[PATCH] [clang-tidy] Fix for Bug 23161

[Szabolcs Sipos]

The result type of the cast (in the definition of NULL) is restricted to T*.
Also replaced hasDescendant() with has().


http://reviews.llvm.org/D8920

Files:
  clang-tidy/misc/StaticAssertCheck.cpp
  test/clang-tidy/misc-static-assert.cpp

Index: clang-tidy/misc/StaticAssertCheck.cpp
===================================================================
--- clang-tidy/misc/StaticAssertCheck.cpp
+++ clang-tidy/misc/StaticAssertCheck.cpp
@@ -27,15 +27,17 @@
     : ClangTidyCheck(Name, Context) {}
 
 void StaticAssertCheck::registerMatchers(MatchFinder *Finder) {
-  auto IsAlwaysFalse = ignoringParenImpCasts(
-      anyOf(boolLiteral(equals(false)).bind("isAlwaysFalse"),
-            integerLiteral(equals(0)).bind("isAlwaysFalse")));
+  auto IsAlwaysFalse = expr(ignoringParenImpCasts(
+      expr(anyOf(boolLiteral(equals(false)), integerLiteral(equals(0)),
+          nullPtrLiteralExpr())).bind("isAlwaysFalse")));
+  auto IsAlwaysFalseWithCast = ignoringParenImpCasts(anyOf(IsAlwaysFalse,
+      cStyleCastExpr(has(IsAlwaysFalse)).bind("castExpr")));
   auto AssertExprRoot = anyOf(
       binaryOperator(
-          hasOperatorName("&&"),
+          anyOf(hasOperatorName("&&"), hasOperatorName("==")),
           hasEitherOperand(ignoringImpCasts(stringLiteral().bind("assertMSG"))),
-          anyOf(binaryOperator(hasEitherOperand(IsAlwaysFalse)), anything()))
-          .bind("assertExprRoot"),
+          anyOf(binaryOperator(hasEitherOperand(IsAlwaysFalseWithCast)),
+          anything())).bind("assertExprRoot"),
       IsAlwaysFalse);
   auto Condition = expr(anyOf(
       expr(ignoringParenCasts(anyOf(
@@ -60,6 +62,7 @@
   const auto *AssertMSG = Result.Nodes.getNodeAs<StringLiteral>("assertMSG");
   const auto *AssertExprRoot =
       Result.Nodes.getNodeAs<BinaryOperator>("assertExprRoot");
+  const auto *CastExpr = Result.Nodes.getNodeAs<CStyleCastExpr>("castExpr");
   SourceLocation AssertExpansionLoc = CondStmt->getLocStart();
 
   if (!Opts.CPlusPlus11 || !AssertExpansionLoc.isValid() ||
@@ -74,8 +77,11 @@
       !Condition->isEvaluatable(*ASTCtx))
     return;
 
+  StringRef CastType = CastExpr ?
+      CastExpr->getType().IgnoreParens().getAsString() : "";
+
   // False literal is not the result of macro expansion.
-  if (IsAlwaysFalse) {
+  if (IsAlwaysFalse && (!CastExpr || CastType.endswith("*"))) {
     SourceLocation FalseLiteralLoc =
         SM.getImmediateSpellingLoc(IsAlwaysFalse->getExprLoc());
     if (!FalseLiteralLoc.isMacroID())
@@ -83,7 +89,8 @@
 
     StringRef FalseMacroName =
         Lexer::getImmediateMacroName(FalseLiteralLoc, SM, Opts);
-    if (FalseMacroName.compare_lower("false") == 0)
+    if (FalseMacroName.compare_lower("false") == 0 ||
+        FalseMacroName.compare_lower("null") == 0)
       return;
   }
 
Index: test/clang-tidy/misc-static-assert.cpp
===================================================================
--- test/clang-tidy/misc-static-assert.cpp
+++ test/clang-tidy/misc-static-assert.cpp
@@ -78,6 +78,25 @@
   assert(false && "Don't report me!");
   // CHECK-FIXES: {{^  }}assert(false && "Don't report me!");
 
+#define NULL ((void*)0)
+  assert(NULL && "Don't report me!");
+  // CHECK-FIXES: {{^  }}assert(NULL && "Don't report me!");
+
+  assert(NULL == "Don't report me!");
+  // CHECK-FIXES: {{^  }}assert(NULL == "Don't report me!");
+
+  assert("Don't report me!" == NULL);
+  // CHECK-FIXES: {{^  }}assert("Don't report me!" == NULL);
+
+  assert(0 == "Don't report me!");
+  // CHECK-FIXES: {{^  }}assert(0 == "Don't report me!");
+
+#define NULL ((unsigned int)0)
+  assert(NULL && "Report me!");
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: found assert() that could be
+  // CHECK-FIXES: {{^  }}static_assert(NULL , "Report me!");
+#undef NULL
+
   assert(ZERO_MACRO && "Report me!");
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: found assert() that could be
   // CHECK-FIXES: {{^  }}static_assert(ZERO_MACRO , "Report me!");

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