I have noticed several times weird errors where sketches that should
compile won't, and trivially moving parentheses around or breaking
statements up across lines, solves it. Here is an example.

void setup()
{
}

int testfunc(String conv)
{
return (int(conv));
}

will not compile, giving ' expecting RPAREN, found '(' ' whereas

void setup()
{
}

int testfunc(String conv)
{
return int(conv);
}

,will.

(I have included the setup function as also, a sketch won't compile for me
unless the return value of the first function is VOID- otherwise I get
'unexpected token', I don't know whether this is a bug or a feature)

*** This bug has been marked as a duplicate of 4 ***