(isearch-error): New variable.
(isearch-invalid-regexp, isearch-within-brackets): Remove.
(isearch-error-state): Renamed from `isearch-invalid-regexp-state'.
(isearch-within-brackets-state): Remove.
(isearch-case-fold-search-state, isearch-pop-fun-state):
Decrease frame index.
(isearch-mode, isearch-top-state, isearch-push-state)
(isearch-edit-string, isearch-abort, isearch-search-and-update)
(isearch-fallback, isearch-message-prefix, isearch-message-suffix)
(isearch-search, isearch-lazy-highlight-new-loop):
Replace `isearch-invalid-regexp' with `isearch-error'.
Remove `isearch-within-brackets'.
(isearch-search): Add `search-failed' handler to `condition-case'.
(isearch-lazy-highlight-search): Add `condition-case' to catch
errors and allow `isearch-lazy-highlight-update' to try
highlighting from the beginning of the window.
(isearch-repeat): Move up code to set isearch-wrapped to t
before calling isearch-wrap-function.