[clang-tools-extra] r248418 - Fix loop-convert for const references to containers.

[Manuel Klimek via cfe-commits]

Author: klimek
Date: Wed Sep 23 13:40:47 2015
New Revision: 248418

URL: http://llvm.org/viewvc/llvm-project?rev=248418&view=rev
Log:
Fix loop-convert for const references to containers.

Previously we would use a non-const loop variable in the range-based
loop for:
void f(const std::vector<int> &v) {
  for (size_t i = 0; i < v.size(); ++i) {
Now we use const auto&.

Note that we'll also want to use a copy at least for simple types.

Modified:
    clang-tools-extra/trunk/clang-tidy/modernize/LoopConvertCheck.cpp
    clang-tools-extra/trunk/test/clang-tidy/modernize-loop-convert-basic.cpp

Modified: clang-tools-extra/trunk/clang-tidy/modernize/LoopConvertCheck.cpp
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/clang-tidy/modernize/LoopConvertCheck.cpp?rev=248418&r1=248417&r2=248418&view=diff
==============================================================================
--- clang-tools-extra/trunk/clang-tidy/modernize/LoopConvertCheck.cpp (original)
+++ clang-tools-extra/trunk/clang-tidy/modernize/LoopConvertCheck.cpp Wed Sep 23 13:40:47 2015
@@ -391,6 +391,12 @@ static bool containerIsConst(const Expr
         return false;
       CType = CType->getPointeeType();
     }
+    // If VDec is a reference to a container, Dereference is false,
+    // but we still need to check the const-ness of the underlying container
+    // type.
+    if (const auto &RT = CType->getAs<ReferenceType>()) {
+      CType = RT->getPointeeType();
+    }
     return CType.isConstQualified();
   }
   return false;

Modified: clang-tools-extra/trunk/test/clang-tidy/modernize-loop-convert-basic.cpp
URL: http://llvm.org/viewvc/llvm-project/clang-tools-extra/trunk/test/clang-tidy/modernize-loop-convert-basic.cpp?rev=248418&r1=248417&r2=248418&view=diff
==============================================================================
--- clang-tools-extra/trunk/test/clang-tidy/modernize-loop-convert-basic.cpp (original)
+++ clang-tools-extra/trunk/test/clang-tidy/modernize-loop-convert-basic.cpp Wed Sep 23 13:40:47 2015
@@ -544,6 +544,18 @@ void constness() {
   // CHECK-FIXES-NEXT: sum += elem + 2;
 }
 
+void ConstRef(const dependent<int>& ConstVRef) {
+  int sum = 0;
+  // FIXME: This does not work with size_t (probably due to the implementation
+  // of dependent); make dependent work exactly like a std container type.
+  for (int i = 0; i < ConstVRef.size(); ++i) {
+    sum += ConstVRef[i];
+  }
+  // CHECK-MESSAGES: :[[@LINE-3]]:3: warning: use range-based for loop instead
+  // CHECK-FIXES: for (const auto & elem : ConstVRef)
+  // CHECK-FIXES-NEXT: sum += elem;
+}
+
 // Check for loops that don't mention containers.
 void noContainer() {
   for (auto i = 0; i < v.size(); ++i) {