Mismatching return types not detected

[wallw-teal]

Inferred union types are not producing warnings if they differ from the declared return type.

Example:

/**
 * @typedef {{name: !string, type: !string}}
 */
var SimpleColumn;

/**
 * @typedef {{name: !string, field: !string, type: !string, width: number}}
 */
var ComplexColumn;

/**
 * @return {Array<!ComplexColumn>}
 */
var getComplexColumns = function() {
  return [];
}

/**
 * @return {Array<!SimpleColumn>}
 */
var getSimpleColumns = function() {
  return [];
}

/**
 * @return {Array<!ComplexColumn>}
 */
var getColumns = function() {
  var columns;

  if (new Date().getTime() % 2 === 0) {
    columns = getComplexColumns();
  } else {
    columns = getSimpleColumns();
  }

  return columns; // should have warning for mismatching return type
}

The warning is produced properly on NTI. Is that still considered experimental or is it something that we should switch to?

Flags:

--dependency_mode STRICT --source_map_format V3 --create_source_map dist/build.min.map --summary_detail_level 3 --language_in ECMASCRIPT_2015 --warning_level VERBOSE --jscomp_error='accessControls' --jscomp_error='ambiguousFunctionDecl' --jscomp_error='checkRegExp' --jscomp_error='checkTypes' --jscomp_error='checkVars' --jscomp_error='conformanceViolations' --jscomp_error='const' --jscomp_error='constantProperty' --jscomp_error='deprecatedAnnotations' --jscomp_error='duplicateMessage' --jscomp_error='es5Strict' --jscomp_error='externsValidation' --jscomp_error='fileoverviewTags' --jscomp_error='functionParams' --jscomp_error='globalThis' --jscomp_error='internetExplorerChecks' --jscomp_error='invalidCasts' --jscomp_error='misplacedTypeAnnotation' --jscomp_error='missingGetCssName' --jscomp_error='missingPolyfill' --jscomp_error='missingProperties' --jscomp_error='missingRequire' --jscomp_error='missingReturn' --jscomp_error='moduleLoad' --jscomp_error='msgDescriptions' --jscomp_error='nonStandardJsDocs' --jscomp_error='missingSourcesWarnings' --jscomp_error='suspiciousCode' --jscomp_error='strictModuleDepCheck' --jscomp_error='typeInvalidation' --jscomp_error='undefinedNames' --jscomp_error='undefinedVars' --jscomp_error='unknownDefines' --jscomp_error='unusedLocalVariables' --jscomp_error='useOfGoogBase' --jscomp_error='uselessCode' --jscomp_error='underscore' --jscomp_error='visibility' --jscomp_warning='deprecated' --jscomp_warning='missingOverride' --jscomp_warning='unusedPrivateMembers' --jscomp_off='es3' --jscomp_off='newCheckTypes' --jscomp_off='reportUnknownTypes' --jscomp_off='missingOverride' --compilation_level ADVANCED --generate_exports --output_wrapper (function(){%output%}).call(window); --output_manifest dist/gcc-manifest --js='src/**.js' --entry_point goog:main --js_output_file dist/build.min.js

[brad4d]

@shicks
I think I remember you saying recently that this is a known failing of OTI.
Am I remembering correctly?

[dimvar]

The warning is produced properly on NTI. Is that still considered experimental or is it something that we should switch to?

NTI is not experimental anymore. You can switch to it.