[Issue 1753] New: String corruption in recursive CTFE functions

[d-bugmail at puremagic.com]

http://d.puremagic.com/issues/show_bug.cgi?id=1753

           Summary: String corruption in recursive CTFE functions
           Product: D
           Version: 1.024
          Platform: PC
        OS/Version: Windows
            Status: NEW
          Keywords: wrong-code
          Severity: major
          Priority: P2
         Component: DMD
        AssignedTo: bugzilla at digitalmars.com
        ReportedBy: clugdbug at yahoo.com.au


In the code below, the call to bar(foo("YYY", "A")) clobbers the old value of
f, (should be "A") with the return value of the function. Halfway through the
function, the value of f changes to be "@@@" ! This results in silent
generation of bad code.
I encountered this in BLADE. Took a long time to track this down, even longer
to reduce it. Further simplification is probably possible, but I'm sick of it
now <g>.

-----
char [] bar(char [] z)
{
    return z;
}

char[] foo(char [] a, char [] b) {    
        char [] f = a.length==1 ? a: foo("B", "C");
        if (a.length==1) assert(f.length==1); // OK
        char [] g = b.length==1 ? b: bar(foo("YYY", "A"));
        if (a.length==1) assert(f.length==1); // fails!
        return  "@@@";
}

const char [] xxx = foo("A", "xxx");
---------


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