TypeErrors.ts — react Source File

Source Code

import {CompilerError, SourceLocation} from '..';
import {
  ConcreteType,
  printConcrete,
  printType,
  StructuralValue,
  Type,
  VariableId,
} from './Types';

export function unsupportedLanguageFeature(
  desc: string,
  loc: SourceLocation,
): never {
  CompilerError.throwInvalidJS({
    reason: `Typedchecker does not currently support language feature: ${desc}`,
    loc,
  });
}

export type UnificationError =
  | {
      kind: 'TypeUnification';
      left: ConcreteType<Type>;
      right: ConcreteType<Type>;
    }
  | {
      kind: 'StructuralUnification';
      left: StructuralValue;
      right: ConcreteType<Type>;
    };

function printUnificationError(err: UnificationError): string {
  if (err.kind === 'TypeUnification') {
    return `${printConcrete(err.left, printType)} is incompatible with ${printConcrete(err.right, printType)}`;
  } else {
    return `structural ${err.left.kind} is incompatible with ${printConcrete(err.right, printType)}`;
  }
}

export function raiseUnificationErrors(
  errs: null | Array<UnificationError>,
  loc: SourceLocation,
): void {
  if (errs != null) {
    if (errs.length === 0) {
      CompilerError.invariant(false, {
        reason: 'Should not have array of zero errors',
        loc,
      });
    } else if (errs.length === 1) {
      CompilerError.throwInvalidJS({
        reason: `Unable to unify types because ${printUnificationError(errs[0])}`,
        loc,
      });
    } else {
      const messages = errs
        .map(err => `\t* ${printUnificationError(err)}`)
        .join('\n');
      CompilerError.throwInvalidJS({
// ... (72 more lines)