Allow the alias to be of a different type.

Summary: Consider a declaration an alias even if it doesn't have the same unqualified type than the container element, as long as one can be converted to the other using only implicit casts.

Reviewers: klimek

Subscribers: alexfh, cfe-commits

Differential Revision: http://reviews.llvm.org/D14442

llvm-svn: 252315

2 files changed, 38 insertions, 13 deletions

diff --git a/clang-tools-extra/clang-tidy/modernize/LoopConvertUtils.cpp b/clang-tools-extra/clang-tidy/modernize/LoopConvertUtils.cpp
index 97e2f7e2191..c50e9238170 100644
--- a/clang-tools-extra/clang-tidy/modernize/LoopConvertUtils.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/LoopConvertUtils.cpp
@@ -342,21 +342,27 @@ static bool isAliasDecl(ASTContext *Context, const Decl *TheDecl,
   if (!VDecl->hasInit())
     return false;
 
-  const Expr *Init =
-      digThroughConstructors(VDecl->getInit()->IgnoreParenImpCasts());
+  bool OnlyCasts = true;
+  const Expr *Init = VDecl->getInit()->IgnoreParenImpCasts();
+  if (Init && isa<CXXConstructExpr>(Init)) {
+    Init = digThroughConstructors(Init);
+    OnlyCasts = false;
+  }
   if (!Init)
     return false;
 
   // Check that the declared type is the same as (or a reference to) the
   // container type.
-  QualType InitType = Init->getType();
-  QualType DeclarationType = VDecl->getType();
-  if (!DeclarationType.isNull() && DeclarationType->isReferenceType())
-    DeclarationType = DeclarationType.getNonReferenceType();
-
-  if (InitType.isNull() || DeclarationType.isNull() ||
-      !Context->hasSameUnqualifiedType(DeclarationType, InitType))
-    return false;
+  if (!OnlyCasts) {
+    QualType InitType = Init->getType();
+    QualType DeclarationType = VDecl->getType();
+    if (!DeclarationType.isNull() && DeclarationType->isReferenceType())
+      DeclarationType = DeclarationType.getNonReferenceType();
+
+    if (InitType.isNull() || DeclarationType.isNull() ||
+        !Context->hasSameUnqualifiedType(DeclarationType, InitType))
+      return false;
+  }
 
   switch (Init->getStmtClass()) {
   case Stmt::ArraySubscriptExprClass: {
@@ -384,8 +390,8 @@ static bool isAliasDecl(ASTContext *Context, const Decl *TheDecl,
     const auto *MemCall = cast<CXXMemberCallExpr>(Init);
     // This check is needed because getMethodDecl can return nullptr if the
     // callee is a member function pointer.
-    if (MemCall->getMethodDecl() &&
-        MemCall->getMethodDecl()->getName() == "at") {
+    const auto *MDecl = MemCall->getMethodDecl();
+    if (MDecl && !isa<CXXConversionDecl>(MDecl) && MDecl->getName() == "at") {
       assert(MemCall->getNumArgs() == 1);
       return isIndexInSubscriptExpr(MemCall->getArg(0), IndexVar);
     }
diff --git a/clang-tools-extra/test/clang-tidy/modernize-loop-convert-extra.cpp b/clang-tools-extra/test/clang-tidy/modernize-loop-convert-extra.cpp
index 2d4d73e0ff8..42796f22710 100644
--- a/clang-tools-extra/test/clang-tidy/modernize-loop-convert-extra.cpp
+++ b/clang-tools-extra/test/clang-tidy/modernize-loop-convert-extra.cpp
@@ -159,7 +159,7 @@ void aliasing() {
   // CHECK-FIXES: for (int Alias : IntArr)
   // CHECK-FIXES-NEXT: for (unsigned J = 0; Alias; ++J)
 
-  struct IntRef { IntRef(const int& i); };
+  struct IntRef { IntRef(); IntRef(const int& i); operator int*(); };
   for (int I = 0; I < N; ++I) {
     IntRef Int(IntArr[I]);
   }
@@ -167,6 +167,25 @@ void aliasing() {
   // CHECK-FIXES: for (int I : IntArr)
   // CHECK-FIXES-NEXT: IntRef Int(I);
 
+  int *PtrArr[N];
+  for (unsigned I = 0; I < N; ++I) {
+    const int* const P = PtrArr[I];
+    printf("%d\n", *P);
+  }
+  // CHECK-MESSAGES: :[[@LINE-4]]:3: warning: use range-based for loop instead
+  // CHECK-FIXES: for (auto P : PtrArr)
+  // CHECK-FIXES-NEXT: printf("%d\n", *P);
+
+  IntRef Refs[N];
+  for (unsigned I = 0; I < N; ++I) {
+    int *P = Refs[I];
+    printf("%d\n", *P);
+  }
+  // CHECK-MESSAGES: :[[@LINE-4]]:3: warning: use range-based for loop instead
+  // CHECK-FIXES: for (auto & Ref : Refs)
+  // CHECK-FIXES-NEXT: int *P = Ref;
+  // CHECK-FIXES-NEXT: printf("%d\n", *P);
+
   // Ensure that removing the alias doesn't leave empty lines behind.
   for (int I = 0; I < N; ++I) {
     auto &X = IntArr[I];