[clang-tools-extra] [clang-tidy] Add `modernize-use-uniform-initializer` check (PR #91124)

[Piotr Zegar via cfe-commits]

================
@@ -0,0 +1,174 @@
+// RUN: %check_clang_tidy -std=c++11 %s modernize-use-uniform-initializer %t
+
+int cinit_0 = 0;
+// CHECK-MESSAGES: :[[@LINE-1]]:13: warning: Use uniform initializer instead of C-style initializer [modernize-use-uniform-initializer]
+// CHECK-FIXES: int cinit_0 {0};
+
+int cinit_1=0;
+// CHECK-MESSAGES: :[[@LINE-1]]:12: warning: Use uniform initializer instead of C-style initializer [modernize-use-uniform-initializer]
+// CHECK-FIXES: int cinit_1{0};
+
+int callinit_0(0);
+// CHECK-MESSAGES: :[[@LINE-1]]:15: warning: Use uniform initializer instead of call-style initializer [modernize-use-uniform-initializer]
+// CHECK-FIXES: int callinit_0{0};
+
+int callinit_1 ( 0 );
+// CHECK-MESSAGES: :[[@LINE-1]]:16: warning: Use uniform initializer instead of call-style initializer [modernize-use-uniform-initializer]
+// CHECK-FIXES: int callinit_1 {0};
+
+int callinit_2 ( ((3 + 1 + 4) + 1 + 5) );
+// CHECK-MESSAGES: :[[@LINE-1]]:16: warning: Use uniform initializer instead of call-style initializer [modernize-use-uniform-initializer]
+// CHECK-FIXES: int callinit_2 {((3 + 1 + 4) + 1 + 5)};
+
+int callinit_3((9-2)+(6+5));
+// CHECK-MESSAGES: :[[@LINE-1]]:15: warning: Use uniform initializer instead of call-style initializer [modernize-use-uniform-initializer]
+// CHECK-FIXES: int callinit_3{(9-2)+(6+5)};
+
+int callinit_4 ((3 * 5 + (8 - 9) ));
+// CHECK-MESSAGES: :[[@LINE-1]]:16: warning: Use uniform initializer instead of call-style initializer [modernize-use-uniform-initializer]
+// CHECK-FIXES: int callinit_4 {(3 * 5 + (8 - 9) )};
+
+int callinit_5((7 + (-9)));
+// CHECK-MESSAGES: :[[@LINE-1]]:15: warning: Use uniform initializer instead of call-style initializer [modernize-use-uniform-initializer]
+// CHECK-FIXES: int callinit_5{(7 + (-9))};
+
+int mixed_0 = {0};
+// CHECK-MESSAGES: :[[@LINE-1]]:13: warning: Use uniform initializer instead of C-style initializer [modernize-use-uniform-initializer]
+// CHECK-FIXES: int mixed_0 {0};
+
+int mixed_1={0};
+// CHECK-MESSAGES: :[[@LINE-1]]:12: warning: Use uniform initializer instead of C-style initializer [modernize-use-uniform-initializer]
+// CHECK-FIXES: int mixed_1{0};
+
+int noinit;
+
+int correct_0{0};
+
+int correct_1 {0};
+
+struct CInitList_0 {
+    CInitList_0() : x(0) {}
+    // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: Use uniform initializer instead of C-style initializer [modernize-use-uniform-initializer]
+    // CHECK-FIXES: CInitList_0() : x{0} {}
+
+    int x;
+};
+
+struct CInitList_1 {
+    CInitList_1():x(0) {}
+    // CHECK-MESSAGES: :[[@LINE-1]]:20: warning: Use uniform initializer instead of C-style initializer [modernize-use-uniform-initializer]
+    // CHECK-FIXES: CInitList_1():x{0} {}
+
+    int x;
+};
+
+struct CInitList_2 {
+    CInitList_2() : x ( 0 ) {}
+    // CHECK-MESSAGES: :[[@LINE-1]]:23: warning: Use uniform initializer instead of C-style initializer [modernize-use-uniform-initializer]
+    // CHECK-FIXES: CInitList_2() : x {0} {}
+
+    int x;
+};
+
+struct Correct_0 {
+    Correct_0() : x{0} {}
+
+    int x;
+};
+
+struct Correct_1 {
+    Correct_1():x{0} {}
+
+    int x;
+};
+
+struct InClassInitializers {
+    int cinit_0 = 0;
+    // CHECK-MESSAGES: :[[@LINE-1]]:17: warning: Use uniform initializer instead of C-style initializer [modernize-use-uniform-initializer]
+    // CHECK-FIXES: int cinit_0 {0};
+
+    int cinit_1=0;
+    // CHECK-MESSAGES: :[[@LINE-1]]:16: warning: Use uniform initializer instead of C-style initializer [modernize-use-uniform-initializer]
+    // CHECK-FIXES: int cinit_1{0};
+
+    int mixed_0 = {0};
+    // CHECK-MESSAGES: :[[@LINE-1]]:17: warning: Use uniform initializer instead of C-style initializer [modernize-use-uniform-initializer]
+    // CHECK-FIXES: int mixed_0 {0};
+
+    int mixed_1={0};
+    // CHECK-MESSAGES: :[[@LINE-1]]:16: warning: Use uniform initializer instead of C-style initializer [modernize-use-uniform-initializer]
+    // CHECK-FIXES: int mixed_1{0};
+
+    int noinit;
+
+    int correct_0 {0};
+
+    int correct_1{0};
+};
+
+// Defaulted function arguments cannot use the uniform initializer
+void f(int x = 0) {}
+
+struct A {
+    A() = default;
+    A(int) {}
+    A(int, int) {}
+};
+
+A a_0;
+A a_1{};
+A a_2(); // This is not a variable declaration it is actually a function definition (most vexing parse)
+A a_3{21};
+A a_4{ 21 };
+A a_5(42);
+// CHECK-MESSAGES: :[[@LINE-1]]:6: warning: Use uniform initializer instead of call-style initializer [modernize-use-uniform-initializer]
+// CHECK-FIXES: A a_5{42};
+A a_6 ( 42 );
+// CHECK-MESSAGES: :[[@LINE-1]]:7: warning: Use uniform initializer instead of call-style initializer [modernize-use-uniform-initializer]
+// CHECK-FIXES: A a_6 {42};
+A a_7{0, 1};
+A a_8{ 0, 1 };
+A a_9(0, 1);
+// CHECK-MESSAGES: :[[@LINE-1]]:6: warning: Use uniform initializer instead of call-style initializer [modernize-use-uniform-initializer]
+// CHECK-FIXES: A a_9{0, 1};
+A a_10( 1, 0 );
+// CHECK-MESSAGES: :[[@LINE-1]]:7: warning: Use uniform initializer instead of call-style initializer [modernize-use-uniform-initializer]
+// CHECK-FIXES: A a_10{1, 0};
+A a_11(A(3));
+// CHECK-MESSAGES: :[[@LINE-1]]:7: warning: Use uniform initializer instead of call-style initializer [modernize-use-uniform-initializer]
+// CHECK-FIXES: A a_11{A(3)};
+A a_12 ( A(3) );
+// CHECK-MESSAGES: :[[@LINE-1]]:8: warning: Use uniform initializer instead of call-style initializer [modernize-use-uniform-initializer]
+// CHECK-FIXES: A a_12 {A(3)};
+
+struct Delegating {
+    Delegating() : Delegating(0) {}
+    // CHECK-MESSAGES: :[[@LINE-1]]:30: warning: Use uniform initializer instead of C-style initializer [modernize-use-uniform-initializer]
+    // CHECK-FIXES: Delegating() : Delegating{0} {}
+
+    Delegating(int) {}
+};
+
+int narrow_0 = 3.14;
+// CHECK-MESSAGES: :[[@LINE-1]]:14: warning: Use uniform initializer instead of C-style initializer [modernize-use-uniform-initializer]
+// CHECK-FIXES: int narrow_0 {static_cast<int>(3.14)};
+int narrow_1=37.73;
+// CHECK-MESSAGES: :[[@LINE-1]]:13: warning: Use uniform initializer instead of C-style initializer [modernize-use-uniform-initializer]
+// CHECK-FIXES: int narrow_1{static_cast<int>(37.73)};
----------------
PiotrZSL wrote:

from one point of view its fine, from other it's hidding narrowing conversion, maybe generate those fixes, but attach them to notes instead of to main diagnostic, and put entry in documentation, and in note print warning about narrowing conversion

https://github.com/llvm/llvm-project/pull/91124