[patch, 3.4] Fix PR c++/20552

[Gabriel Dos Reis]

Volker Reichelt <reichelt@igpm.rwth-aachen.de> writes:

| The following patch fixes an ice-on-invalid-code on the 3.4 branch
| (see testcase below).
| 
| We didn't diagnose the error in the code and crashed later.
| The patch just removes the broken logic to prevent duplicate
| error messages.
| 
| The patch is a backport of a small part from Mark's patch
| http://gcc.gnu.org/ml/gcc-cvs/2004-03/msg00427.html
| (Don't let the cvs log message confuse you, it's wrong -
| read the ChangeLog instead.)
| 
| Bootstrapped and regtested on x86_64-unknown-linux-gnu.
| Ok for the 3.4 branch?
| Testcase OK for 4.0 branch up to mainline?

Yes all.

-- Gaby