llvm-project/clang
Eric Fiselier 73b51ae160 Add -Wctad-maybe-unsupported to diagnose CTAD on types with no user defined deduction guides.
Summary:
Some style guides want to allow using CTAD only on types that "opt-in"; i.e. on types that are designed to support it and not just types that *happen* to work with it.

This patch implements the `-Wctad-maybe-unsupported` warning, which is off by default, which warns when CTAD is used on a type that does not define any deduction guides.

The following pattern can be used to suppress the warning in cases where the type intentionally doesn't define any deduction guides:

```
struct allow_ctad_t;

template <class T>
struct TestSuppression {
  TestSuppression(T) {}
};
TestSuppression(allow_ctad_t)->TestSuppression<void>; // guides with incomplete parameter types are never considered.
```

Reviewers: rsmith, james.dennett, gromer

Reviewed By: rsmith

Subscribers: jdennett, Quuxplusone, lebedev.ri, cfe-commits

Differential Revision: https://reviews.llvm.org/D56731

llvm-svn: 351484
2019-01-17 21:44:24 +00:00
..
INPUTS
bindings [test] Disable Python binding tests w/ LLVM_ENABLE_PIC=OFF 2019-01-16 08:05:13 +00:00
cmake [CMake][Fuchsia] Disable modules for the second stage build 2019-01-17 04:12:30 +00:00
docs Bump the trunk version to 9.0.0svn 2019-01-16 10:57:02 +00:00
examples cmake: Remove uses of add_llvm_loadable_module macro 2018-12-20 22:04:36 +00:00
include Add -Wctad-maybe-unsupported to diagnose CTAD on types with no user defined deduction guides. 2019-01-17 21:44:24 +00:00
lib Add -Wctad-maybe-unsupported to diagnose CTAD on types with no user defined deduction guides. 2019-01-17 21:44:24 +00:00
runtime Fix check-hwasan with LLVM_BUILD_EXTERNAL_COMPILER_RT=ON 2019-01-03 22:50:45 +00:00
test Add -Wctad-maybe-unsupported to diagnose CTAD on types with no user defined deduction guides. 2019-01-17 21:44:24 +00:00
tools [analyzer][CrossTU][NFC] Generalize to external definitions instead of external functions 2019-01-10 17:44:04 +00:00
unittests Fix -Wsign-compare in new tests 2019-01-17 20:52:46 +00:00
utils Implement Attr dumping in terms of visitors 2019-01-11 19:16:01 +00:00
www Implementation Feature Test Macros for P0722R3 2019-01-11 17:09:22 +00:00
.arcconfig
.clang-format
.clang-tidy
.gitignore NFC: Add .vscode to .gitignore 2018-12-03 22:51:07 +00:00
CMakeLists.txt inhereit LLVM_ENABLE_LIBXML2 2018-11-29 14:57:14 +00:00
CODE_OWNERS.TXT Add myself as code owner for OpenBSD driver 2018-11-30 21:42:34 +00:00
INSTALL.txt
LICENSE.TXT Update year in license files 2019-01-15 15:10:32 +00:00
ModuleInfo.txt
NOTES.txt PTH-- Remove feature entirely- 2018-12-04 14:34:09 +00:00
README.txt

README.txt

//===----------------------------------------------------------------------===//
// C Language Family Front-end
//===----------------------------------------------------------------------===//

Welcome to Clang.  This is a compiler front-end for the C family of languages
(C, C++, Objective-C, and Objective-C++) which is built as part of the LLVM
compiler infrastructure project.

Unlike many other compiler frontends, Clang is useful for a number of things
beyond just compiling code: we intend for Clang to be host to a number of
different source-level tools.  One example of this is the Clang Static Analyzer.

If you're interested in more (including how to build Clang) it is best to read
the relevant web sites.  Here are some pointers:

Information on Clang:             http://clang.llvm.org/
Building and using Clang:         http://clang.llvm.org/get_started.html
Clang Static Analyzer:            http://clang-analyzer.llvm.org/
Information on the LLVM project:  http://llvm.org/

If you have questions or comments about Clang, a great place to discuss them is
on the Clang development mailing list:
  http://lists.llvm.org/mailman/listinfo/cfe-dev

If you find a bug in Clang, please file it in the LLVM bug tracker:
  http://llvm.org/bugs/