Rename Arguments to Parameters in the AST (#6253)

## Summary

This PR renames a few AST nodes for clarity:

- `Arguments` is now `Parameters`
- `Arg` is now `Parameter`
- `ArgWithDefault` is now `ParameterWithDefault`

For now, the attribute names that reference `Parameters` directly are
changed (e.g., on `StmtFunctionDef`), but the attributes on `Parameters`
itself are not (e.g., `vararg`). We may revisit that decision in the
future.

For context, the AST node formerly known as `Arguments` is used in
function definitions. Formally (outside of the Python context),
"arguments" typically refers to "the values passed to a function", while
"parameters" typically refers to "the variables used in a function
definition". E.g., if you Google "arguments vs parameters", you'll get
some explanation like:

> A parameter is a variable in a function definition. It is a
placeholder and hence does not have a concrete value. An argument is a
value passed during function invocation.

We're thus deviating from Python's nomenclature in favor of a scheme
that we find to be more precise.

crates/ruff_python_ast/tests/preorder.rs

@@ -4,13 +4,13 @@ use insta::assert_snapshot;
 
 use ruff_python_ast::node::AnyNodeRef;
 use ruff_python_ast::visitor::preorder::{
-    walk_alias, walk_arg, walk_arguments, walk_comprehension, walk_except_handler, walk_expr,
-    walk_keyword, walk_match_case, walk_module, walk_pattern, walk_stmt, walk_type_param,
+    walk_alias, walk_comprehension, walk_except_handler, walk_expr, walk_keyword, walk_match_case,
+    walk_module, walk_parameter, walk_parameters, walk_pattern, walk_stmt, walk_type_param,
     walk_with_item, PreorderVisitor,
 };
 use ruff_python_ast::{
-    Alias, Arg, Arguments, BoolOp, CmpOp, Comprehension, Constant, ExceptHandler, Expr, Keyword,
-    MatchCase, Mod, Operator, Pattern, Stmt, TypeParam, UnaryOp, WithItem,
+    Alias, BoolOp, CmpOp, Comprehension, Constant, ExceptHandler, Expr, Keyword, MatchCase, Mod,
+    Operator, Parameter, Parameters, Pattern, Stmt, TypeParam, UnaryOp, WithItem,
 };
 use ruff_python_parser::lexer::lex;
 use ruff_python_parser::{parse_tokens, Mode};
@@ -231,15 +231,15 @@ impl PreorderVisitor<'_> for RecordVisitor {
         self.exit_node();
     }
 
-    fn visit_arguments(&mut self, arguments: &Arguments) {
-        self.enter_node(arguments);
-        walk_arguments(self, arguments);
+    fn visit_parameters(&mut self, parameters: &Parameters) {
+        self.enter_node(parameters);
+        walk_parameters(self, parameters);
         self.exit_node();
     }
 
-    fn visit_arg(&mut self, arg: &Arg) {
-        self.enter_node(arg);
-        walk_arg(self, arg);
+    fn visit_parameter(&mut self, parameter: &Parameter) {
+        self.enter_node(parameter);
+        walk_parameter(self, parameter);
         self.exit_node();
     }
 

crates/ruff_python_ast/tests/snapshots/preorder__decorators.snap

@@ -5,7 +5,7 @@ expression: trace
 - ModModule
   - StmtFunctionDef
     - ExprName
-    - Arguments
+    - Parameters
     - StmtPass
   - StmtClassDef
     - ExprName

crates/ruff_python_ast/tests/snapshots/preorder__function_arguments.snap

@@ -4,20 +4,20 @@ expression: trace
 ---
 - ModModule
   - StmtFunctionDef
-    - Arguments
-      - Arg
-      - Arg
-      - Arg
-      - Arg
+    - Parameters
+      - Parameter
+      - Parameter
+      - Parameter
+      - Parameter
       - ExprConstant
         - Int(20)
-      - Arg
-      - Arg
+      - Parameter
+      - Parameter
       - ExprConstant
         - Int(5)
-      - Arg
+      - Parameter
       - ExprConstant
         - Int(20)
-      - Arg
+      - Parameter
     - StmtPass
 

crates/ruff_python_ast/tests/snapshots/preorder__function_positional_only_with_default.snap

@@ -4,14 +4,14 @@ expression: trace
 ---
 - ModModule
   - StmtFunctionDef
-    - Arguments
-      - Arg
-      - Arg
+    - Parameters
+      - Parameter
+      - Parameter
       - ExprConstant
         - Int(34)
-      - Arg
+      - Parameter
       - ExprConstant
         - Int(20)
-      - Arg
+      - Parameter
     - StmtPass
 

crates/ruff_python_ast/tests/snapshots/preorder__function_type_parameters.snap

@@ -9,7 +9,7 @@ expression: trace
     - TypeParamTypeVar
     - TypeParamTypeVarTuple
     - TypeParamParamSpec
-    - Arguments
+    - Parameters
     - StmtExpr
       - ExprConstant
         - Ellipsis

crates/ruff_python_ast/tests/snapshots/visitor__decorators.snap

@@ -4,7 +4,7 @@ expression: trace
 ---
 - StmtFunctionDef
   - ExprName
-  - Arguments
+  - Parameters
   - StmtPass
 - StmtClassDef
   - ExprName

crates/ruff_python_ast/tests/snapshots/visitor__function_arguments.snap

@@ -3,17 +3,17 @@ source: crates/ruff_python_ast/tests/visitor.rs
 expression: trace
 ---
 - StmtFunctionDef
-  - Arguments
+  - Parameters
     - ExprConstant
     - ExprConstant
     - ExprConstant
-    - Arg
-    - Arg
-    - Arg
-    - Arg
-    - Arg
-    - Arg
-    - Arg
-    - Arg
+    - Parameter
+    - Parameter
+    - Parameter
+    - Parameter
+    - Parameter
+    - Parameter
+    - Parameter
+    - Parameter
   - StmtPass
 

crates/ruff_python_ast/tests/snapshots/visitor__function_positional_only_with_default.snap

@@ -3,12 +3,12 @@ source: crates/ruff_python_ast/tests/visitor.rs
 expression: trace
 ---
 - StmtFunctionDef
-  - Arguments
+  - Parameters
     - ExprConstant
     - ExprConstant
-    - Arg
-    - Arg
-    - Arg
-    - Arg
+    - Parameter
+    - Parameter
+    - Parameter
+    - Parameter
   - StmtPass
 

crates/ruff_python_ast/tests/snapshots/visitor__function_type_parameters.snap

@@ -8,7 +8,7 @@ expression: trace
   - TypeParamTypeVar
   - TypeParamTypeVarTuple
   - TypeParamParamSpec
-  - Arguments
+  - Parameters
   - StmtExpr
     - ExprConstant
 

crates/ruff_python_ast/tests/visitor.rs

@@ -7,13 +7,13 @@ use ruff_python_parser::{parse_tokens, Mode};
 
 use ruff_python_ast::node::AnyNodeRef;
 use ruff_python_ast::visitor::{
-    walk_alias, walk_arg, walk_arguments, walk_comprehension, walk_except_handler, walk_expr,
-    walk_keyword, walk_match_case, walk_pattern, walk_stmt, walk_type_param, walk_with_item,
+    walk_alias, walk_comprehension, walk_except_handler, walk_expr, walk_keyword, walk_match_case,
+    walk_parameter, walk_parameters, walk_pattern, walk_stmt, walk_type_param, walk_with_item,
     Visitor,
 };
 use ruff_python_ast::{
-    Alias, Arg, Arguments, BoolOp, CmpOp, Comprehension, ExceptHandler, Expr, Keyword, MatchCase,
-    Operator, Pattern, Stmt, TypeParam, UnaryOp, WithItem,
+    Alias, BoolOp, CmpOp, Comprehension, ExceptHandler, Expr, Keyword, MatchCase, Operator,
+    Parameter, Parameters, Pattern, Stmt, TypeParam, UnaryOp, WithItem,
 };
 
 #[test]
@@ -234,15 +234,15 @@ impl Visitor<'_> for RecordVisitor {
         self.exit_node();
     }
 
-    fn visit_arguments(&mut self, arguments: &Arguments) {
-        self.enter_node(arguments);
-        walk_arguments(self, arguments);
+    fn visit_parameters(&mut self, parameters: &Parameters) {
+        self.enter_node(parameters);
+        walk_parameters(self, parameters);
         self.exit_node();
     }
 
-    fn visit_arg(&mut self, arg: &Arg) {
-        self.enter_node(arg);
-        walk_arg(self, arg);
+    fn visit_parameter(&mut self, parameter: &Parameter) {
+        self.enter_node(parameter);
+        walk_parameter(self, parameter);
         self.exit_node();
     }