plankevm

Mandatory use when adding, modifying, or reviewing diagnostic emission in any frontend pipeline stage. Use when touching emit_ methods, Session::emit_diagnostic, or the Diagnostic/Cause/Claim builder API.

Mandatory use when editing or defining data structures in the compiler.

Mandatory use when developing or analyzing the parser, CST, lexer, or AST. Use when adding new syntax constructs, fixing parse errors, improving error recovery, or debugging tokenization issues.