Function checkGrammarArrowFunction

test/fixtures/snapshot/typescript.js:88108–88121

(node, file)

                checkGrammarTypeParameterList(node.typeParameters, file);
        }
        function checkGrammarArrowFunction(node, file) {
            if (!ts.isArrowFunction(node)) {
                return false;
            }
            if (node.typeParameters && !(ts.length(node.typeParameters) > 1 || node.typeParameters.hasTrailingComma || node.typeParameters[0].constraint)) {
                if (file && ts.fileExtensionIsOneOf(file.fileName, [".mts" /* Extension.Mts */, ".cts" /* Extension.Cts */])) {
                    grammarErrorOnNode(node.typeParameters[0], ts.Diagnostics.This_syntax_is_reserved_in_files_with_the_mts_or_cts_extension_Add_a_trailing_comma_or_explicit_constraint);
                }
            }
            var equalsGreaterThanToken = node.equalsGreaterThanToken;
            var startLine = ts.getLineAndCharacterOfPosition(file, equalsGreaterThanToken.pos).line;
            var endLine = ts.getLineAndCharacterOfPosition(file, equalsGreaterThanToken.end).line;
            return startLine !== endLine && grammarErrorOnNode(equalsGreaterThanToken, ts.Diagnostics.Line_terminator_not_permitted_before_arrow);
        }
        function checkGrammarIndexSignatureParameters(node) {
            var parameter = node.parameters[0];
            if (node.parameters.length !== 1) {