[clang-tidy] adjust treating of array-of-pointers when 'AnalyzePointers' is deactivated

'misc-const-correctness' previously considered arrays as 'Values' independent of the type of the elements.
This is inconsistent with the configuration of the check to disable treating pointers as values.
This patch rectifies this inconsistency.

Fixes #56749

Reviewed By: njames93

Differential Revision: https://reviews.llvm.org/D130793

Author: JonasToth

clang-tools-extra/clang-tidy/misc/ConstCorrectnessCheck.cpp

@@ -12,8 +12,6 @@
 #include "clang/ASTMatchers/ASTMatchFinder.h"
 #include "clang/ASTMatchers/ASTMatchers.h"
 
-#include <iostream>
-
 using namespace clang::ast_matchers;
 
 namespace clang {
@@ -132,6 +130,12 @@ void ConstCorrectnessCheck::check(const MatchFinder::MatchResult &Result) {
     VC = VariableCategory::Reference;
   if (Variable->getType()->isPointerType())
     VC = VariableCategory::Pointer;
+  if (Variable->getType()->isArrayType()) {
+    if (const auto *ArrayT = dyn_cast<ArrayType>(Variable->getType())) {
+      if (ArrayT->getElementType()->isPointerType())
+        VC = VariableCategory::Pointer;
+    }
+  }
 
   // Each variable can only be in one category: Value, Pointer, Reference.
   // Analysis can be controlled for every category.

clang-tools-extra/test/clang-tidy/checkers/misc/const-correctness-pointer-as-values.cpp

@@ -10,4 +10,65 @@ void potential_const_pointer() {
   double *p_local0 = &np_local0[1];
   // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'double *' can be declared 'const'
   // CHECK-FIXES: double *const p_local0
+
+  using doublePtr = double*;
+  using doubleArray = double[15];
+  doubleArray np_local1;
+  doublePtr p_local1 = &np_local1[0];
+  // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local1' of type 'doublePtr' (aka 'double *') can be declared 'const'
+  // CHECK-FIXES: doublePtr const p_local1
+}
+
+void range_for() {
+  int np_local0[2] = {1, 2};
+  int *p_local0[2] = {&np_local0[0], &np_local0[1]};
+  // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'int *[2]' can be declared 'const'
+  // CHECK-FIXES: int *const p_local0[2]
+  for (const int *p_local1 : p_local0) {
+  // CHECK-MESSAGES: [[@LINE-1]]:8: warning: variable 'p_local1' of type 'const int *' can be declared 'const'
+  // CHECK-FIXES: for (const int *const p_local1 : p_local0)
+  }
+
+  int *p_local2[2] = {nullptr, nullptr};
+  // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local2' of type 'int *[2]' can be declared 'const'
+  // CHECK-FIXES: int *const p_local2[2]
+  for (const auto *con_ptr : p_local2) {
+  }
+
+}
+
+template <typename T>
+struct SmallVectorBase {
+  T data[4];
+  void push_back(const T &el) {}
+  int size() const { return 4; }
+  T *begin() { return data; }
+  const T *begin() const { return data; }
+  T *end() { return data + 4; }
+  const T *end() const { return data + 4; }
+};
+
+template <typename T>
+struct SmallVector : SmallVectorBase<T> {};
+
+template <class T>
+void EmitProtocolMethodList(T &&Methods) {
+  // Note: If the template is uninstantiated the analysis does not figure out,
+  // that p_local0 could be const. Not sure why, but probably bails because
+  // some expressions are type-dependent.
+  SmallVector<const int *> p_local0;
+  // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'SmallVector<const int *>' can be declared 'const'
+  // CHECK-FIXES: SmallVector<const int *> const p_local0
+  SmallVector<const int *> np_local0;
+  for (const auto *I : Methods) {
+    if (I == nullptr)
+      np_local0.push_back(I);
+  }
+  p_local0.size();
+}
+void instantiate() {
+  int *p_local0[4] = {nullptr, nullptr, nullptr, nullptr};
+  // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'int *[4]' can be declared 'const'
+  // CHECK-FIXES: int *const p_local0[4]
+  EmitProtocolMethodList(p_local0);
 }

clang-tools-extra/test/clang-tidy/checkers/misc/const-correctness-values.cpp

@@ -526,18 +526,13 @@ void range_for() {
   // CHECK-FIXES: int const p_local1[2]
   for (const int &const_ref : p_local1) {
   }
+}
 
-  int *p_local2[2] = {&np_local0[0], &np_local0[1]};
-  // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local2' of type 'int *[2]' can be declared 'const'
-  // CHECK-FIXES: int *const p_local2[2]
-  for (const int *con_ptr : p_local2) {
-  }
-
-  int *p_local3[2] = {nullptr, nullptr};
-  // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local3' of type 'int *[2]' can be declared 'const'
-  // CHECK-FIXES: int *const p_local3[2]
-  for (const auto *con_ptr : p_local3) {
-  }
+void arrays_of_pointers_are_ignored() {
+  int *np_local0[2] = {nullptr, nullptr};
+  
+  using intPtr = int*;
+  intPtr np_local1[2] = {nullptr, nullptr};
 }
 
 inline void *operator new(decltype(sizeof(void *)), void *p) { return p; }
@@ -908,41 +903,6 @@ void vlas() {
   sizeof(int[++N]);
 }
 
-template <typename T>
-struct SmallVectorBase {
-  T data[4];
-  void push_back(const T &el) {}
-  int size() const { return 4; }
-  T *begin() { return data; }
-  const T *begin() const { return data; }
-  T *end() { return data + 4; }
-  const T *end() const { return data + 4; }
-};
-
-template <typename T>
-struct SmallVector : SmallVectorBase<T> {};
-
-template <class T>
-void EmitProtocolMethodList(T &&Methods) {
-  // Note: If the template is uninstantiated the analysis does not figure out,
-  // that p_local0 could be const. Not sure why, but probably bails because
-  // some expressions are type-dependent.
-  SmallVector<const int *> p_local0;
-  // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'SmallVector<const int *>' can be declared 'const'
-  // CHECK-FIXES: SmallVector<const int *> const p_local0
-  SmallVector<const int *> np_local0;
-  for (const auto *I : Methods) {
-    if (I == nullptr)
-      np_local0.push_back(I);
-  }
-  p_local0.size();
-}
-void instantiate() {
-  int *p_local0[4] = {nullptr, nullptr, nullptr, nullptr};
-  // CHECK-MESSAGES: [[@LINE-1]]:3: warning: variable 'p_local0' of type 'int *[4]' can be declared 'const'
-  // CHECK-FIXES: int *const p_local0[4]
-  EmitProtocolMethodList(p_local0);
-}
 struct base {
   int member;
 };