https://issues.dlang.org/show_bug.cgi?id=14186

ag0aep6g@gmail.com changed:

           What    |Removed                     |Added
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                 CC|                            |ag0aep6g@gmail.com

--- Comment #1 from ag0aep6g@gmail.com ---
I'm not well-versed in C/C++, but according to these pages:

http://www.gnu.org/software/gnu-c-manual/gnu-c-manual.html#Operator-Precedence
(points 13 and 14)
http://en.cppreference.com/w/cpp/language/operator_precedence#content (point
15)

it's C++ that deviated from C. Whereas D is line with C.

A little test with gcc and g++ seems to confirm that:

----
#include <stdio.h>
int main()
{
    int b = 1, c = 1;
    1 ? b : c = 0;
    printf("%d\n", b);
    return 0;
}
----

Compiling with gcc gives
----
test.c: In function ‘main’:
test.c:5:15: error: lvalue required as left operand of assignment
     1 ? b : c = 0;
               ^
----

Compiling with g++ succeeds, and running prints "1".

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https://issues.dlang.org/show_bug.cgi?id=14186

--- Comment #2 from Sobirari Muhomori <dfj1esp02@sneakemail.com> ---
Interesting, C99 and C11 don't allow for that:

assignment-expression:
  conditional-expression
  unary-expression assignment-operator assignment-expression

i.e. same precedence right-to-left associative.

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https://issues.dlang.org/show_bug.cgi?id=14186

--- Comment #3 from Sobirari Muhomori <dfj1esp02@sneakemail.com> ---
Can you confirm it with --std=c99 -pedantic?

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https://issues.dlang.org/show_bug.cgi?id=14186

--- Comment #4 from ag0aep6g@gmail.com ---
(In reply to Sobirari Muhomori from comment #3)
> Can you confirm it with --std=c99 -pedantic?

Same error:

----
$ gcc --std=c99 -pedantic test.c
test.c: In function ‘main’:
test.c:5:15: error: lvalue required as left operand of assignment
     1 ? b : c = 0;
               ^
$ gcc --version
gcc (Ubuntu 4.9.1-16ubuntu6) 4.9.1
----

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https://issues.dlang.org/show_bug.cgi?id=14186

--- Comment #5 from Sobirari Muhomori <dfj1esp02@sneakemail.com> ---
Looks like gcc has some history under this issue: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=6905

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https://issues.dlang.org/show_bug.cgi?id=14186

--- Comment #6 from ag0aep6g@gmail.com ---
(In reply to Sobirari Muhomori from comment #5)
> Looks like gcc has some history under this issue: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=6905

That ticket is about C++ though. But if C99 changed/clarified the operator precedence, gcc seems to be buggy in that regard.

For D that raises the question what version of C we're aiming for. K&R C, contemporary ANSI C, C as popular compilers understand it, ...?

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https://issues.dlang.org/show_bug.cgi?id=14186

yebblies <yebblies@gmail.com> changed:

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                 CC|                            |yebblies@gmail.com

--- Comment #7 from yebblies <yebblies@gmail.com> ---
A better option might be to make it a parse error, like we did with a < b < c.

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https://issues.dlang.org/show_bug.cgi?id=14186

Andrei Alexandrescu <andrei@erdani.com> changed:

           What    |Removed                     |Added
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            Version|D1 & D2                     |D2

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https://issues.dlang.org/show_bug.cgi?id=14186

Nick Treleaven <nick@geany.org> changed:

           What    |Removed                     |Added
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             Status|NEW                         |RESOLVED
                 CC|                            |nick@geany.org
         Resolution|---                         |DUPLICATE

--- Comment #8 from Nick Treleaven <nick@geany.org> ---
(In reply to ag0aep6g from comment #1)
>     int b = 1, c = 1;
>     1 ? b : c = 0;

The quoted code is now deprecated:

Deprecation: `1 ? b : c` must be surrounded by parentheses when next to operator `=`

*** This issue has been marked as a duplicate of issue 18743 ***

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