[clang-tidy] Support initializer_list in google-explicit-constructor check

Summary:
According to the Google C++ Style Guide, constructors taking a single
std::initializer_list<> should not be marked explicit.

This change also changes the messages according to conventions used in Clang
diagnostics: no capitalization of the first letter, no trailing dot.

Reviewers: djasper

Reviewed By: djasper

Subscribers: curdeius, cfe-commits

Differential Revision: http://reviews.llvm.org/D6427

llvm-svn: 222878

1 files changed, 59 insertions, 0 deletions

diff --git a/clang-tools-extra/test/clang-tidy/google-explicit-constructor.cpp b/clang-tools-extra/test/clang-tidy/google-explicit-constructor.cpp
new file mode 100644
index 00000000000..7866df61720
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/google-explicit-constructor.cpp
@@ -0,0 +1,59 @@
+// RUN: $(dirname %s)/check_clang_tidy.sh %s google-explicit-constructor %t
+// REQUIRES: shell
+
+namespace std {
+  typedef decltype(sizeof(int)) size_t;
+
+  // libc++'s implementation
+  template <class _E>
+  class initializer_list
+  {
+    const _E* __begin_;
+    size_t    __size_;
+
+    initializer_list(const _E* __b, size_t __s)
+      : __begin_(__b),
+        __size_(__s)
+    {}
+
+  public:
+    typedef _E        value_type;
+    typedef const _E& reference;
+    typedef const _E& const_reference;
+    typedef size_t    size_type;
+
+    typedef const _E* iterator;
+    typedef const _E* const_iterator;
+
+    initializer_list() : __begin_(nullptr), __size_(0) {}
+
+    size_t    size()  const {return __size_;}
+    const _E* begin() const {return __begin_;}
+    const _E* end()   const {return __begin_ + __size_;}
+  };
+}
+
+struct A {
+  A() {}
+  A(int x, int y) {}
+  A(std::initializer_list<int> list1) {}
+
+  explicit A(void *x) {}
+  explicit A(void *x, void *y) {}
+
+  explicit A(const A& a) {}
+  // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: copy constructor should not be declared explicit [google-explicit-constructor]
+  // CHECK-FIXES: {{^  }}A(const A& a) {}
+
+  explicit A(std::initializer_list<double> list2) {}
+  // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: initializer-list constructor should not be declared explicit [google-explicit-constructor]
+  // CHECK-FIXES: {{^  }}A(std::initializer_list<double> list2) {}
+
+  A(int x1) {}
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: single-argument constructors must be explicit [google-explicit-constructor]
+  // CHECK-FIXES: {{^  }}explicit A(int x1) {}
+
+  A(double x2, double y = 3.14) {}
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: single-argument constructors must be explicit
+  // CHECK-FIXES: {{^  }}explicit A(double x2, double y = 3.14) {}
+};