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digitalmars.D.bugs - [Issue 3557] New: Pure function cannot call struct constructor

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=3557

           Summary: Pure function cannot call struct constructor
           Product: D
           Version: 2.036
          Platform: x86
        OS/Version: Windows
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: tomeksowi gmail.com



PST ---
struct A {
    float f;
    this (float f) {
        this.f = f;
    }
    static pure A stworz(float f) {
        return A(f);
    }
}

The above doesn't compile:
Error: pure function 'stworz' cannot call impure function 'this'

What's interesting, if stworz signature is one of the below:

static pure stworz(float f);
static pure auto stworz(float f);

then it merrily compiles. So it's sth about the explicit return type.

If I remove the constructor, it also compiles.
If A is a class, it also compiles.

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Nov 29 2009
next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=3557


Don <clugdbug yahoo.com.au> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |rejects-valid
                 CC|                            |clugdbug yahoo.com.au



It shouldn't compile, since the constructor isn't marked as pure. But if you
mark the constructor as pure:

 pure {
     this (float f) {
        this.f = f;
    }
 }

you get:
bug.d(14): Error: cannot modify const/immutable/inout expression this.f

So we definitely have a problem.

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Jan 10 2010
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=3557




PST ---


 It shouldn't compile, since the constructor isn't marked as pure. But if you
 mark the constructor as pure:
 
  pure {
      this (float f) {
         this.f = f;
     }
  }
 
 you get:
 bug.d(14): Error: cannot modify const/immutable/inout expression this.f
 
 So we definitely have a problem.


Yes, I had a feeling compiler should let me have pure ctors..

What about the problem I mentioned at the bottom (if A is a class):

class A {
    float f;
    this (float f) {    // NOT pure
        this.f = f;
    }
    static pure A stworz(float f) {
        return new A(f);
    }
}

This compiles. Should it?

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Jan 11 2010
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=3557




PST ---


 This compiles. Should it?


I'm now confident it shouldn't:

string global;
class A {
    float f;
    this (float f) {    // NOT pure
        this.f = f;
        global = "BUGABUGA!";
    }
    static pure A stworz(float f) {
        return new A(f);
    }
}

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Jan 11 2010
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=3557


Don <clugdbug yahoo.com.au> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|Pure function cannot call   |Struct constructors cannot
                   |struct constructor          |be declared as pure







 This compiles. Should it?


 
 I'm now confident it shouldn't:
 
 string global;
 class A {
     float f;
     this (float f) {    // NOT pure
         this.f = f;
         global = "BUGABUGA!";
     }
     static pure A stworz(float f) {
         return new A(f);
     }
 }


That's bug 3573.

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Jan 12 2010
prev sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=3557


yebblies <yebblies gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |yebblies gmail.com
         Resolution|                            |FIXED



Marking constructors as pure works in current dmd (2.054).

I've put the other case as Issue 6320

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Jul 14 2011