fix: ensure the ecma version is correct when calling parser using flat config

Author: G-Rath

tests/src/core/parse.js

@@ -136,6 +136,6 @@ describe('parse(content, { settings, ecmaFeatures })', function () {
   it('prefers languageOptions.parserOptions over parserOptions', () => {
     const parseSpy = sinon.spy();
     parseStubParser.parse = parseSpy;
-    expect(parse.bind(null, path, content, { settings: {}, parserPath: 'espree', languageOptions: { parserOptions: { sourceType: 'module', ecmaVersion: 2015, ecmaFeatures: { jsx: true } } }, parserOptions: { sourceType: 'script' } })).not.to.throw(Error);
+    expect(parse.bind(null, path, content, { settings: {}, parserPath: 'espree', languageOptions: { sourceType: 'module', ecmaVersion: 2015, parserOptions: { sourceType: 'module', ecmaFeatures: { jsx: true } } }, parserOptions: { sourceType: 'script' } })).not.to.throw(Error);
   });
 });

utils/parse.js

@@ -116,6 +116,11 @@ exports.default = function parse(path, content, context) {
   parserOptions = Object.assign({}, parserOptions);
   parserOptions.ecmaFeatures = Object.assign({}, parserOptions.ecmaFeatures);
 
+  // fallback to the ecma version in languageOptions when using flat config
+  if (context.languageOptions) {
+    parserOptions.ecmaVersion = parserOptions.ecmaVersion || context.languageOptions.ecmaVersion;
+  }
+
   // always include comments and tokens (for doc parsing)
   parserOptions.comment = true;
   parserOptions.attachComment = true;  // keeping this for backward-compat with  older parsers