Fix double-$ prefix in assignment dependency tracking

Author: AJenbo

docs/todo/bugs.md

@@ -22,20 +22,3 @@ handle this automatically.
 `tests/psalm_assertions/method_call.php` (out of scope until
 upstream stubs land).
 
-
-## B17. Double-`$` prefix in assignment dependency tracking
-
-`src/completion/variable/forward_walk.rs` L5972-5977
-(`collect_expr_assignment_deps`) and L5985-5987
-(`collect_rhs_variables`) use `format!("${}", dv.name)` to
-construct variable names. Since `dv.name` already includes the
-`$` prefix (e.g. `"$fn"`), this produces `"$$fn"`. The bug is
-latent because both the LHS key and the RHS set values are
-consistently double-prefixed, so dependency tracking still
-works. However, any code that compares these names against
-normally-prefixed variable names (single `$`) would fail to
-match.
-
-**Fix:** Remove the `format!("${}", ...)` wrapper and use
-`dv.name.to_string()` directly in both functions.
-

src/completion/variable/forward_walk.rs

@@ -5970,7 +5970,7 @@ fn collect_expr_assignment_deps(
     if let Expression::Assignment(assign) = expr
         && let Expression::Variable(Variable::Direct(dv)) = assign.lhs
     {
-        let lhs_name = format!("${}", dv.name);
+        let lhs_name = dv.name.to_string();
         let mut rhs_vars = HashSet::new();
         collect_rhs_variables(assign.rhs, &mut rhs_vars);
         deps.entry(lhs_name).or_default().extend(rhs_vars);
@@ -5983,7 +5983,7 @@ fn collect_rhs_variables(expr: &Expression<'_>, vars: &mut HashSet<String>) {
 
     match expr {
         Expression::Variable(Variable::Direct(dv)) => {
-            vars.insert(format!("${}", dv.name));
+            vars.insert(dv.name.to_string());
         }
         Expression::Binary(binary) => {
             collect_rhs_variables(binary.lhs, vars);