[clang-tools-extra] [clang-tidy] Add new check: `readability-use-concise-preprocessor-directives` (PR #146830)

[Victor Chernyakin via cfe-commits]

================
@@ -0,0 +1,138 @@
+// RUN: %check_clang_tidy -std=c++98 -check-suffixes=,CXX %s readability-use-concise-preprocessor-directives %t
+// RUN: %check_clang_tidy -std=c++11 -check-suffixes=,CXX %s readability-use-concise-preprocessor-directives %t
+// RUN: %check_clang_tidy -std=c++14 -check-suffixes=,CXX %s readability-use-concise-preprocessor-directives %t
+// RUN: %check_clang_tidy -std=c++17 -check-suffixes=,CXX %s readability-use-concise-preprocessor-directives %t
+// RUN: %check_clang_tidy -std=c++20 -check-suffixes=,CXX %s readability-use-concise-preprocessor-directives %t
+// RUN: %check_clang_tidy -std=c++23-or-later -check-suffixes=,23,CXX,CXX23 %s readability-use-concise-preprocessor-directives %t
+
+// RUN: %check_clang_tidy -std=c99 %s readability-use-concise-preprocessor-directives %t -- -- -x c
+// RUN: %check_clang_tidy -std=c11 %s readability-use-concise-preprocessor-directives %t -- -- -x c
+// RUN: %check_clang_tidy -std=c23-or-later -check-suffixes=,23 %s readability-use-concise-preprocessor-directives %t -- -- -x c
+
+// CHECK-MESSAGES: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely using #ifdef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES: #ifdef FOO
+#if defined(FOO)
+// CHECK-MESSAGES-23: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely using #elifdef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES-23: #elifdef BAR
+#elif defined(BAR)
+#endif
+
+// CHECK-MESSAGES: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely using #ifdef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES: #ifdef FOO
+#if defined FOO
+// CHECK-MESSAGES-23: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely using #elifdef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES-23: #elifdef BAR
+#elif defined BAR
+#endif
+
+// CHECK-MESSAGES: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely using #ifdef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES: #ifdef FOO
+#if (defined(FOO))
+// CHECK-MESSAGES-23: :[[@LINE+2]]:4: warning: preprocessor condition can be written more concisely using #elifdef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES-23: #  elifdef BAR
+#  elif (defined(BAR))
+#endif
+
+// CHECK-MESSAGES: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely using #ifdef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES: #ifdef FOO
+#if (defined FOO)
+// CHECK-MESSAGES-23: :[[@LINE+2]]:4: warning: preprocessor condition can be written more concisely using #elifdef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES-23: #  elifdef BAR
+#  elif (defined BAR)
+#endif
+
+// CHECK-MESSAGES: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely using #ifndef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES: #ifndef FOO
+#if !defined(FOO)
+// CHECK-MESSAGES-23: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely using #elifndef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES-23: #elifndef BAR
+#elif !defined(BAR)
+#endif
+
+#ifdef __cplusplus
+// CHECK-MESSAGES-CXX: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely using #ifndef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES-CXX: #ifndef FOO
+#if not defined(FOO)
+// CHECK-MESSAGES-CXX23: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely using #elifndef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES-CXX23: #elifndef BAR
+#elif not defined(BAR)
+#endif
+#endif // __cplusplus
+
+// CHECK-MESSAGES: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely using #ifndef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES: #ifndef FOO
+#if !defined FOO
+// CHECK-MESSAGES-23: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely using #elifndef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES-23: #elifndef BAR
+#elif !defined BAR
+#endif
+
+#ifdef __cplusplus
+// CHECK-MESSAGES-CXX: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely using #ifndef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES-CXX: #ifndef FOO
+#if not defined FOO
+// CHECK-MESSAGES-CXX23: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely using #elifndef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES-CXX23: #elifndef BAR
+#elif not defined BAR
+#endif
+#endif // __cplusplus
+
+// CHECK-MESSAGES: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely using #ifndef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES: #ifndef FOO
+#if (!defined(FOO))
+// CHECK-MESSAGES-23: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely using #elifndef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES-23: #elifndef BAR
+#elif (!defined(BAR))
+#endif
+
+// CHECK-MESSAGES: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely using #ifndef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES: #ifndef FOO
+#if (!defined FOO)
+// CHECK-MESSAGES-23: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely using #elifndef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES-23: #elifndef BAR
+#elif (!defined BAR)
+#endif
+
+// CHECK-MESSAGES: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely using #ifndef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES: #ifndef FOO
+#if !(defined(FOO))
+// CHECK-MESSAGES-23: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely using #elifndef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES-23: #elifndef BAR
+#elif !(defined(BAR))
+#endif
+
+// CHECK-MESSAGES: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely using #ifndef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES: #ifndef FOO
+#if !(defined FOO)
+// CHECK-MESSAGES-23: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely using #elifndef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES-23: #elifndef BAR
+#elif !(defined BAR)
+#endif
+
+// These cases with many parentheses and negations are unrealistic, but
+// handling them doesn't really add any complexity to the implementation.
+// Test them for good measure.
+
+// CHECK-MESSAGES: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely using #ifndef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES: #ifndef FOO
+#if !((!!(defined(FOO))))
+// CHECK-MESSAGES-23: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely using #elifdef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES-23: #elifdef BAR
+#elif ((!(!(defined(BAR)))))
+#endif
+
+// CHECK-MESSAGES: :[[@LINE+2]]:2: warning: preprocessor condition can be written more concisely using #ifndef [readability-use-concise-preprocessor-directives]
+// CHECK-FIXES: #ifndef FOO
+#if !((!!(defined FOO)))
----------------
localspook wrote:

2, the first example in 3, and 4 are not valid syntax. I've added tests for the others.

https://github.com/llvm/llvm-project/pull/146830