IllegalArgumentException.class, () -> checkArgument(false, "A %s C", (Object) null));
    assertThat(e).hasMessageThat().isEqualTo("A null C");
  }

  @J2ktIncompatible // TODO(b/319404022): Allow passing null array as varargs
  public void testCheckArgument_singleNullArray_failure() {
    IllegalArgumentException e =
        assertThrows(

### Always `raise` in Dependencies with `yield` and `except`

If you catch an exception in a dependency with `yield`, unless you are raising another `HTTPException` or similar, you should re-raise the original exception.

 * reasonable and it will be fine.
 *
 * <ul>
 *   <li>If checking whether the <i>caller</i> has violated your method or constructor's contract
 *       (such as by passing an invalid argument), use the utilities of the {@link Preconditions}
 *       class instead.
 *   <li>If checking an <i>impossible</i> condition (which <i>cannot</i> happen unless your own

   *
   * @param formal The type whose type variables or itself is mapped to other type(s). It's almost
   *     always a bug if {@code formal} isn't a type variable and contains no type variable. Make
   *     sure you are passing the two parameters in the right order.
   * @param actual The type that the formal type variable(s) are mapped to. It can be or contain yet
   *     other type variables, in which case these type variables will be further resolved if

We can declare all that without having to modify the original `APIRouter` by passing those parameters to `app.include_router()`:

```Python hl_lines="14-17" title="app/main.py"
{!../../docs_src/bigger_applications/app/main.py!}
```

 * reasonable and it will be fine.
 *
 * <ul>
 *   <li>If checking whether the <i>caller</i> has violated your method or constructor's contract
 *       (such as by passing an invalid argument), use the utilities of the {@link Preconditions}
 *       class instead.
 *   <li>If checking an <i>impossible</i> condition (which <i>cannot</i> happen unless your own

same function in **other places** without FastAPI, and it would **work as expected**. If there's a **required** parameter (without a default value), your **editor** will let you know with an error, **Python** will also complain if you run it without passing the required parameter.

When you don't use `Annotated` and instead use the **(old) default value style**, if you call that function without FastAPI in **other places**, you have to **remember** to pass the arguments to the function for...

    return collection.stream();
  }

  /**
   * Returns a sequential {@link Stream} of the remaining contents of {@code iterator}. Do not use
   * {@code iterator} directly after passing it to this method.
   */
  public static <T extends @Nullable Object> Stream<T> stream(Iterator<T> iterator) {
    return StreamSupport.stream(Spliterators.spliteratorUnknownSize(iterator, 0), false);
  }

  /**

      Throwable cause = e.getCause();
      if (policy.isExpectedType(cause)) {
        return;
      }
      throw new AssertionError(
          String.format(
              "wrong exception thrown from %s when passing null to %s parameter at index %s.%n"
                  + "Full parameters: %s%n"
                  + "Actual exception message: %s",
              invokable,
              invokable.getParameters().get(paramIndex).getType(),

  }

  /**
   * Performs {@link NullPointerTester} checks for all top-level classes in the package. For a class
   * {@code C}
   *
   * <ul>
   *   <li>All visible static methods are checked such that passing null for any parameter that's
   *       not annotated nullable (according to the rules of {@link NullPointerTester}) should throw
   *       {@link NullPointerException}.