Implement the same safe_ident strategy that codegen uses for parameter names that might collide with keywords

Document duplicated definition of `safe_ident`

Add test for `safe_ident` parameter identifier generation for `#[godot-api]` virtual call generation

Author: ambeeeeee

godot-codegen/src/special_cases/codegen_special_cases.rs

@@ -137,6 +137,7 @@ const SELECTED_CLASSES: &[&str] = &[
     "CollisionShape2D",
     "Control",
     "EditorPlugin",
+    "EditorExportPlugin",
     "Engine",
     "FileAccess",
     "GDScript",

godot-codegen/src/util.rs

@@ -83,6 +83,7 @@ pub fn cstr_u8_slice(string: &str) -> Literal {
     Literal::byte_string(format!("{string}\0").as_bytes())
 }
 
+// This function is duplicated in godot-macros\src\util\mod.rs
 #[rustfmt::skip]
 pub fn safe_ident(s: &str) -> Ident {
     // See also: https://doc.rust-lang.org/reference/keywords.html

godot-macros/src/class/data_models/func.rs

@@ -5,7 +5,7 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/.
  */
 
-use crate::util::{bail_fn, ident};
+use crate::util::{bail_fn, ident, safe_ident};
 use crate::{util, ParseResult};
 use proc_macro2::{Group, Ident, TokenStream, TokenTree};
 use quote::{format_ident, quote};
@@ -368,7 +368,7 @@ pub(crate) fn maybe_rename_parameter(param_ident: Ident, next_unnamed_index: &mu
         // This could technically collide with another parameter of the same name (without "_"), but that's very unlikely and not
         // something we really need to support.
         // Note that the case of a single "_" is handled above.
-        ident(remain)
+        safe_ident(remain)
     } else {
         param_ident
     }

godot-macros/src/util/mod.rs

@@ -273,3 +273,27 @@ pub fn make_virtual_tool_check() -> TokenStream {
 pub fn make_virtual_tool_check() -> TokenStream {
     TokenStream::new()
 }
+
+// This function is duplicated in godot-codegen\src\util.rs
+#[rustfmt::skip]
+pub fn safe_ident(s: &str) -> Ident {
+    // See also: https://doc.rust-lang.org/reference/keywords.html
+    match s {
+        // Lexer
+        | "as" | "break" | "const" | "continue" | "crate" | "else" | "enum" | "extern" | "false" | "fn" | "for" | "if"
+        | "impl" | "in" | "let" | "loop" | "match" | "mod" | "move" | "mut" | "pub" | "ref" | "return" | "self" | "Self"
+        | "static" | "struct" | "super" | "trait" | "true" | "type" | "unsafe" | "use" | "where" | "while"
+
+        // Lexer 2018+
+        | "async" | "await" | "dyn"
+
+        // Reserved
+        | "abstract" | "become" | "box" | "do" | "final" | "macro" | "override" | "priv" | "typeof" | "unsized" | "virtual" | "yield"
+
+        // Reserved 2018+
+        | "try"
+           => format_ident!("{}_", s),
+
+         _ => ident(s)
+    }
+}

itest/rust/src/register_tests/keyword_parameters_test.rs

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) godot-rust; Bromeon and contributors.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+// Needed for Clippy to accept #[cfg(all())]
+#![allow(clippy::non_minimal_cfg)]
+
+use godot::classes::{EditorExportPlugin, IEditorExportPlugin};
+use godot::prelude::*;
+
+#[derive(GodotClass)]
+#[class(base=EditorExportPlugin, init)]
+struct KeywordParameterEditorExportPlugin {
+    _base: Base<EditorExportPlugin>,
+}
+
+#[godot_api]
+impl IEditorExportPlugin for KeywordParameterEditorExportPlugin {
+    // This test requires that the second non-self parameter on `export_file`
+    // remain named `_type`. Additionally tell rustfmt to skip this code and
+    // allow all clippy lints.
+    #[allow(clippy::all)]
+    #[rustfmt::skip]
+    fn export_file(&mut self, _path: GString, _type: GString, _features: PackedStringArray) { }
+}

itest/rust/src/register_tests/mod.rs

@@ -10,6 +10,7 @@ mod conversion_test;
 mod derive_variant_test;
 mod func_test;
 mod gdscript_ffi_test;
+mod keyword_parameters_test;
 mod option_ffi_test;
 mod var_test;