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Merged
zeyi2 merged 2 commits into from
Dec 13, 2025
Merged

[clang-tidy] Moved Multiple Inheritence check from fuchsia to misc module #171565

zeyi2 merged 2 commits into from
Dec 13, 2025
+82 −60

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@Bhuvan1527
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@Bhuvan1527 Bhuvan1527 commented Dec 10, 2025

Resolves: #171136

Referred the issue tagged in the issue mentioned.

@llvmbot
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llvmbot commented Dec 10, 2025

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

Author: Bala_Bhuvan_Varma (Bhuvan1527)

Changes

Resolves: #171136

Referred the issue tagged in the issue mentioned.

Full diff: https://github.com/llvm/llvm-project/pull/171565.diff

7 Files Affected:

  • (modified) clang-tools-extra/clang-tidy/fuchsia/CMakeLists.txt (-1)
  • (modified) clang-tools-extra/clang-tidy/fuchsia/FuchsiaTidyModule.cpp (+2-2)
  • (modified) clang-tools-extra/clang-tidy/misc/CMakeLists.txt (+1)
  • (modified) clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp (+3)
  • (renamed) clang-tools-extra/clang-tidy/misc/MultipleInheritanceCheck.cpp (+2-2)
  • (renamed) clang-tools-extra/clang-tidy/misc/MultipleInheritanceCheck.h (+5-5)
  • (added) clang-tools-extra/test/clang-tidy/checkers/misc/multiple-inheritance.cpp (+165)
diff --git a/clang-tools-extra/clang-tidy/fuchsia/CMakeLists.txt b/clang-tools-extra/clang-tidy/fuchsia/CMakeLists.txt
index c7234098f094a..b7e278814371e 100644
--- a/clang-tools-extra/clang-tidy/fuchsia/CMakeLists.txt
+++ b/clang-tools-extra/clang-tidy/fuchsia/CMakeLists.txt
@@ -7,7 +7,6 @@ add_clang_library(clangTidyFuchsiaModule STATIC
   DefaultArgumentsCallsCheck.cpp
   DefaultArgumentsDeclarationsCheck.cpp
   FuchsiaTidyModule.cpp
-  MultipleInheritanceCheck.cpp
   OverloadedOperatorCheck.cpp
   StaticallyConstructedObjectsCheck.cpp
   TemporaryObjectsCheck.cpp
diff --git a/clang-tools-extra/clang-tidy/fuchsia/FuchsiaTidyModule.cpp b/clang-tools-extra/clang-tidy/fuchsia/FuchsiaTidyModule.cpp
index c62c43f0c42a3..6cbae3253f53c 100644
--- a/clang-tools-extra/clang-tidy/fuchsia/FuchsiaTidyModule.cpp
+++ b/clang-tools-extra/clang-tidy/fuchsia/FuchsiaTidyModule.cpp
@@ -12,7 +12,7 @@
 #include "../google/UnnamedNamespaceInHeaderCheck.h"
 #include "DefaultArgumentsCallsCheck.h"
 #include "DefaultArgumentsDeclarationsCheck.h"
-#include "MultipleInheritanceCheck.h"
+#include "../misc/MultipleInheritanceCheck.h"
 #include "OverloadedOperatorCheck.h"
 #include "StaticallyConstructedObjectsCheck.h"
 #include "TemporaryObjectsCheck.h"
@@ -34,7 +34,7 @@ class FuchsiaModule : public ClangTidyModule {
         "fuchsia-default-arguments-declarations");
     CheckFactories.registerCheck<google::build::UnnamedNamespaceInHeaderCheck>(
         "fuchsia-header-anon-namespaces");
-    CheckFactories.registerCheck<MultipleInheritanceCheck>(
+    CheckFactories.registerCheck<misc::MultipleInheritanceCheck>(
         "fuchsia-multiple-inheritance");
     CheckFactories.registerCheck<OverloadedOperatorCheck>(
         "fuchsia-overloaded-operator");
diff --git a/clang-tools-extra/clang-tidy/misc/CMakeLists.txt b/clang-tools-extra/clang-tidy/misc/CMakeLists.txt
index e8705aada3f22..c05930cc27ce0 100644
--- a/clang-tools-extra/clang-tidy/misc/CMakeLists.txt
+++ b/clang-tools-extra/clang-tidy/misc/CMakeLists.txt
@@ -27,6 +27,7 @@ add_clang_library(clangTidyMiscModule STATIC
   MiscTidyModule.cpp
   MisleadingBidirectionalCheck.cpp
   MisleadingIdentifierCheck.cpp
+  MultipleInheritanceCheck.cpp
   MisplacedConstCheck.cpp
   NewDeleteOverloadsCheck.cpp
   NoRecursionCheck.cpp
diff --git a/clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp b/clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp
index 03f25775de0bf..9d48f2005edae 100644
--- a/clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp
+++ b/clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp
@@ -17,6 +17,7 @@
 #include "IncludeCleanerCheck.h"
 #include "MisleadingBidirectionalCheck.h"
 #include "MisleadingIdentifierCheck.h"
+#include "MultipleInheritanceCheck.h"
 #include "MisplacedConstCheck.h"
 #include "NewDeleteOverloadsCheck.h"
 #include "NoRecursionCheck.h"
@@ -86,6 +87,8 @@ class MiscModule : public ClangTidyModule {
         "misc-use-anonymous-namespace");
     CheckFactories.registerCheck<UseInternalLinkageCheck>(
         "misc-use-internal-linkage");
+    CheckFactories.registerCheck<MultipleInheritanceCheck>(
+        "misc-multiple-inheritance");
   }
 };
 
diff --git a/clang-tools-extra/clang-tidy/fuchsia/MultipleInheritanceCheck.cpp b/clang-tools-extra/clang-tidy/misc/MultipleInheritanceCheck.cpp
similarity index 97%
rename from clang-tools-extra/clang-tidy/fuchsia/MultipleInheritanceCheck.cpp
rename to clang-tools-extra/clang-tidy/misc/MultipleInheritanceCheck.cpp
index 4a10cb4085a41..557b4559697b9 100644
--- a/clang-tools-extra/clang-tidy/fuchsia/MultipleInheritanceCheck.cpp
+++ b/clang-tools-extra/clang-tidy/misc/MultipleInheritanceCheck.cpp
@@ -13,7 +13,7 @@
 using namespace clang;
 using namespace clang::ast_matchers;
 
-namespace clang::tidy::fuchsia {
+namespace clang::tidy::misc {
 
 namespace {
 AST_MATCHER(CXXRecordDecl, hasBases) {
@@ -74,4 +74,4 @@ void MultipleInheritanceCheck::check(const MatchFinder::MatchResult &Result) {
                           "pure virtual is discouraged");
 }
 
-} // namespace clang::tidy::fuchsia
+} // namespace clang::tidy::misc
diff --git a/clang-tools-extra/clang-tidy/fuchsia/MultipleInheritanceCheck.h b/clang-tools-extra/clang-tidy/misc/MultipleInheritanceCheck.h
similarity index 82%
rename from clang-tools-extra/clang-tidy/fuchsia/MultipleInheritanceCheck.h
rename to clang-tools-extra/clang-tidy/misc/MultipleInheritanceCheck.h
index 4dcbd0c7893c5..5fe1cf7c321c4 100644
--- a/clang-tools-extra/clang-tidy/fuchsia/MultipleInheritanceCheck.h
+++ b/clang-tools-extra/clang-tidy/misc/MultipleInheritanceCheck.h
@@ -6,12 +6,12 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_FUCHSIA_MULTIPLEINHERITANCECHECK_H
-#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_FUCHSIA_MULTIPLEINHERITANCECHECK_H
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_MULTIPLEINHERITANCECHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_MULTIPLEINHERITANCECHECK_H
 
 #include "../ClangTidyCheck.h"
 
-namespace clang::tidy::fuchsia {
+namespace clang::tidy::misc {
 
 /// Multiple implementation inheritance is discouraged.
 ///
@@ -38,6 +38,6 @@ class MultipleInheritanceCheck : public ClangTidyCheck {
   llvm::DenseMap<const CXXRecordDecl *, bool> InterfaceMap;
 };
 
-} // namespace clang::tidy::fuchsia
+} // namespace clang::tidy::misc
 
-#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_FUCHSIA_MULTIPLEINHERITANCECHECK_H
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_MULTIPLEINHERITANCECHECK_H
diff --git a/clang-tools-extra/test/clang-tidy/checkers/misc/multiple-inheritance.cpp b/clang-tools-extra/test/clang-tidy/checkers/misc/multiple-inheritance.cpp
new file mode 100644
index 0000000000000..6004ab3d812ea
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/misc/multiple-inheritance.cpp
@@ -0,0 +1,165 @@
+// RUN: %check_clang_tidy %s misc-multiple-inheritance %t
+
+class Base_A {
+public:
+  virtual int foo() { return 0; }
+};
+
+class Base_B {
+public:
+  virtual int bar() { return 0; }
+};
+
+class Base_A_child : public Base_A {
+public:
+  virtual int baz() { return 0; }
+};
+
+class Interface_A {
+public:
+  virtual int foo() = 0;
+};
+
+class Interface_B {
+public:
+  virtual int bar() = 0;
+};
+
+class Interface_C {
+public:
+  virtual int blat() = 0;
+};
+
+class Interface_A_with_member {
+public:
+  virtual int foo() = 0;
+  int val = 0;
+};
+
+class Interface_with_A_Parent : public Base_A {
+public:
+  virtual int baz() = 0;
+};
+
+// Shouldn't warn on forward declarations.
+class Bad_Child1;
+
+// Inherits from multiple concrete classes.
+// CHECK-MESSAGES: [[@LINE+2]]:1: warning: inheriting multiple classes that aren't pure virtual is discouraged [misc-multiple-inheritance]
+// CHECK-NEXT: class Bad_Child1 : public Base_A, Base_B {};
+class Bad_Child1 : public Base_A, Base_B {};
+
+// CHECK-MESSAGES: [[@LINE+1]]:1: warning: inheriting multiple classes that aren't pure virtual is discouraged [misc-multiple-inheritance]
+class Bad_Child2 : public Base_A, Interface_A_with_member {
+  virtual int foo() override { return 0; }
+};
+
+// CHECK-MESSAGES: [[@LINE+2]]:1: warning: inheriting multiple classes that aren't pure virtual is discouraged [misc-multiple-inheritance]
+// CHECK-NEXT: class Bad_Child3 : public Interface_with_A_Parent, Base_B {
+class Bad_Child3 : public Interface_with_A_Parent, Base_B {
+  virtual int baz() override { return 0; }
+};
+
+// Easy cases of single inheritance
+class Simple_Child1 : public Base_A {};
+class Simple_Child2 : public Interface_A {
+  virtual int foo() override { return 0; }
+};
+
+// Valid uses of multiple inheritance
+class Good_Child1 : public Interface_A, Interface_B {
+  virtual int foo() override { return 0; }
+  virtual int bar() override { return 0; }
+};
+
+class Good_Child2 : public Base_A, Interface_B {
+  virtual int bar() override { return 0; }
+};
+
+class Good_Child3 : public Base_A_child, Interface_C, Interface_B {
+  virtual int bar() override { return 0; }
+  virtual int blat() override { return 0; }
+};
+
+struct B1 { int x; };
+struct B2 { int x;};
+// CHECK-MESSAGES: [[@LINE+2]]:1: warning: inheriting multiple classes that aren't pure virtual is discouraged [misc-multiple-inheritance]
+// CHECK-NEXT: struct D : B1, B2 {};
+struct D1 : B1, B2 {};
+
+struct Base1 { virtual void foo() = 0; };
+struct V1 : virtual Base1 {};
+struct V2 : virtual Base1 {};
+struct D2 : V1, V2 {};
+
+struct Base2 { virtual void foo(); };
+struct V3 : virtual Base2 {};
+struct V4 : virtual Base2 {};
+struct D3 : V3, V4 {};
+
+struct Base3 {};
+struct V5 : virtual Base3 { virtual void f(); };
+struct V6 : virtual Base3 { virtual void g(); };
+// CHECK-MESSAGES: [[@LINE+2]]:1: warning: inheriting multiple classes that aren't pure virtual is discouraged [misc-multiple-inheritance]
+// CHECK-NEXT: struct D4 : V5, V6 {};
+struct D4 : V5, V6 {};
+
+struct Base4 {};
+struct V7 : virtual Base4 { virtual void f() = 0; };
+struct V8 : virtual Base4 { virtual void g() = 0; };
+struct D5 : V7, V8 {};
+
+struct Base5 { virtual void f() = 0; };
+struct V9 : virtual Base5 { virtual void f(); };
+struct V10 : virtual Base5 { virtual void g() = 0; };
+struct D6 : V9, V10 {};
+
+struct Base6 { virtual void f(); };
+struct Base7 { virtual void g(); };
+struct V15 : virtual Base6 { virtual void f() = 0; };
+struct V16 : virtual Base7 { virtual void g() = 0; };
+// CHECK-MESSAGES: [[@LINE+2]]:1: warning: inheriting multiple classes that aren't pure virtual is discouraged [misc-multiple-inheritance]
+// CHECK-NEXT: struct D9 : V15, V16 {};
+struct D9 : V15, V16 {};
+
+struct Static_Base { static void foo(); };
+struct V11 : virtual Static_Base {};
+struct V12 : virtual Static_Base {};
+struct D7 : V11, V12 {};
+
+struct Static_Base_2 {};
+struct V13 : virtual Static_Base_2 { static void f(); };
+struct V14 : virtual Static_Base_2 { static void g(); };
+struct D8 : V13, V14 {};
+
+template<typename T> struct A : T {};
+template<typename T> struct B : virtual T {};
+
+template<typename> struct C {};
+template<typename T> struct D : C<T> {};
+
+// Check clang_tidy does not crash on this code.
+template <class T>
+struct WithTemplBase : T {
+  WithTemplBase();
+};
+
+void test_no_crash() {
+  auto foo = []() {};
+  WithTemplBase<decltype(foo)>();
+}
+
+struct S1 {};
+struct S2 {};
+
+struct S3 : S1, S2 {};
+
+namespace N {
+
+struct S1 { int i; };
+struct S2 { int i; };
+
+// CHECK-MESSAGES: [[@LINE+1]]:1: warning: inheriting multiple classes that aren't pure virtual is discouraged [misc-multiple-inheritance]
+struct S3 : S1, S2 {};
+
+} // namespace N

@llvmbot
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llvmbot commented Dec 10, 2025

@llvm/pr-subscribers-clang-tidy

Author: Bala_Bhuvan_Varma (Bhuvan1527)

Changes

Resolves: #171136

Referred the issue tagged in the issue mentioned.

Full diff: https://github.com/llvm/llvm-project/pull/171565.diff

7 Files Affected:

  • (modified) clang-tools-extra/clang-tidy/fuchsia/CMakeLists.txt (-1)
  • (modified) clang-tools-extra/clang-tidy/fuchsia/FuchsiaTidyModule.cpp (+2-2)
  • (modified) clang-tools-extra/clang-tidy/misc/CMakeLists.txt (+1)
  • (modified) clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp (+3)
  • (renamed) clang-tools-extra/clang-tidy/misc/MultipleInheritanceCheck.cpp (+2-2)
  • (renamed) clang-tools-extra/clang-tidy/misc/MultipleInheritanceCheck.h (+5-5)
  • (added) clang-tools-extra/test/clang-tidy/checkers/misc/multiple-inheritance.cpp (+165)
diff --git a/clang-tools-extra/clang-tidy/fuchsia/CMakeLists.txt b/clang-tools-extra/clang-tidy/fuchsia/CMakeLists.txt
index c7234098f094a..b7e278814371e 100644
--- a/clang-tools-extra/clang-tidy/fuchsia/CMakeLists.txt
+++ b/clang-tools-extra/clang-tidy/fuchsia/CMakeLists.txt
@@ -7,7 +7,6 @@ add_clang_library(clangTidyFuchsiaModule STATIC
   DefaultArgumentsCallsCheck.cpp
   DefaultArgumentsDeclarationsCheck.cpp
   FuchsiaTidyModule.cpp
-  MultipleInheritanceCheck.cpp
   OverloadedOperatorCheck.cpp
   StaticallyConstructedObjectsCheck.cpp
   TemporaryObjectsCheck.cpp
diff --git a/clang-tools-extra/clang-tidy/fuchsia/FuchsiaTidyModule.cpp b/clang-tools-extra/clang-tidy/fuchsia/FuchsiaTidyModule.cpp
index c62c43f0c42a3..6cbae3253f53c 100644
--- a/clang-tools-extra/clang-tidy/fuchsia/FuchsiaTidyModule.cpp
+++ b/clang-tools-extra/clang-tidy/fuchsia/FuchsiaTidyModule.cpp
@@ -12,7 +12,7 @@
 #include "../google/UnnamedNamespaceInHeaderCheck.h"
 #include "DefaultArgumentsCallsCheck.h"
 #include "DefaultArgumentsDeclarationsCheck.h"
-#include "MultipleInheritanceCheck.h"
+#include "../misc/MultipleInheritanceCheck.h"
 #include "OverloadedOperatorCheck.h"
 #include "StaticallyConstructedObjectsCheck.h"
 #include "TemporaryObjectsCheck.h"
@@ -34,7 +34,7 @@ class FuchsiaModule : public ClangTidyModule {
         "fuchsia-default-arguments-declarations");
     CheckFactories.registerCheck<google::build::UnnamedNamespaceInHeaderCheck>(
         "fuchsia-header-anon-namespaces");
-    CheckFactories.registerCheck<MultipleInheritanceCheck>(
+    CheckFactories.registerCheck<misc::MultipleInheritanceCheck>(
         "fuchsia-multiple-inheritance");
     CheckFactories.registerCheck<OverloadedOperatorCheck>(
         "fuchsia-overloaded-operator");
diff --git a/clang-tools-extra/clang-tidy/misc/CMakeLists.txt b/clang-tools-extra/clang-tidy/misc/CMakeLists.txt
index e8705aada3f22..c05930cc27ce0 100644
--- a/clang-tools-extra/clang-tidy/misc/CMakeLists.txt
+++ b/clang-tools-extra/clang-tidy/misc/CMakeLists.txt
@@ -27,6 +27,7 @@ add_clang_library(clangTidyMiscModule STATIC
   MiscTidyModule.cpp
   MisleadingBidirectionalCheck.cpp
   MisleadingIdentifierCheck.cpp
+  MultipleInheritanceCheck.cpp
   MisplacedConstCheck.cpp
   NewDeleteOverloadsCheck.cpp
   NoRecursionCheck.cpp
diff --git a/clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp b/clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp
index 03f25775de0bf..9d48f2005edae 100644
--- a/clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp
+++ b/clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp
@@ -17,6 +17,7 @@
 #include "IncludeCleanerCheck.h"
 #include "MisleadingBidirectionalCheck.h"
 #include "MisleadingIdentifierCheck.h"
+#include "MultipleInheritanceCheck.h"
 #include "MisplacedConstCheck.h"
 #include "NewDeleteOverloadsCheck.h"
 #include "NoRecursionCheck.h"
@@ -86,6 +87,8 @@ class MiscModule : public ClangTidyModule {
         "misc-use-anonymous-namespace");
     CheckFactories.registerCheck<UseInternalLinkageCheck>(
         "misc-use-internal-linkage");
+    CheckFactories.registerCheck<MultipleInheritanceCheck>(
+        "misc-multiple-inheritance");
   }
 };
 
diff --git a/clang-tools-extra/clang-tidy/fuchsia/MultipleInheritanceCheck.cpp b/clang-tools-extra/clang-tidy/misc/MultipleInheritanceCheck.cpp
similarity index 97%
rename from clang-tools-extra/clang-tidy/fuchsia/MultipleInheritanceCheck.cpp
rename to clang-tools-extra/clang-tidy/misc/MultipleInheritanceCheck.cpp
index 4a10cb4085a41..557b4559697b9 100644
--- a/clang-tools-extra/clang-tidy/fuchsia/MultipleInheritanceCheck.cpp
+++ b/clang-tools-extra/clang-tidy/misc/MultipleInheritanceCheck.cpp
@@ -13,7 +13,7 @@
 using namespace clang;
 using namespace clang::ast_matchers;
 
-namespace clang::tidy::fuchsia {
+namespace clang::tidy::misc {
 
 namespace {
 AST_MATCHER(CXXRecordDecl, hasBases) {
@@ -74,4 +74,4 @@ void MultipleInheritanceCheck::check(const MatchFinder::MatchResult &Result) {
                           "pure virtual is discouraged");
 }
 
-} // namespace clang::tidy::fuchsia
+} // namespace clang::tidy::misc
diff --git a/clang-tools-extra/clang-tidy/fuchsia/MultipleInheritanceCheck.h b/clang-tools-extra/clang-tidy/misc/MultipleInheritanceCheck.h
similarity index 82%
rename from clang-tools-extra/clang-tidy/fuchsia/MultipleInheritanceCheck.h
rename to clang-tools-extra/clang-tidy/misc/MultipleInheritanceCheck.h
index 4dcbd0c7893c5..5fe1cf7c321c4 100644
--- a/clang-tools-extra/clang-tidy/fuchsia/MultipleInheritanceCheck.h
+++ b/clang-tools-extra/clang-tidy/misc/MultipleInheritanceCheck.h
@@ -6,12 +6,12 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_FUCHSIA_MULTIPLEINHERITANCECHECK_H
-#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_FUCHSIA_MULTIPLEINHERITANCECHECK_H
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_MULTIPLEINHERITANCECHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_MULTIPLEINHERITANCECHECK_H
 
 #include "../ClangTidyCheck.h"
 
-namespace clang::tidy::fuchsia {
+namespace clang::tidy::misc {
 
 /// Multiple implementation inheritance is discouraged.
 ///
@@ -38,6 +38,6 @@ class MultipleInheritanceCheck : public ClangTidyCheck {
   llvm::DenseMap<const CXXRecordDecl *, bool> InterfaceMap;
 };
 
-} // namespace clang::tidy::fuchsia
+} // namespace clang::tidy::misc
 
-#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_FUCHSIA_MULTIPLEINHERITANCECHECK_H
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_MULTIPLEINHERITANCECHECK_H
diff --git a/clang-tools-extra/test/clang-tidy/checkers/misc/multiple-inheritance.cpp b/clang-tools-extra/test/clang-tidy/checkers/misc/multiple-inheritance.cpp
new file mode 100644
index 0000000000000..6004ab3d812ea
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/misc/multiple-inheritance.cpp
@@ -0,0 +1,165 @@
+// RUN: %check_clang_tidy %s misc-multiple-inheritance %t
+
+class Base_A {
+public:
+  virtual int foo() { return 0; }
+};
+
+class Base_B {
+public:
+  virtual int bar() { return 0; }
+};
+
+class Base_A_child : public Base_A {
+public:
+  virtual int baz() { return 0; }
+};
+
+class Interface_A {
+public:
+  virtual int foo() = 0;
+};
+
+class Interface_B {
+public:
+  virtual int bar() = 0;
+};
+
+class Interface_C {
+public:
+  virtual int blat() = 0;
+};
+
+class Interface_A_with_member {
+public:
+  virtual int foo() = 0;
+  int val = 0;
+};
+
+class Interface_with_A_Parent : public Base_A {
+public:
+  virtual int baz() = 0;
+};
+
+// Shouldn't warn on forward declarations.
+class Bad_Child1;
+
+// Inherits from multiple concrete classes.
+// CHECK-MESSAGES: [[@LINE+2]]:1: warning: inheriting multiple classes that aren't pure virtual is discouraged [misc-multiple-inheritance]
+// CHECK-NEXT: class Bad_Child1 : public Base_A, Base_B {};
+class Bad_Child1 : public Base_A, Base_B {};
+
+// CHECK-MESSAGES: [[@LINE+1]]:1: warning: inheriting multiple classes that aren't pure virtual is discouraged [misc-multiple-inheritance]
+class Bad_Child2 : public Base_A, Interface_A_with_member {
+  virtual int foo() override { return 0; }
+};
+
+// CHECK-MESSAGES: [[@LINE+2]]:1: warning: inheriting multiple classes that aren't pure virtual is discouraged [misc-multiple-inheritance]
+// CHECK-NEXT: class Bad_Child3 : public Interface_with_A_Parent, Base_B {
+class Bad_Child3 : public Interface_with_A_Parent, Base_B {
+  virtual int baz() override { return 0; }
+};
+
+// Easy cases of single inheritance
+class Simple_Child1 : public Base_A {};
+class Simple_Child2 : public Interface_A {
+  virtual int foo() override { return 0; }
+};
+
+// Valid uses of multiple inheritance
+class Good_Child1 : public Interface_A, Interface_B {
+  virtual int foo() override { return 0; }
+  virtual int bar() override { return 0; }
+};
+
+class Good_Child2 : public Base_A, Interface_B {
+  virtual int bar() override { return 0; }
+};
+
+class Good_Child3 : public Base_A_child, Interface_C, Interface_B {
+  virtual int bar() override { return 0; }
+  virtual int blat() override { return 0; }
+};
+
+struct B1 { int x; };
+struct B2 { int x;};
+// CHECK-MESSAGES: [[@LINE+2]]:1: warning: inheriting multiple classes that aren't pure virtual is discouraged [misc-multiple-inheritance]
+// CHECK-NEXT: struct D : B1, B2 {};
+struct D1 : B1, B2 {};
+
+struct Base1 { virtual void foo() = 0; };
+struct V1 : virtual Base1 {};
+struct V2 : virtual Base1 {};
+struct D2 : V1, V2 {};
+
+struct Base2 { virtual void foo(); };
+struct V3 : virtual Base2 {};
+struct V4 : virtual Base2 {};
+struct D3 : V3, V4 {};
+
+struct Base3 {};
+struct V5 : virtual Base3 { virtual void f(); };
+struct V6 : virtual Base3 { virtual void g(); };
+// CHECK-MESSAGES: [[@LINE+2]]:1: warning: inheriting multiple classes that aren't pure virtual is discouraged [misc-multiple-inheritance]
+// CHECK-NEXT: struct D4 : V5, V6 {};
+struct D4 : V5, V6 {};
+
+struct Base4 {};
+struct V7 : virtual Base4 { virtual void f() = 0; };
+struct V8 : virtual Base4 { virtual void g() = 0; };
+struct D5 : V7, V8 {};
+
+struct Base5 { virtual void f() = 0; };
+struct V9 : virtual Base5 { virtual void f(); };
+struct V10 : virtual Base5 { virtual void g() = 0; };
+struct D6 : V9, V10 {};
+
+struct Base6 { virtual void f(); };
+struct Base7 { virtual void g(); };
+struct V15 : virtual Base6 { virtual void f() = 0; };
+struct V16 : virtual Base7 { virtual void g() = 0; };
+// CHECK-MESSAGES: [[@LINE+2]]:1: warning: inheriting multiple classes that aren't pure virtual is discouraged [misc-multiple-inheritance]
+// CHECK-NEXT: struct D9 : V15, V16 {};
+struct D9 : V15, V16 {};
+
+struct Static_Base { static void foo(); };
+struct V11 : virtual Static_Base {};
+struct V12 : virtual Static_Base {};
+struct D7 : V11, V12 {};
+
+struct Static_Base_2 {};
+struct V13 : virtual Static_Base_2 { static void f(); };
+struct V14 : virtual Static_Base_2 { static void g(); };
+struct D8 : V13, V14 {};
+
+template<typename T> struct A : T {};
+template<typename T> struct B : virtual T {};
+
+template<typename> struct C {};
+template<typename T> struct D : C<T> {};
+
+// Check clang_tidy does not crash on this code.
+template <class T>
+struct WithTemplBase : T {
+  WithTemplBase();
+};
+
+void test_no_crash() {
+  auto foo = []() {};
+  WithTemplBase<decltype(foo)>();
+}
+
+struct S1 {};
+struct S2 {};
+
+struct S3 : S1, S2 {};
+
+namespace N {
+
+struct S1 { int i; };
+struct S2 { int i; };
+
+// CHECK-MESSAGES: [[@LINE+1]]:1: warning: inheriting multiple classes that aren't pure virtual is discouraged [misc-multiple-inheritance]
+struct S3 : S1, S2 {};
+
+} // namespace N

@Bhuvan1527 Bhuvan1527 mentioned this pull request Dec 10, 2025
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github-actions bot commented Dec 10, 2025 •
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✅ With the latest revision this PR passed the C/C++ code formatter.

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github-actions bot commented Dec 10, 2025 •
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✅ With the latest revision this PR passed the C/C++ code linter.

EugeneZelenko
EugeneZelenko reviewed Dec 10, 2025
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Documentation was not moved and Release Notes entry is missing.

zeyi2
zeyi2 requested changes Dec 10, 2025
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@Bhuvan1527 Bhuvan1527 force-pushed the move-fucshia-multiInher-misc branch from dddbc62 to 629487c Compare December 10, 2025 07:55
@Bhuvan1527
[clang-tidy] Moved Multiple Inheritence check from fuchsia to misc mo…
88b8b46 
…dule

Resolves: [llvm#171136](llvm#171136)
Referred the issue tagged in the issue mentioned.
@Bhuvan1527 Bhuvan1527 force-pushed the move-fucshia-multiInher-misc branch from 629487c to 88b8b46 Compare December 10, 2025 08:09
@zeyi2 zeyi2 self-requested a review December 10, 2025 10:44
zeyi2
zeyi2 requested changes Dec 11, 2025
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The code change looks nice. However you still need to update the documentations.

more specifically:

  • Edit fuchsia/multiple-inheritance.rst
  • Create a new doc for misc/multiple-inheritance.rst
  • Modify list.rst for correct aliasing
  • Document the change in clang-tools-extra/docs/ReleaseNotes.rst

You can use this PR as a style reference.

@Bhuvan1527
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Bhuvan1527 commented Dec 11, 2025

The code change looks nice. However you still need to update the documentations.

more specifically:

  • Edit fuchsia/multiple-inheritance.rst
  • Create a new doc for misc/multiple-inheritance.rst
  • Modify list.rst for correct aliasing
  • Document the change in clang-tools-extra/docs/ReleaseNotes.rst

You can use this PR as a style reference.

Thank you very much for the detailed file list and reference pr @zeyi2 .

@Bhuvan1527 Bhuvan1527 force-pushed the move-fucshia-multiInher-misc branch 2 times, most recently from ca0c334 to de332d3 Compare December 11, 2025 12:41
EugeneZelenko
EugeneZelenko reviewed Dec 11, 2025
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vbvictor
vbvictor requested changes Dec 11, 2025
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zeyi2
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May be a good idea to add reference here.

@Bhuvan1527 Bhuvan1527 force-pushed the move-fucshia-multiInher-misc branch from de332d3 to afe7713 Compare December 12, 2025 05:48
vbvictor
vbvictor approved these changes Dec 12, 2025
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lgtm with nit

zeyi2
zeyi2 approved these changes Dec 12, 2025
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LGTM, thanks!

Also, you can apply vbvictor's suggestion like this.

@Bhuvan1527
[clang-tidy] Moved Multiple Inheritence check from fuchsia to misc mo…
42a36f0 
…dule

Updated the documentation in the commit,
1. ReleaseNotes.rst
2. respective docs in the docs/clang-tidy/checks/
3. list.rst
@Bhuvan1527 Bhuvan1527 force-pushed the move-fucshia-multiInher-misc branch from afe7713 to 42a36f0 Compare December 12, 2025 11:13
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Bhuvan1527 commented Dec 13, 2025

@zeyi2 , please trigger the pr merge. I don't have permission to merge.

Thank you

@zeyi2 zeyi2 merged commit e0379b8 into llvm:main Dec 13, 2025
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@vbvictor vbvictor vbvictor approved these changes

@zeyi2 zeyi2 zeyi2 approved these changes

@localspook localspook Awaiting requested review from localspook

@EugeneZelenko EugeneZelenko Awaiting requested review from EugeneZelenko

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[clang-tidy] Rename 'fuchsia-multiple-inheritance' check to 'misc' module and keep initial as alias.

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