116,7 +116,7 @@ impl ExprRef<'_> {
     }
 
     pub fn precedence(&self) -> OperatorPrecedence {
-        OperatorPrecedence::from(self)
+        OperatorPrecedence::from(*self)
     }
 }
 

crates/ruff_python_ast/src/operator_precedence.rs

@@ -54,7 +54,7 @@ pub enum OperatorPrecedence {
 }
 
 impl OperatorPrecedence {
-    pub fn from_expr_ref(expr: &ExprRef) -> Self {
+    pub fn from_expr_ref(expr: ExprRef) -> Self {
         match expr {
             // Binding or parenthesized expression, list display, dictionary display, set display
             ExprRef::Tuple(_)
@@ -130,7 +130,7 @@ impl OperatorPrecedence {
     }
 
     pub fn from_expr(expr: &Expr) -> Self {
-        Self::from(&ExprRef::from(expr))
+        Self::from(ExprRef::from(expr))
     }
 
     /// Returns `true` if the precedence is right-associative i.e., the operations are evaluated
@@ -146,8 +146,8 @@ impl From<&Expr> for OperatorPrecedence {
     }
 }
 
-impl<'a> From<&ExprRef<'a>> for OperatorPrecedence {
-    fn from(expr_ref: &ExprRef<'a>) -> Self {
+impl<'a> From<ExprRef<'a>> for OperatorPrecedence {
+    fn from(expr_ref: ExprRef<'a>) -> Self {
         Self::from_expr_ref(expr_ref)
     }
 }

crates/ty_python_semantic/resources/mdtest/directives/cast.md

@@ -114,6 +114,15 @@ warning[redundant-cast]: Value is already of type `int`
 5 | cast(int, secrets.randbelow(10))
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
+help: Remove the redundant `cast`
+2 | from typing import cast
+3 |
+4 | # snapshot: redundant-cast
+  - cast(int, secrets.randbelow(10))
+5 + secrets.randbelow(10)
+6 | # snapshot: redundant-cast
+7 | cast(val=secrets.randbelow(10), typ=int)
+8 | def f(x: int, y: int, z: int) -> int:
 ```
 
 ```py
@@ -128,4 +137,82 @@ warning[redundant-cast]: Value is already of type `int`
 7 | cast(val=secrets.randbelow(10), typ=int)
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
+help: Remove the redundant `cast`
+4  | # snapshot: redundant-cast
+5  | cast(int, secrets.randbelow(10))
+6  | # snapshot: redundant-cast
+   - cast(val=secrets.randbelow(10), typ=int)
+7  + secrets.randbelow(10)
+8  | def f(x: int, y: int, z: int) -> int:
+9  |     # snapshot: redundant-cast
+10 |     return cast(int, x + y) * z
+```
+
+```py
+def f(x: int, y: int, z: int) -> int:
+    # snapshot: redundant-cast
+    return cast(int, x + y) * z
+```
+
+```snapshot
+warning[redundant-cast]: Value is already of type `int`
+  --> src/mdtest_snippet.py:10:12
+   |
+10 |     return cast(int, x + y) * z
+   |            ^^^^^^^^^^^^^^^^
+   |
+help: Remove the redundant `cast`
+7  | cast(val=secrets.randbelow(10), typ=int)
+8  | def f(x: int, y: int, z: int) -> int:
+9  |     # snapshot: redundant-cast
+   -     return cast(int, x + y) * z
+10 +     return (x + y) * z
+11 | def g(x: int, y: int) -> int:
+12 |     # snapshot: redundant-cast
+13 |     return -cast(int, x + y)
+```
+
+```py
+def g(x: int, y: int) -> int:
+    # snapshot: redundant-cast
+    return -cast(int, x + y)
+```
+
+```snapshot
+warning[redundant-cast]: Value is already of type `int`
+  --> src/mdtest_snippet.py:13:13
+   |
+13 |     return -cast(int, x + y)
+   |             ^^^^^^^^^^^^^^^^
+   |
+help: Remove the redundant `cast`
+10 |     return cast(int, x + y) * z
+11 | def g(x: int, y: int) -> int:
+12 |     # snapshot: redundant-cast
+   -     return -cast(int, x + y)
+13 +     return -(x + y)
+14 | def h(x: int, y: int) -> None:
+15 |     # snapshot: redundant-cast
+16 |     print(cast(int, x + y))
+```
+
+```py
+def h(x: int, y: int) -> None:
+    # snapshot: redundant-cast
+    print(cast(int, x + y))
+```
+
+```snapshot
+warning[redundant-cast]: Value is already of type `int`
+  --> src/mdtest_snippet.py:16:11
+   |
+16 |     print(cast(int, x + y))
+   |           ^^^^^^^^^^^^^^^^
+   |
+help: Remove the redundant `cast`
+13 |     return -cast(int, x + y)
+14 | def h(x: int, y: int) -> None:
+15 |     # snapshot: redundant-cast
+   -     print(cast(int, x + y))
+16 +     print(x + y)
 ```

crates/ty_python_semantic/resources/mdtest/snapshots/typed_dict.md_-_`TypedDict`_-_Redundant_cast_warni…_(75ac240a2d1f7108).snap

@@ -1,5 +1,5 @@
 ---
-source: crates/ty_test/src/lib.rs
+source: crates/mdtest/src/lib.rs
 expression: snapshot
 ---
 
@@ -35,6 +35,13 @@ warning[redundant-cast]: Value is already of type `Foo2`
 10 | _ = cast(Foo2, foo)  # error: [redundant-cast]
    |     ^^^^^^^^^^^^^^^
    |
+help: Remove the redundant `cast`
+7  |     x: int
+8  |
+9  | foo: Foo2 = {"x": 1}
+   - _ = cast(Foo2, foo)  # error: [redundant-cast]
+10 + _ = foo  # error: [redundant-cast]
+11 | _ = cast(Bar2, foo)  # error: [redundant-cast]
 
 ```
 
@@ -46,5 +53,11 @@ warning[redundant-cast]: Value is already of type `Bar2`
    |     ^^^^^^^^^^^^^^^
    |
 info: `Bar2` is equivalent to `Foo2`
+help: Remove the redundant `cast`
+8  |
+9  | foo: Foo2 = {"x": 1}
+10 | _ = cast(Foo2, foo)  # error: [redundant-cast]
+   - _ = cast(Bar2, foo)  # error: [redundant-cast]
+11 + _ = foo  # error: [redundant-cast]
 
 ```

crates/ty_python_semantic/src/types/function.rs

@@ -55,7 +55,10 @@ use bitflags::bitflags;
 use ruff_db::diagnostic::{Annotation, DiagnosticId, Severity, Span};
 use ruff_db::files::{File, FileRange};
 use ruff_db::parsed::{ParsedModuleRef, parsed_module};
-use ruff_python_ast::{self as ast, ParameterWithDefault};
+use ruff_db::source::source_text;
+use ruff_diagnostics::{Edit, Fix};
+use ruff_python_ast::find_node::covering_node;
+use ruff_python_ast::{self as ast, OperatorPrecedence, ParameterWithDefault};
 use ruff_text_size::Ranged;
 use salsa::plumbing::AsId;
 use ty_module_resolver::{KnownModule, ModuleName, file_to_module, resolve_module};
@@ -2232,6 +2235,31 @@ impl KnownFunction {
                                 "`{casted_display}` is equivalent to `{source_display}`",
                             ));
                         }
+                        if let Some(value) = call_expression.arguments.find_argument_value("val", 1)
+                        {
+                            let covering = covering_node(
+                                context.module().syntax().into(),
+                                call_expression.range(),
+                            );
+                            let needs_parens = covering
+                                .parent()
+                                .and_then(ast::AnyNodeRef::as_expr_ref)
+                                .is_some_and(|parent| {
+                                    let value_precedence = OperatorPrecedence::from_expr(value);
+                                    OperatorPrecedence::from_expr_ref(parent) >= value_precedence
+                                });
+                            let value_text = &source_text(db, file)[value.range()];
+                            let replacement = if needs_parens {
+                                format!("({value_text})")
+                            } else {
+                                value_text.to_string()
+                            };
+                            diagnostic.help("Remove the redundant `cast`");
+                            diagnostic.set_fix(Fix::safe_edit(Edit::range_replacement(
+                                replacement,
+                                call_expression.range(),
+                            )));
+                        }
                     }
                 }
             }