Databases
StackOverflow2013
Postsdbo
POStrange error with a templated operator overload
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POStrange error with a templated operator overload
    primarykey
    data
    text
    <p>When I compile the following snippet, I get a compiler error with clang, but not with g++/MSVC:</p> <pre><code>#include &lt;string&gt; template&lt;typename T&gt; struct Const { explicit Const(T val) : value(val) {} T value; }; template&lt;typename T&gt; struct Var { explicit Var(const std::string &amp;n) : name(n) {} std::string name; }; template&lt;typename L, typename R&gt; struct Greater { Greater(L lhs, R rhs) : left(lhs), right(rhs) {} L left; R right; }; template&lt;typename L&gt; Greater&lt;L, Const&lt;int&gt; &gt; operator &gt; (L lhs, int rhs) { return Greater&lt;L, Const&lt;int&gt; &gt;(lhs, Const&lt;int&gt;(rhs)); } template&lt;typename R&gt; Greater&lt;Const&lt;int&gt;, R&gt; operator &gt; (int lhs, R rhs) { return Greater&lt;Const&lt;int&gt;, R&gt;(Const&lt;int&gt;(lhs), rhs); } Var&lt;double&gt; d("d"); int main() { d &gt; 10; return 0; } </code></pre> <p>The error reported is the following:</p> <pre><code>error: overloaded 'operator&gt;' must have at least one parameter of class or enumeration type Greater&lt;Const&lt;int&gt;, R&gt; operator &gt; (int lhs, R rhs) { ^ ./val.h:31:24: note: in instantiation of function template specialization 'operator&gt;&lt;int&gt;' requested here Greater&lt;Const&lt;int&gt;, R&gt; operator &gt; (int lhs, R rhs) { ^ 1 error generated. </code></pre> <p>which is about the operator function that is not used. If, instead, I write 10 > d instead of d > 10, then I get the same error about the other operator > function. The above compiles fine under gcc 4.4.6 and VS2012. What is my mistake ? </p> <p>Thank you. </p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USTemplateRex
    1. USJohn
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    3. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POStrange error with a templated operator overload
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POStrange error with a templated operator overload
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. POStrange error with a templated operator overload
      1. This table or related slice is empty.
      1. VTUpMod
    1. COIt compiles fine with gcc 4.8.1 too: http://ideone.com/wG4Yzv (C++98 mode) and http://ideone.com/8fwOWq (C++11 mode). What's your version of clang?
      singulars
      1. POStrange error with a templated operator overload
      1. USgx_
    2. CO@gx_ Just tried 3.1 and 3.2, both exhibit the problem.
      singulars
      1. POStrange error with a templated operator overload
      1. USBoBTFish
    3. CO@BoBTFish Thanks (too bad there's no "online Clang" (anymore)). I wonder about the very simplified example http://ideone.com/0Aooxo ? _Edit:_ oh wait, there's clang 3.0 at http://gcc.godbolt.org/ :) and my simplified example causes the same error. _Edit(2): Thanks again. Looks like a compiler bug..._
      singulars
      1. POStrange error with a templated operator overload
      1. USgx_
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload