• d-bugmail puremagic.com (34/34) Apr 13 https://issues.dlang.org/show_bug.cgi?id=24499

d-bugmail puremagic.com writes:

https://issues.dlang.org/show_bug.cgi?id=24499

          Issue ID: 24499
           Summary: foreach over a ref parameter to an rvalue should be an
                    error
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: P1
         Component: dmd
          Assignee: nobody puremagic.com
          Reporter: bugzilla digitalmars.com

This should fail to compile:

 safe void test()
{
     foreach(ref el; 0 .. 5) el = 42;
}

It doesn't make any sense, and generates bad code:

0000:   55                       push      RBP
0001:   48 8B EC                 mov       RBP,RSP
0004:   48 83 EC 10              sub       RSP,010h
0008:   C7 45 F8 00 00 00 00     mov       dword ptr -8[RBP],0
000f:   C7 45 FC 05 00 00 00     mov       dword ptr -4[RBP],5
0016:   8B 45 F8                 mov       EAX,-8[RBP]
0019:   3B 45 FC                 cmp       EAX,-4[RBP]
001c:   7D 0C                    jge       L2a
001e:   C7 45 F8 2A 00 00 00     mov       dword ptr -8[RBP],02Ah !!!!!
0025:   FF 45 F8                 inc       dword ptr -8[RBP]
0028:   EB EC                    jmp short L16
002a:   C9                       leave
002b:   C3                       ret

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