http://d.puremagic.com/issues/show_bug.cgi?id=3746

           Summary: Misleding error message "OP  has no effect in
                    expression XXX), in void function
           Product: D
           Version: 2.041
          Platform: Other
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody@puremagic.com
        ReportedBy: baryluk@smp.if.uj.edu.pl


--- Comment #0 from Witold Baryluk <baryluk@smp.if.uj.edu.pl> 2010-01-27 17:15:05 PST ---
On function with void return type, if one will put expression after return:

void f() {
   auto a = 1, b = 3, c = 5;
   return a/b*c;
}


will end with compiler error like:

aaa.d(4): Error: * has no effect in expression (a / b * c)


My function "f" was lot bigger, and took me about 5 minutes to understand what is wrong.

Could such bugs can be detected and be something like

aaa.d(4): Error: no return statment allowed in void function/method

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Witold Baryluk <baryluk@smp.if.uj.edu.pl> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |minor


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Bernard Helyer <blood.of.life@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |blood.of.life@gmail.com


--- Comment #1 from Bernard Helyer <blood.of.life@gmail.com> 2010-01-27 19:59:24 PST ---
Well, obviously return *is* allowed from void functions (void f() { return; }). But 'error: return statement with a value in a void function' would be a preferable message than talking about values having no effect in expressions.

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--- Comment #2 from Witold Baryluk <baryluk@smp.if.uj.edu.pl> 2010-01-28 12:12:00 PST ---
(In reply to comment #1)
> Well, obviously return *is* allowed from void functions (void f() { return; }). But 'error: return statement with a value in a void function' would be a preferable message than talking about values having no effect in expressions.

Yes you are right. Error messages should be as precise as possible.

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yebblies <yebblies@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |sky@q1cc.net


--- Comment #3 from yebblies <yebblies@gmail.com> 2011-06-12 23:18:47 PDT ---
*** Issue 3855 has been marked as a duplicate of this issue. ***

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yebblies <yebblies@gmail.com> changed:

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


--- Comment #4 from yebblies <yebblies@gmail.com> 2011-06-12 23:19:46 PDT ---
*** This issue has been marked as a duplicate of issue 3630 ***

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yebblies <yebblies@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
         Resolution|DUPLICATE                   |
           Severity|minor                       |enhancement


--- Comment #5 from yebblies <yebblies@gmail.com> 2011-06-12 23:21:28 PDT ---
My bad, this is a request for a better error.

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bearophile_hugs@eml.cc changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bearophile_hugs@eml.cc


--- Comment #6 from bearophile_hugs@eml.cc 2011-06-13 03:21:08 PDT ---
*** Issue 3922 has been marked as a duplicate of this issue. ***

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--- Comment #7 from bearophile_hugs@eml.cc 2011-06-13 03:22:41 PDT ---
Issue 3922 contains some interesting comments.

It seems this enhancement request for a better error message has many dupes!

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yebblies <yebblies@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |patch
            Summary|Misleding error message "OP |Misleading error message
                   | has no effect in           |"OP  has no effect in
                   |expression XXX), in void    |expression XXX), in void
                   |function                    |function


--- Comment #8 from yebblies <yebblies@gmail.com> 2011-06-13 13:34:34 PDT ---
https://github.com/D-Programming-Language/dmd/pull/121

This adds the error message:
testx.d(4): Error: expression with no side effects used with void return

Good enough?

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