• d-bugmail puremagic.com (62/62) Feb 29 2020 https://issues.dlang.org/show_bug.cgi?id=20623

d-bugmail puremagic.com writes:

https://issues.dlang.org/show_bug.cgi?id=20623

          Issue ID: 20623
           Summary: std.conv.to!string error when argument is an inout
                    float
           Product: D
           Version: D2
          Hardware: x86_64
                OS: Linux
            Status: NEW
          Severity: trivial
          Priority: P1
         Component: phobos
          Assignee: nobody puremagic.com
          Reporter: daniele.m.bondi gmail.com

import std.conv : to;

struct Foo
{
        float f = 0f;
        void foo() inout
        {
                to!string(this.f);
        }
}

void main()
{
        Foo().foo();
}


The above code causes these errors


/usr/include/dlang/dmd/std/math.d(282): Error: variable
std.math.floatTraits!(inout(float)).RECIP_EPSILON only parameters or stack
based variables can be inout
/usr/include/dlang/dmd/std/math.d(6814): Error: template instance
std.math.floatTraits!(inout(float)) error instantiating
/usr/include/dlang/dmd/std/format.d(2654):        instantiated from here:
isInfinity!(inout(float))
/usr/include/dlang/dmd/std/format.d(1875):        instantiated from here:
formatValueImpl!(Appender!string, inout(float), char)
/usr/include/dlang/dmd/std/conv.d(1072):        instantiated from here:
formatValue!(Appender!string, inout(float), char)
/usr/include/dlang/dmd/std/conv.d(222):        instantiated from here:
toImpl!(string, inout(float))
main.d(8):        instantiated from here: to!(inout(float))
/usr/include/dlang/dmd/std/format.d(2694): Error: template instance
std.math.signbit!(inout(float)) error instantiating
/usr/include/dlang/dmd/std/format.d(1875):        instantiated from here:
formatValueImpl!(Appender!string, inout(float), char)
/usr/include/dlang/dmd/std/conv.d(1072):        instantiated from here:
formatValue!(Appender!string, inout(float), char)
/usr/include/dlang/dmd/std/conv.d(222):        instantiated from here:
toImpl!(string, inout(float))
main.d(8):        instantiated from here: to!(inout(float))
/usr/include/dlang/dmd/std/format.d(2732): Error: forward reference to inferred
return type of function call function ()  trusted
{
import core.stdc.stdio : snprintf;
return snprintf(buf2.ptr, buf2.length, sprintfSpec.ptr, fs.width, fs.precision
== fs.UNSPECIFIED ? -1 : fs.precision, tval);
}
()


I tried adding Unqual! to the declaration of RECIP_EPSILON and the error seems
to go away

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