[clang-tidy] Add check readability-implicit-bool-cast

Summary:
This is another check that I ported to clang-tidy from colobot-lint tool.

As previously discussed on cfe-dev mailing list, this is one of those
checks that I think is general and useful enough for contribution to
clang-tidy.

This patch contains implementation of check taken from colobot-lint, but
it is extended a great deal, including FixIt hints for automated
refactoring, exhaustive testcases, and user documentation.

Reviewers: sbenza, aaron.ballman, alexfh

Subscribers: Eugene.Zelenko

Differential Revision: http://reviews.llvm.org/D13635

llvm-svn: 251235

1 files changed, 42 insertions, 0 deletions

diff --git a/clang-tools-extra/test/clang-tidy/readability-implicit-bool-cast-cxx98.cpp b/clang-tools-extra/test/clang-tidy/readability-implicit-bool-cast-cxx98.cpp
new file mode 100644
index 00000000000..1cd5c87d335
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/readability-implicit-bool-cast-cxx98.cpp
@@ -0,0 +1,42 @@
+// RUN: clang-tidy %s -checks=-*,readability-implicit-bool-cast -- -std=c++98
+
+#include <cstddef> // for NULL
+
+template<typename T>
+void functionTaking(T);
+
+struct Struct {
+  int member;
+};
+
+void useOldNullMacroInReplacements() {
+  int* pointer = NULL;
+  functionTaking<bool>(pointer);
+  // CHECK-MESSAGES: :[[@LINE-1]]:24: warning: implicit cast 'int *' -> bool [readability-implicit-bool-cast]
+  // CHECK-FIXES: functionTaking<bool>(pointer != 0);
+
+  int Struct::* memberPointer = NULL;
+  functionTaking<bool>(!memberPointer);
+  // CHECK-MESSAGES: :[[@LINE-1]]:25: warning: implicit cast 'int struct Struct::*' -> bool
+  // CHECK-FIXES: functionTaking<bool>(memberPointer == 0);
+}
+
+void fixFalseLiteralConvertingToNullPointer() {
+  functionTaking<int*>(false);
+  // CHECK-MESSAGES: :[[@LINE-1]]:24: warning: implicit cast bool -> 'int *'
+  // CHECK-FIXES: functionTaking<int*>(0);
+
+  int* pointer = NULL;
+  if (pointer == false) {}
+  // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: implicit cast bool -> 'int *'
+  // CHECK-FIXES: if (pointer == 0) {}
+
+  functionTaking<int Struct::*>(false);
+  // CHECK-MESSAGES: :[[@LINE-1]]:33: warning: implicit cast bool -> 'int struct Struct::*'
+  // CHECK-FIXES: functionTaking<int Struct::*>(0);
+
+  int Struct::* memberPointer = NULL;
+  if (memberPointer != false) {}
+  // CHECK-MESSAGES: :[[@LINE-1]]:24: warning: implicit cast bool -> 'int struct Struct::*'
+  // CHECK-FIXES: if (memberPointer != 0) {}
+}