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

[zhaoyonggang via llvm-dev]

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.
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[zhaoyonggang via llvm-dev]

I have seen "clang-diagnostic-unreachable-code" when I use clang-tidy 7.0, is it removed from latest clang-tidy?

[zhaoyonggang via 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

}

```

[Nathan James via llvm-dev]

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

[zhaoyonggang via 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;