compiler: better error for unexpected digit

A digit character is not invalid in general, but it's not permitted
at the start of an identifier.  Report a better error message.
The test case is issue11359.go in the source repo.

Change-Id: If8c55aba710419715a7932067023102f61efc742
Trust: Ian Lance Taylor <>
Reviewed-by: Than McIntosh <>
Reviewed-by: Cherry Zhang <>
1 file changed