Disallow var

[cs01]

Summary

• Disallow the var keyword in ChadScript source files
• Emit a compile-time error with file/line/column on var usage
• let and const are the only allowed variable declaration keywords

Details

var is semantically confusing (function-scoped, hoisted) and provides no value over let/const. This change rejects it at parse time rather than silently compiling it.

Error format:

src/main.ts:5:3: error: 'var' is not allowed; use 'let' or 'const'

Files changed

• src/parser-ts/transformer.ts — catches var in top-level variable statements
• src/parser-ts/handlers/statements.ts — catches var in function bodies and for/for-of/for-in initializers
• src/parser-native/transformer.ts — catches var in both the tree-sitter variable_declaration node and for-loop keyword scanning

Test plan

• var x = 5 at top level → compiler error, exit 1
• var x = 5 inside a function → compiler error, exit 1
• for (var i = 0; ...) → compiler error, exit 1
• for (var x of arr) → compiler error, exit 1
• let and const continue to work normally
• All 276 existing tests pass