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Bug 35073 - Unexpected -Wunused-value with -std=c++17
Summary: Unexpected -Wunused-value with -std=c++17
Status: NEW
Alias: None
Product: clang
Classification: Unclassified
Component: -New Bugs (show other bugs)
Version: trunk
Hardware: PC Linux
: P enhancement
Assignee: Unassigned Clang Bugs
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2017-10-25 07:52 PDT by Stephan Bergmann
Modified: 2017-10-25 07:52 PDT (History)
1 user (show)

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Description Stephan Bergmann 2017-10-25 07:52:35 PDT 
At least with recent Clang trunk towards 6.0:

> $ cat test.cc
> struct B {};
> struct Ref { Ref(B *); };
> struct D: B { operator Ref() { return this; } };
> void f() { Ref(*new D); }
>
> $ clang++ -std=c++14 -fsyntax-only test.cc
>
> $ clang++ -std=c++17 -fsyntax-only test.cc
> test.cc:4:12: warning: expression result unused [-Wunused-value]
> void f() { Ref(*new D); }
>            ^   ~~~~~~
> 1 warning generated.