Function reScanTemplateToken

test/fixtures/snapshot/typescript.js:11995–11999

* Unconditionally back up and scan a template expression portion.

(isTaggedTemplate)

         * Unconditionally back up and scan a template expression portion.
         */
        function reScanTemplateToken(isTaggedTemplate) {
            ts.Debug.assert(token === 19 /* SyntaxKind.CloseBraceToken */, "'reScanTemplateToken' should only be called on a '}'");
            pos = tokenPos;
            return token = scanTemplateAndSetTokenValue(isTaggedTemplate);
        }
        function reScanTemplateHeadOrNoSubstitutionTemplate() {
            pos = tokenPos;
            return token = scanTemplateAndSetTokenValue(/* isTaggedTemplate */ true);