Summary and Info:
This is about editing PKGBUILD files with the included PKGBUILD.vim syntax for vim editor.
/usr/share/vim/vimfiles/syntax/PKGBUILD.vim

The vim syntax(colors) are broken if there is any closing parens inside quotes that would match the outside(of quotes) open parens.

Steps to Reproduce:
1. vim /tmp/PKGBUILD
2. paste these:

optdepends=( "chromium-pepper-flash-dev)" )
provides=('chromium-dev' 'chromedriver')

3. notice the `provides` line is now magenta, not yellow like `optdepends`
This is because of the closing parenthesis (the `dev)` part) inside the double quotes(though works with single quotes too) matches the open parens outside of the quotes (the `optdepends=(` part) ; also noting the fact that the closing parens(at end of line) doesn't match (using shift+5 on the parens to get to the matching one)

in a non PKGBUILD file, this seems to work ok, although in both files cursor under any closing parens match the outer start parens, the shift+5 action shows that the inner closing parens(inside double quotes) doesn't in the non PKGBUILD file.

4. this actually fails even if open and close parens are proper inside the quotes:
optdepends=("chromium-pepper-flash-dev()")

and now shift+5 works well, but the syntax colors are still messed up
(deducing that shift+5 works irrespective of syntax so is to be ignored here)

5. removing the parens inside the quotes fixes syntax highlighting

tested with latest pacman-git (commit d9cf14ff1d69ac8834b84015c7971f55ce77645b )