Fix userAssert's type annotation (#28191)

* Fix userAssert's type annotation

Matches `devAssert`'s change in #24047.

* Remove old notes

* Add single cast

Closure is narrowing the type to `Object` due to the `typeof x === 'object'` check. Seems like a bug.

* Speed up check-types by 30s

build-system/compile/compile.js

@@ -315,6 +315,8 @@ function compile(
     // See https://github.com/google/closure-compiler/wiki/Warnings#warnings-categories
     // for a full list of closure's default error / warning levels.
     if (options.typeCheckOnly) {
+      compilerOptions.checks_only = true;
+
       // Don't modify compilation_level to a lower level since
       // it won't do strict type checking if its whitespace only.
       compilerOptions.define.push('TYPECHECK_ONLY=true');

extensions/amp-analytics/0.1/events.js

@@ -1112,7 +1112,7 @@ export class TimerEventTracker extends EventTracker {
     }
 
     const timerHandler = new TimerEventHandler(
-      timerSpec,
+      /** @type {!JsonObject} */ (timerSpec),
       startBuilder,
       stopBuilder
     );

src/log.js

@@ -385,9 +385,6 @@ export class Log {
    *   elements in an array. When e.g. passed to console.error this yields
    *   native displays of things like HTML elements.
    *
-   * NOTE: for an explanation of the tempate R implementation see
-   * https://github.com/google/closure-library/blob/08858804/closure/goog/asserts/asserts.js#L192-L213
-   *
    * @param {T} shouldBeTrueish The value to assert. The assert fails if it does
    *     not evaluate to true.
    * @param {!Array|string=} opt_message The assertion message
@@ -877,9 +874,6 @@ export function isFromEmbed(win, opt_element) {
  *   elements in an array. When e.g. passed to console.error this yields
  *   native displays of things like HTML elements.
  *
- * NOTE: for an explanation of the tempate R implementation see
- * https://github.com/google/closure-library/blob/08858804/closure/goog/asserts/asserts.js#L192-L213
- *
  * @param {T} shouldBeTrueish The value to assert. The assert fails if it does
  *     not evaluate to true.
  * @param {!Array|string=} opt_message The assertion message
@@ -940,9 +934,6 @@ export function devAssert(
  *   elements in an array. When e.g. passed to console.error this yields
  *   native displays of things like HTML elements.
  *
- * NOTE: for an explanation of the tempate R implementation see
- * https://github.com/google/closure-library/blob/08858804/closure/goog/asserts/asserts.js#L192-L213
- *
  * @param {T} shouldBeTrueish The value to assert. The assert fails if it does
  *     not evaluate to true.
  * @param {!Array|string=} opt_message The assertion message
@@ -955,18 +946,10 @@ export function devAssert(
  * @param {*=} opt_7 Optional argument
  * @param {*=} opt_8 Optional argument
  * @param {*=} opt_9 Optional argument
- * @return {R} The value of shouldBeTrueish.
+ * @return {T} The value of shouldBeTrueish.
+ * @throws {!Error} When `shouldBeTrueish` is falsey.
  * @template T
- * @template R :=
- *     mapunion(T, (V) =>
- *         cond(eq(V, 'null'),
- *             none(),
- *             cond(eq(V, 'undefined'),
- *                 none(),
- *                 V)))
- *  =:
- * @throws {!Error} When `value` is `null` or `undefined`.
- * @closurePrimitive {asserts.matchesReturn}
+ * @closurePrimitive {asserts.truthy}
  */
 export function userAssert(
   shouldBeTrueish,