[clang-tidy] Ignore implicit casts in modernize-use-default-member-init

[malcolm.parsons]

Summary

Initialising a pointer from nullptr involves an implicit cast.
Ignore it after getting initialiser from InitListExpr.

Fixes: PR44440

[JonasToth]

LGTM in general. The linked bug report misses a "4" --> PR44440, so please the description for that.

clang-tools-extra/test/clang-tidy/checkers/modernize-use-default-member-init.cpp

294

are those related to this patch?

[malcolm.parsons]

clang-tools-extra/test/clang-tidy/checkers/modernize-use-default-member-init.cpp

294

Yes - checking that this style of initialisation works in all cases.

[JonasToth]

K. Thank you for fixing it!

[hans]

It seems that while this commit got pushed to GitHub, it's not actually part of master or any other branches.

[malcolm.parsons]

In D72630#1823525, @hans wrote:

It seems that while this commit got pushed to GitHub, it's not actually part of master or any other branches.

This was my first push to llvm's GitHub repository, so I may have done something wrong.

The changeset looks like it's in master to me:

$ git branch -r --contains 45924eb
  origin/HEAD -> origin/master
  origin/master
  origin/release/10.x

[hans]

Ah, you're right, it's there.

The reason for my comment was http://lists.llvm.org/pipermail/llvm-branch-commits/2020-January/013555.html but it seems it was also successfully pushed to master. Sorry for the noise.

clang-tools-extra/clang-tidy/modernize/UseDefaultMemberInitCheck.cpp

static const Expr *ignoreUnaryPlus(const Expr *E) {
   if (UnaryOp && UnaryOp->getOpcode() == UO_Plus)
     return UnaryOp->getSubExpr();
   return E;
 }
 
 static const Expr *getInitializer(const Expr *E) {
   auto *InitList = dyn_cast<InitListExpr>(E);
   if (InitList && InitList->getNumInits() == 1)
-    return InitList->getInit(0);
+    return InitList->getInit(0)->IgnoreParenImpCasts();
   return E;
 }
 
 static bool sameValue(const Expr *E1, const Expr *E2) {
   E1 = ignoreUnaryPlus(getInitializer(E1->IgnoreParenImpCasts()));
   E2 = ignoreUnaryPlus(getInitializer(E2->IgnoreParenImpCasts()));
 
   if (isZero(E1) && isZero(E2))

clang-tools-extra/test/clang-tidy/checkers/modernize-use-default-member-init.cpp

struct ExistingInt {
   // CHECK-MESSAGES: :[[@LINE-3]]:58: warning: member initializer for 'e6' is redundant
   // CHECK-FIXES: ExistingInt(long) : e1(5), e2(5),  e5(5) {}
   ExistingInt(char) : e1(-5), e2(-5), e3(-5), e4(-5), e5(-5), e6(-5) {}
   // CHECK-MESSAGES: :[[@LINE-1]]:55: warning: member initializer for 'e5' is redundant
   // CHECK-FIXES: ExistingInt(char) : e1(-5), e2(-5), e3(-5), e4(-5),  e6(-5) {}
   int e1{};
   int e2 = 0;
   int e3 = {5};
-  int e4 = 5;
+  int e4{5};
   int e5 = -5;
   int e6 = +5;
 };
 
 struct ExistingDouble {
   ExistingDouble(short) : e1(), e2(), e3(), e4(), e5() {}
   // CHECK-MESSAGES: :[[@LINE-1]]:27: warning: member initializer for 'e1' is redundant
   // CHECK-MESSAGES: :[[@LINE-2]]:33: warning: member initializer for 'e2' is redundant
   // CHECK-FIXES: ExistingDouble(short) :  e3(), e4(), e5() {}
   ExistingDouble(int) : e1(0.0), e2(0.0), e3(0.0), e4(0.0), e5(0.0) {}
   // CHECK-MESSAGES: :[[@LINE-1]]:25: warning: member initializer for 'e1' is redundant
   // CHECK-MESSAGES: :[[@LINE-2]]:34: warning: member initializer for 'e2' is redundant
   // CHECK-FIXES: ExistingDouble(int) :  e3(0.0), e4(0.0), e5(0.0) {}
   ExistingDouble(long) : e1(5.0), e2(5.0), e3(5.0), e4(5.0), e5(5.0) {}
   // CHECK-MESSAGES: :[[@LINE-1]]:44: warning: member initializer for 'e3' is redundant
   // CHECK-MESSAGES: :[[@LINE-2]]:62: warning: member initializer for 'e5' is redundant
   // CHECK-FIXES: ExistingDouble(long) : e1(5.0), e2(5.0),  e4(5.0) {}
   ExistingDouble(char) : e1(-5.0), e2(-5.0), e3(-5.0), e4(-5.0), e5(-5.0) {}
   // CHECK-MESSAGES: :[[@LINE-1]]:56: warning: member initializer for 'e4' is redundant
   // CHECK-FIXES: ExistingDouble(char) : e1(-5.0), e2(-5.0), e3(-5.0),  e5(-5.0) {}
   double e1{};
   double e2 = 0.0;
   double e3 = 5.0;
-  double e4 = -5.0;
+  double e4{-5.0};
   double e5 = +5.0;
 };
 
 struct ExistingBool {
   ExistingBool(short) : e1(), e2(), e3() {}
   // CHECK-MESSAGES: :[[@LINE-1]]:25: warning: member initializer for 'e1' is redundant
   // CHECK-MESSAGES: :[[@LINE-2]]:31: warning: member initializer for 'e2' is redundant
   // CHECK-FIXES: ExistingBool(short) :  e3() {}
   ExistingBool(int) : e1(false), e2(false), e3(false) {}
   // CHECK-MESSAGES: :[[@LINE-1]]:23: warning: member initializer for 'e1' is redundant
   // CHECK-MESSAGES: :[[@LINE-2]]:34: warning: member initializer for 'e2' is redundant
   // CHECK-FIXES: ExistingBool(int) :  e3(false) {}
   ExistingBool(long) : e1(true), e2(true), e3(true) {}
   // CHECK-MESSAGES: :[[@LINE-1]]:44: warning: member initializer for 'e3' is redundant
   // CHECK-FIXES: ExistingBool(long) : e1(true), e2(true) {}
   bool e1{};
   bool e2 = false;
-  bool e3 = true;
+  bool e3{true};
 };
 
 struct ExistingEnum {
   ExistingEnum(short) : e1(Foo), e2(Foo) {}
   // CHECK-MESSAGES: :[[@LINE-1]]:25: warning: member initializer for 'e1' is redundant
   // CHECK-FIXES: ExistingEnum(short) :  e2(Foo) {}
   ExistingEnum(int) : e1(Bar), e2(Bar) {}
   // CHECK-MESSAGES: :[[@LINE-1]]:32: warning: member initializer for 'e2' is redundant
struct ExistingPointer {
   // CHECK-FIXES: ExistingPointer(int) :  e4(&e1) {}
   ExistingPointer(long) : e1(nullptr), e2(nullptr), e3(nullptr), e4(&e2) {}
   // CHECK-MESSAGES: :[[@LINE-1]]:27: warning: member initializer for 'e1' is redundant
   // CHECK-MESSAGES: :[[@LINE-2]]:40: warning: member initializer for 'e2' is redundant
   // CHECK-MESSAGES: :[[@LINE-3]]:53: warning: member initializer for 'e3' is redundant
   // CHECK-FIXES: ExistingPointer(long) :  e4(&e2) {}
   int *e1{};
   int *e2 = 0;
-  int *e3 = nullptr;
+  int *e3{nullptr};
   int **e4 = &e1;
 };
 
 struct ExistingString {
   ExistingString(short) : e1(), e2(), e3(), e4() {}
   // CHECK-MESSAGES: :[[@LINE-1]]:27: warning: member initializer for 'e1' is redundant [modernize-use-default-member-init]
   // CHECK-MESSAGES: :[[@LINE-2]]:33: warning: member initializer for 'e2' is redundant
   // CHECK-FIXES: ExistingString(short) :  e3(), e4() {}