1011 – illegal import declaration causes compile time segfault

-- a.d --
import b;
-- b.d --
import foo 0
dmd a.d
> b.d(1): ';' expected
> Segmentation fault
dmd b.d
> b.d(1): ';' expected
Program received signal SIGSEGV, Segmentation fault.
0x0000000000423610 in DsymbolTable::lookup (this=0x6118b0, ident=0x0) at 
dmd/dsymbol.c:858
858 sv = tab->lookup((char*)ident->string, ident->len);
Current language: auto; currently c++
(gdb) bt
#0 0x0000000000423610 in DsymbolTable::lookup (this=0x6118b0, ident=0x0) at 
dmd/dsymbol.c:858
#1 0x00000000004540d2 in Import::load (this=0x630360, sc=0x62fb10) at 
dmd/import.c:90
#2 0x00000000004542d1 in Import::semantic (this=0x630360, sc=0x62fb10) at 
dmd/import.c:120
#3 0x0000000000465aa9 in Module::semantic (this=0x62fea0) at dmd/module.c:652
#4 0x0000000000454229 in Import::load (this=0x61a1d0, sc=0x61a600) at 
dmd/import.c:110
#5 0x00000000004542d1 in Import::semantic (this=0x61a1d0, sc=0x61a600) at 
dmd/import.c:120
#6 0x0000000000465aa9 in Module::semantic (this=0x619cc0) at dmd/module.c:652
#7 0x00000000004640dc in main (argc=8, argv=0x619750) at dmd/mars.c:782

Added to DStress as
http://dstress.kuehne.cn/nocompile/i/import_19_A.d
http://dstress.kuehne.cn/nocompile/i/import_19_B.d 

Created attachment 326 [details] 
Patch against DMD 2.028
Import shouldn't do any semantic action if it doesn't know which module it's supposed to be importing. The error message I've added may be unnecessary; just returning would probably be OK.

Fixed DMD2.030 and DMD1.045.