Completion for superclasses

[jez]

Input

→ View on sorbet.run

# typed: true
class Parent; end
class Child < Pare
  #               ^ completion: Parent

Observed output

s(:begin,
  s(:class,
    s(:const, nil, :Parent), nil, nil),
  s(:class,
    s(:const, nil, :Child),
    s(:const, nil, :Pare), nil))
editor.rb:4: unexpected token "end of file" https://srb.help/2001
     4 |  #               ^ completion: Parent
     5 |

editor.rb:3: Hint: this "class" token is not closed before the end of the file https://srb.help/2003
     3 |class Child < Pare
        ^^^^^

editor.rb:3: Unable to resolve constant Pare https://srb.help/5002
     3 |class Child < Pare
                      ^^^^
  Did you mean Rake? Use -a to autocorrect
    editor.rb:3: Replace with Rake
     3 |class Child < Pare
                      ^^^^
    https://github.com/sorbet/sorbet/tree/master/rbi/gems/rake.rbi#L6: Rake defined here
     6 |module Rake
        ^^^^^^^^^^^
  Did you mean Date? Use -a to autocorrect
    editor.rb:3: Replace with Date
     3 |class Child < Pare
                      ^^^^
    https://github.com/sorbet/sorbet/tree/master/rbi/stdlib/date.rbi#L159: Date defined here
     159 |class Date
          ^^^^^^^^^^
  Did you mean Parent? Use -a to autocorrect
    editor.rb:3: Replace with Parent
     3 |class Child < Pare
                      ^^^^
    editor.rb:2: Parent defined here
     2 |class Parent; end
        ^^^^^^^^^^^^

editor.rb:3: Unable to resolve constant Pare https://srb.help/5002
     3 |class Child < Pare
                      ^^^^
  Did you mean Rake? Use -a to autocorrect
    editor.rb:3: Replace with Rake
     3 |class Child < Pare
                      ^^^^
    https://github.com/sorbet/sorbet/tree/master/rbi/gems/rake.rbi#L6: Rake defined here
     6 |module Rake
        ^^^^^^^^^^^
  Did you mean Date? Use -a to autocorrect
    editor.rb:3: Replace with Date
     3 |class Child < Pare
                      ^^^^
    https://github.com/sorbet/sorbet/tree/master/rbi/stdlib/date.rbi#L159: Date defined here
     159 |class Date
          ^^^^^^^^^^
  Did you mean Parent? Use -a to autocorrect
    editor.rb:3: Replace with Parent
     3 |class Child < Pare
                      ^^^^
    editor.rb:2: Parent defined here
     2 |class Parent; end
        ^^^^^^^^^^^^
Errors: 4

Expected behavior

It would be nice to show completion results for constant literals in superclass positions.
It's quite possible that this would not be immediately useful, because every keystroke would trigger a slow path edit, which would be prohibitively expensive on large codebases, but it would be passable on small codebases and would be a step in the right direction for large codebases.

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Note that we already recover from the typical parse error that users would see here, so there's likely no parser changes holding us back from making practical improvements here.