fix: better handling of SelfParam in inline_call

Author: roife

crates/ide-assists/src/handlers/inline_call.rs

@@ -15,7 +15,7 @@ use ide_db::{
 };
 use itertools::{izip, Itertools};
 use syntax::{
- ast::{self, edit::IndentLevel, edit_in_place::Indent, HasArgList, PathExpr},
+ ast::{self, edit::IndentLevel, edit_in_place::Indent, HasArgList, Pat, PathExpr},
  ted, AstNode, NodeOrToken, SyntaxKind,
 };
 
@@ -278,7 +278,7 @@ fn get_fn_params(
 
  let mut params = Vec::new();
  if let Some(self_param) = param_list.self_param() {
- // FIXME this should depend on the receiver as well as the self_param
+ // Keep `ref` and `mut` and transform them into `&` and `mut` later
  params.push((
  make::ident_pat(
  self_param.amp_token().is_some(),
@@ -409,16 +409,56 @@ fn inline(
  let mut let_stmts = Vec::new();
 
  // Inline parameter expressions or generate `let` statements depending on whether inlining works or not.
- for ((pat, param_ty, _), usages, expr) in izip!(params, param_use_nodes, arguments) {
+ for ((pat, param_ty, param), usages, expr) in izip!(params, param_use_nodes, arguments) {
  // izip confuses RA due to our lack of hygiene info currently losing us type info causing incorrect errors
  let usages: &[ast::PathExpr] = &usages;
  let expr: &ast::Expr = expr;
 
  let mut insert_let_stmt = || {
  let ty = sema.type_of_expr(expr).filter(TypeInfo::has_adjustment).and(param_ty.clone());
- let_stmts.push(
- make::let_stmt(pat.clone(), ty, Some(expr.clone())).clone_for_update().into(),
- );
+
+ let is_self = param
+ .name(sema.db)
+ .and_then(|name| name.as_text())
+ .is_some_and(|name| name == "self");
+
+ if is_self {
+ let mut this_pat = make::ident_pat(false, false, make::name("this"));
+ let mut expr = expr.clone();
+ match pat {
+ Pat::IdentPat(pat) => match (pat.ref_token(), pat.mut_token()) {
+ // self => let this = obj
+ (None, None) => {}
+ // mut self => let mut this = obj
+ (None, Some(_)) => {
+ this_pat = make::ident_pat(false, true, make::name("this"));
+ }
+ // &self => let this = &obj
+ (Some(_), None) => {
+ expr = make::expr_ref(expr, false);
+ }
+ // let foo = &mut X; &mut self => let this = &mut obj
+ // let mut foo = X; &mut self => let this = &mut *obj (reborrow)
+ (Some(_), Some(_)) => {
+ let should_reborrow = sema
+ .type_of_expr(&expr)
+ .map(|ty| ty.original.is_mutable_reference());
+ expr = if let Some(true) = should_reborrow {
+ make::expr_reborrow(expr)
+ } else {
+ make::expr_ref(expr, true)
+ };
+ }
+ },
+ _ => {}
+ };
+ let_stmts
+ .push(make::let_stmt(this_pat.into(), ty, Some(expr)).clone_for_update().into())
+ } else {
+ let_stmts.push(
+ make::let_stmt(pat.clone(), ty, Some(expr.clone())).clone_for_update().into(),
+ );
+ }
  };
 
  // check if there is a local var in the function that conflicts with parameter

crates/syntax/src/ast/make.rs

@@ -595,6 +595,9 @@ pub fn expr_macro_call(f: ast::Expr, arg_list: ast::ArgList) -> ast::Expr {
 pub fn expr_ref(expr: ast::Expr, exclusive: bool) -> ast::Expr {
  expr_from_text(&if exclusive { format!("&mut {expr}") } else { format!("&{expr}") })
 }
+pub fn expr_reborrow(expr: ast::Expr) -> ast::Expr {
+ expr_from_text(&format!("&mut *{expr}"))
+}
 pub fn expr_closure(pats: impl IntoIterator<Item = ast::Param>, expr: ast::Expr) -> ast::Expr {
  let params = pats.into_iter().join(", ");
  expr_from_text(&format!("|{params}| {expr}"))