Non-platform TokenSet declared in ParserDefinition

Reports TokenSet field declarations referencing non-platform element types in ParserDefinition classes.

All languages ParserDefinition are created on the application startup. Declaring a TokenSet referencing non-platform language element types may cause creating and registering all the language element types in the holder class of the referenced type, even if a project doesn't contain any files in this language.

Example:

// element types holder:
public interface MyLangTokenTypes {
  IElementType COMMENT = new MyLangTokenType("COMMENT");
  IElementType TYPE1 = new MyLangTokenType("TYPE1");
  IElementType TYPE2 = new MyLangTokenType("TYPE2");
  // more types...
}


// bad:

public class MyLangParserDefinition implements ParserDefinition {
  // this field causes initializing and registering all the types from MyLangTokenTypes:
  private static final TokenSet COMMENTS = TokenSet.create(MyLangTokenTypes.COMMENT);

  @NotNull
  @Override
  public TokenSet getCommentTokens() {
    return COMMENTS;
  }
  ...
}


// good:

public final class MyLangTokenSets {
  public static final TokenSet COMMENTS = TokenSet.create(MyLangTokenTypes.COMMENT);
}

public class MyLangParserDefinition implements ParserDefinition {
  @NotNull
  @Override
  public TokenSet getCommentTokens() {
    // types are referenced and registered only when this method is called:
    return MyLangTokenSets.COMMENTS;
  }
  ...
}

// good (Kotlin):

// top-level declaration is not loaded until getCommentTokens() method is called:
private val COMMENTS = TokenSet.create(MyLangTokenTypes.COMMENT);

class MyLangParserDefinition : ParserDefinition {
  override getCommentTokens(): TokenSet {
    return COMMENTS;
  }
  ...
}

// good:

public class MyLangParserDefinition implements ParserDefinition {
  // allowed platform TokenSet:
  private static final TokenSet COMMENTS1 = TokenSet.EMPTY;
  // allowed platform TokenType:
  private static final TokenSet COMMENTS2 = TokenSet.create(TokenType.WHITE_SPACE);

  @NotNull
  @Override
  public TokenSet getCommentTokens() {
    ...
  }
  ...
}

Locating this inspection

By ID

Can be used to locate inspection in e.g. Qodana configuration files, where you can quickly enable or disable it, or adjust its settings.

TokenSetInParserDefinition

Via Settings dialog

Path to the inspection settings via IntelliJ Platform IDE Settings dialog, when you need to adjust inspection settings directly from your IDE.

Settings or Preferences | Editor | Inspections | Plugin DevKit | Code

New in 2023.2

Inspection Details
By default bundled with:	IntelliJ IDEA 2024.2, Qodana for JVM 2024.2,
Can be installed with plugin:	Plugin DevKit, 242.22892

Last modified: 11 September 2024