Bug: Accessing return value of type static array with length 1 or 2 by index.

John Colvin john.loughran.colvin at gmail.com
Sat Apr 20 08:11:42 PDT 2013


On Saturday, 20 April 2013 at 12:23:20 UTC, deed wrote:
> import std.stdio : writeln;
>
> template Template (uint n, T)
> {
>     T[n] statArr()
>     {
>         T[n] arr;
>         return arr;
>     }
>
>     T[] dynArr()
>     {
>         T[] dynArr = new T[n];
>         return dynArr;
>     }
> }
>
> void main()
> {
>     alias statArr9 = Template!(9, int).statArr;
>     alias statArr3 = Template!(3, int).statArr;
>     alias statArr2 = Template!(2, int).statArr;
>     alias statArr1 = Template!(1, int).statArr;
>     alias statArr0 = Template!(0, int).statArr;
>
>     // Fine
>     statArr9().writeln();       // Writes [0, 0, 0, 0, 0, 0, 0, 
> 0, 0]
>     statArr3().writeln();       // Writes [0, 0, 0]
>     statArr2().writeln();       // Writes [0, 0]
>     statArr1().writeln();       // Writes [0]
>     statArr0().writeln();       // Writes []
>
>     // 2 bugs
>     statArr9()[0].writeln();    // OK : Writes 0
>     statArr3()[0].writeln();    // OK : Writes 0
>     //statArr2()[0].writeln();  // BUG: Internal error: 
> ..\ztc\cgcs.c 344
>     //statArr1()[0].writeln();  // BUG: Internal error: 
> ..\ztc\cgcs.c 344
>     //statArr0()[0].writeln();  // OK : Error: array index 0 is 
> out of bounds
>                                 //      getArr0()[0 .. 0]
>
>
>     alias dynArr9 = Template!(9, int).dynArr;
>     alias dynArr3 = Template!(3, int).dynArr;
>     alias dynArr2 = Template!(2, int).dynArr;
>     alias dynArr1 = Template!(1, int).dynArr;
>     alias dynArr0 = Template!(0, int).dynArr;
>
>     dynArr9()[0].writeln();     // OK: Writes 0
>     dynArr3()[0].writeln();     // OK: Writes 0
>     dynArr2()[0].writeln();     // OK: Writes 0
>     dynArr1()[0].writeln();     // OK: Writes 0
>     //dynArr0()[0].writeln();   // OK: 
> core.exception.RangeError:
>                                 //     Range violation
>
>     // Other types
>     //Template!(2, bool).statArr()[0].writeln();    // BUG
>     //Template!(2, byte).statArr()[0].writeln();    // BUG
>     //Template!(2, ubyte).statArr()[0].writeln();   // BUG
>     //Template!(2, short).statArr()[0].writeln();   // BUG
>     //Template!(2, ushort).statArr()[0].writeln();  // BUG
>     //Template!(2, int).statArr()[0].writeln();     // BUG
>     //Template!(2, uint).statArr()[0].writeln();    // BUG
>     //Template!(2, long).statArr()[0].writeln();    // BUG
>     //Template!(2, ulong).statArr()[0].writeln();   // BUG
>     //Template!(2, float).statArr()[0].writeln();   // BUG
>     //Template!(2, double).statArr()[0].writeln();  // BUG
>     Template!(2, real).statArr()[0].writeln();      // OK : 
> Writes nan
>     //Template!(2, ifloat).statArr()[0].writeln();  // BUG
>     //Template!(2, idouble).statArr()[0].writeln(); // BUG
>     Template!(2, ireal).statArr()[0].writeln();     // OK : 
> Writes inan
>     //Template!(2, cfloat).statArr()[0].writeln();  // BUG
>     Template!(2, cdouble).statArr()[0].writeln();   // OK : 
> Writes nan+nani
>     Template!(2, creal).statArr()[0].writeln();     // OK : 
> Writes nan+nani
>     //Template!(2, char).statArr()[0].writeln();    // BUG
>     //Template!(2, wchar).statArr()[0].writeln();   // BUG
>     //Template!(2, dchar).statArr()[0].writeln();   // BUG
>
>     struct Sint     { int  a; }
>     struct Sreal    { real a; }
>     Template!(2, Sint).statArr()[0].writeln();      // OK : 
> Writes Sint(0)
>     Template!(2, Sreal).statArr()[0].writeln();     // OK : 
> Writes Sreal(nan)
> }
>
>
> Found in both dmd 2.061 and 2.062 for 32- and 64-bit. Other 
> types only tested with dmd 2.062.

btw: all the imaginary/complex builtin types will likely be 
deprecated at some point in the future. std.complex is the 
intended replacement


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