[clang-tidy] Exclude delegate constructors in cppcoreguidelines-prefe…

…r-member-initializer

As proposed by check fix would result in compilation error,
lets exclude delegate constructors from being checked.

Fixes: #52818

Reviewed By: ccotter

Differential Revision: https://reviews.llvm.org/D157242

clang-tools-extra/clang-tidy/cppcoreguidelines/PreferMemberInitializerCheck.cpp

@@ -141,10 +141,11 @@ void PreferMemberInitializerCheck::storeOptions(
 }
 
 void PreferMemberInitializerCheck::registerMatchers(MatchFinder *Finder) {
-  Finder->addMatcher(
-      cxxConstructorDecl(hasBody(compoundStmt()), unless(isInstantiated()))
-          .bind("ctor"),
-      this);
+  Finder->addMatcher(cxxConstructorDecl(hasBody(compoundStmt()),
+                                        unless(isInstantiated()),
+                                        unless(isDelegatingConstructor()))
+                         .bind("ctor"),
+                     this);
 }
 
 void PreferMemberInitializerCheck::check(

clang-tools-extra/docs/ReleaseNotes.rst

@@ -172,6 +172,10 @@ Changes in existing checks
   to ignore ``static`` variables declared within the scope of
   ``class``/``struct``.
 
+- Improved :doc:`cppcoreguidelines-prefer-member-initializer
+  <clang-tidy/checks/cppcoreguidelines/prefer-member-initializer>` check to
+  ignore delegate constructors.
+
 - Improved :doc:`llvm-namespace-comment
   <clang-tidy/checks/llvm/namespace-comment>` check to provide fixes for
   ``inline`` namespaces in the same format as :program:`clang-format`.

clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines/prefer-member-initializer.cpp

@@ -563,3 +563,10 @@ struct MacroCantFix {
     // CHECK-FIXES: ASSIGN_IN_MACRO(n, 0)
   }
 };
+
+struct PR52818  {
+    PR52818() : bar(5) {}
+    PR52818(int) : PR52818() { bar = 3; }
+
+    int bar;
+};