Supresses misc-move-constructor-init warning for const fields.

[lethalantidote]

Summary

Supresses misc-move-constructor init warning for const fields.

[alexfh]

clang-tools-extra/test/clang-tidy/misc-move-constructor-init.cpp

88

The test is fine, but it would also pass, if the check verified constness of the field being initialized. I'd suggest adding another one that shows a const-qualified initializer used to initialize a non-const field.

90

Missing semicolon. I wonder how the test still passes. It passes, doesn't it?

[lethalantidote]

• Addresses alexfh's comments.

[alexfh]

LG. I'll commit the patch for you.

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

const auto *Initializer =
       Result.Nodes.getNodeAs<CXXCtorInitializer>("move-init");
 
   // Do not diagnose if the expression used to perform the initialization is a
   // trivially-copyable type.
   QualType QT = Initializer->getInit()->getType();
   if (QT.isTriviallyCopyableType(*Result.Context))
     return;
 
+  if (QT.isConstQualified())
+    return;
+
   const auto *RD = QT->getAsCXXRecordDecl();
   if (RD && RD->isTriviallyCopyable())
     return;
 
   // Diagnose when the class type has a move constructor available, but the
   // ctor-initializer uses the copy constructor instead.
   const CXXConstructorDecl *Candidate = nullptr;
   for (const auto *Ctor : CopyCtor->getParent()->ctors()) {

clang-tools-extra/test/clang-tidy/misc-move-constructor-init.cpp

struct M {
   M(M &&RHS) : Mem(RHS.Mem) {}
 };
 
 struct N {
   B Mem;
   N(N &&RHS) : Mem(move(RHS.Mem)) {}
 };
 
+struct O {
+  O(O&& other) : b(other.b) {} // ok
+  const B b;
+};
+
+struct P {
+  P(O&& other) : b(other.b) {} // ok
+  B b;
+};
+
 struct Movable {
   Movable(Movable &&) = default;
   Movable(const Movable &) = default;
   Movable &operator=(const Movable &) = default;
   ~Movable() {}
 };
 
 struct TriviallyCopyable {