llvm dev - Sep 2020 - [clang-tidy] where are "clang-diagnostic" checkers

Hi, all,

	I build clang-tidy by "ninja clang-tidy", but when I run below
command, I get no checks. Where is the clang-diagnostic* checkers?  Thanks in
advance.
> $
/Users/zyg/Documents/workspace/llvm-project/llvm/cmake-build-debug/bin/clang-tidy
--checks="-*,clang-diagnostic-*" --list-checks
No checks enabled.

I have seen "clang-diagnostic-unreachable-code" when I use clang-tidy
7.0,  is it removed from latest clang-tidy?
> On Sep 27, 2020, at 6:27 PM, zhaoyonggang via llvm-dev <llvm-dev at
lists.llvm.org> wrote:
> 
> Hi, all,
> 
> 	I build clang-tidy by "ninja clang-tidy", but when I run below
command, I get no checks. Where is the clang-diagnostic* checkers?  Thanks in
advance.
> 
>> $
/Users/zyg/Documents/workspace/llvm-project/llvm/cmake-build-debug/bin/clang-tidy
--checks="-*,clang-diagnostic-*" --list-checks
> No checks enabled.
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev

Hi, Everyone

	My problem is how to check below code. How to add custom check for below code ?
Stmt(after(returnStmt))? Any clue is welcome, thanks


FYI , I have noted such issue can be checked by
"clang-diagnostic-unreachable-code" when I use clang-tidy 7(not so
sure). But currently I want to develop custom checker, and I clone latest llvm
repo and build clang-tidy. Clang-tidy I build can't find any issue.

	

```cpp
int16_t with_unreach( int16_t para) {
    int16_t local = 0;

    int* pt = nullptr;
    int a = *pt;
    switch (para) {
        local = para;
        // unreachable code
        case 1:{
            break;
        }

        default: {
            break;
        }
    }
    return para;
    para++;
    // unreachable code

}


```
> On Sep 27, 2020, at 7:30 PM, zhaoyonggang <yonggang.zhao at
icloud.com> wrote:
> 
> I have seen "clang-diagnostic-unreachable-code" when I use
clang-tidy 7.0,  is it removed from latest clang-tidy?
> 
>> On Sep 27, 2020, at 6:27 PM, zhaoyonggang via llvm-dev <llvm-dev at
lists.llvm.org> wrote:
>> 
>> Hi, all,
>> 
>> 	I build clang-tidy by "ninja clang-tidy", but when I run
below command, I get no checks. Where is the clang-diagnostic* checkers?  Thanks
in advance.
>> 
>>> $
/Users/zyg/Documents/workspace/llvm-project/llvm/cmake-build-debug/bin/clang-tidy
--checks="-*,clang-diagnostic-*" --list-checks
>> No checks enabled.
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> 
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Hi,

clang-diagnostic* doesn't refer to a group of checkers, they refer to
diagnostics emitted by clang during parsing and sema. 

If you want a full list of checks available you can run
`clang-tidy --checks=* --list-checks`

~Nathan
On Sun, 2020-09-27 at 18:27 +0800, zhaoyonggang via llvm-dev
wrote:
> Hi, all,
> 
> 	I build clang-tidy by "ninja clang-tidy", but when I run below
> command, I get no checks. Where is the clang-diagnostic*
> checkers?  Thanks in advance.
> 
> > $ /Users/zyg/Documents/workspace/llvm-project/llvm/cmake-build-
> > debug/bin/clang-tidy --checks="-*,clang-diagnostic-*"
--list-checks
> No checks enabled.
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev

Hi, Nathan

Thanks a lot.

When  I modify below code, and clang-diagnostic-unreachable-code warning will be
reported when I run
`/Users/zyg/Documents/workspace/llvm-project/llvm/cmake-build-debug/bin/clang-tidy
--checks=* ../library.cpp`. I still need to find how to enable "unreachable
code" warning by command option not by modifying code

--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -612,7 +612,7 @@ def warn_suggest_noreturn_block : Warning<
 // Unreachable code.
 def warn_unreachable : Warning<
   "code will never be executed">,
-  InGroup<UnreachableCode>, DefaultIgnore;
+  InGroup<UnreachableCode>;
 def warn_unreachable_break : Warning<
   "'break' will never be executed">,
   InGroup<UnreachableCodeBreak>, DefaultIgnore;
> On Sep 30, 2020, at 6:17 AM, Nathan James <n.james93 at
hotmail.co.uk> wrote:
> 
> Hi,
> 
> clang-diagnostic* doesn't refer to a group of checkers, they refer to
> diagnostics emitted by clang during parsing and sema. 
> 
> If you want a full list of checks available you can run
> `clang-tidy --checks=* --list-checks`
> 
> ~Nathan
> On Sun, 2020-09-27 at 18:27 +0800, zhaoyonggang via llvm-dev wrote:
>> Hi, all,
>> 
>> 	I build clang-tidy by "ninja clang-tidy", but when I run
below
>> command, I get no checks. Where is the clang-diagnostic*
>> checkers?  Thanks in advance.
>> 
>>> $ /Users/zyg/Documents/workspace/llvm-project/llvm/cmake-build-
>>> debug/bin/clang-tidy --checks="-*,clang-diagnostic-*"
--list-checks
>> No checks enabled.
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>