[FIX] compiler: never add _ prefix to non variable token

src/compiler/inline_expressions.ts

@@ -329,7 +329,7 @@ export function compileExprToArray(expr: string): Token[] {
   // Mark all variables that have been used locally.
   // This assumes the expression has only one scope (incorrect but "good enough for now")
   for (const token of tokens) {
-    if (token.type === "SYMBOL" && localVars.has(token.value)) {
+    if (token.type === "SYMBOL" && token.varName && localVars.has(token.value)) {
       token.originalValue = token.value;
       token.value = `_${token.value}`;
       token.isLocal = true;