Parser errors prevent CodeProvider execution (completion, goto definition etc)

[simerplaha]

Code completion relies on the parsed AST. When the parser fails, the AST (parser) becomes unavailable for code completion.

For example: The following test fails because contract is not a valid keyword, which gets rejected by the ralphc parser, making the AST (parser) unavailable for code completion at line 1.

val suggestions =
  TestCodeCompleter(
    """
      |import "std/@@"
      |
      |contract Test() { }
      |""".stripMargin)

suggestions should not be empty

This will be case for all code completion providers and every other implementation that needs the AST like go-to definitions, quick-fix suggestions etc.

[simerplaha]

Hey @tdroxler, just wanted to draw your attention to this issue. It's can be a bit annoying that a single parser error disables LSP features such as go-to definition and auto-completion due to the unavailability of the AST (see above example scenario). Ralph's parser is a bit too strict for us at the moment. It would be nice if most errors could be deferred to the compilation phase.

For example:

• Instead of immediately flagging priv fn as an error in the parser, priv could be stored as Ast.FuncModifier and validated during compilation.
• Errors like checking duplicate enum fields, empty fields, etc., don't necessarily need to be parser errors, they could be handled as compilation errors.
• The syntax MyEnum. or myEnum. is also immediately rejected by the parser, thus preventing autocomplete after the dot.
• There are a few other cases like these.

If the parser could parse the syntax with a bit more flexibility, developers might intentionally write incorrect code, relying on auto-complete to catch these mistakes.