[clang-tools-extra] [clang-tidy] Fix FP on cppcoreguidelines-pro-type-member-init with forward decl (PR #190521)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang-tools-extra

Author: Baranov Victor (vbvictor)

<details>
<summary>Changes</summary>

Fixes https://github.com/llvm/llvm-project/issues/155416.

---
Full diff: https://github.com/llvm/llvm-project/pull/190521.diff


3 Files Affected:

- (modified) clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp (+2-1) 
- (modified) clang-tools-extra/docs/ReleaseNotes.rst (+5) 
- (modified) clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-type-member-init.cpp (+24) 


``````````diff
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp
index a259d03724d24..07d71968a07b8 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProTypeMemberInitCheck.cpp
@@ -572,7 +572,8 @@ void ProTypeMemberInitCheck::checkMissingBaseClassInitializer(
 
     for (const CXXCtorInitializer *Init : Ctor->inits())
       if (Init->isBaseInitializer() && Init->isWritten())
-        BasesToInit.erase(Init->getBaseClass()->getAsCXXRecordDecl());
+        BasesToInit.erase(
+            Init->getBaseClass()->getAsCXXRecordDecl()->getCanonicalDecl());
   }
 
   if (BasesToInit.empty())
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 69dc5b9633398..5ba16e1f71a10 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -283,6 +283,11 @@ Changes in existing checks
   <clang-tidy/checks/cppcoreguidelines/missing-std-forward>` check by fixing
   a false positive for constrained template parameters.
 
+- Improved :doc:`cppcoreguidelines-pro-type-member-init
+  <clang-tidy/checks/cppcoreguidelines/pro-type-member-init>` check by fixing
+  a false positive when a base class has a forward declaration before its
+  definition.
+
 - Improved :doc:`cppcoreguidelines-pro-type-vararg
   <clang-tidy/checks/cppcoreguidelines/pro-type-vararg>` check by no longer
   warning on builtins with custom type checking (e.g., type-generic builtins
diff --git a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-type-member-init.cpp b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-type-member-init.cpp
index 890d1d262066b..7468ce04434b0 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-type-member-init.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/pro-type-member-init.cpp
@@ -611,3 +611,27 @@ namespace PR37250 {
   const V v;
   const S s{v};
 }
+
+namespace PR155416 {
+  struct S;
+
+  struct S {
+    int a;
+  };
+
+  struct C : S {
+    C() : S{0} {}
+  };
+
+  template<typename T>
+  struct St;
+
+  template<typename T>
+  struct St{
+    T a;
+  };
+
+  struct Ct : St<int> {
+    Ct() : St{0} {}
+  };
+}

``````````

</details>


https://github.com/llvm/llvm-project/pull/190521