## Concepts

The updated concepts implementation lives in the `concepts` branch.

Concepts are enabled using `-std=c++2a`, and Concepts TS functionality 
can be enabled using `-fconcepts-ts`. Note that the Concepts TS
functionality uses the semantics of the C++ Working Paper, so existing
code may compile differently than before.

Some differences:
- The grammar for requires-clauses changed when concepts were merged
  into the WP, so requirements like `requires !C<T>` must now be
  written as `requires (!C<T>)`.
- Abbreviated function templates and terse notation are not explicitly
  supported in the current working paper.
- There are some new regressions (yeah!).

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some of the runtime libraries, are under different terms; see the
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as HTML and plain text.  The source of this information is
gcc/doc/install.texi.  The installation information includes details
of what is included in the GCC sources and what files GCC installs.

See the file gcc/doc/gcc.texi (together with other files that it
includes) for usage and porting information.  An online readable
version of the manual is in the files gcc/doc/gcc.info*.

See http://gcc.gnu.org/bugs/ for how to report bugs usefully.

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