[clang-tidy] misc-static-assert shouldn't flag assert(!"msg")

[fgross]

Summary

Added negated string literals to the set of IsAlwaysFalse expressions to avoid flagging of

assert(!"msg")

[lebedev.ri]

While not directly related to this Differential, i wonder if it would make sense to also not warn on calls to (especially non-member) functions marked with __attribute__((const)), maybe __attribute__((pure)) too.
At least i'm not sure what side-effects such calls may have..

[alexfh]

LG. Thank you!

clang-tools-extra/trunk/clang-tidy/misc/StaticAssertCheck.cpp

StaticAssertCheck::StaticAssertCheck(StringRef Name, ClangTidyContext *Context)
     : ClangTidyCheck(Name, Context) {}
 
 void StaticAssertCheck::registerMatchers(MatchFinder *Finder) {
   // This checker only makes sense for languages that have static assertion
   // capabilities: C++11 and C11.
   if (!(getLangOpts().CPlusPlus11 || getLangOpts().C11))
     return;
 
+  auto NegatedString = unaryOperator(
+      hasOperatorName("!"), hasUnaryOperand(ignoringImpCasts(stringLiteral())));
   auto IsAlwaysFalse =
       expr(anyOf(cxxBoolLiteral(equals(false)), integerLiteral(equals(0)),
-                 cxxNullPtrLiteralExpr(), gnuNullExpr()))
+                 cxxNullPtrLiteralExpr(), gnuNullExpr(), NegatedString))
           .bind("isAlwaysFalse");
   auto IsAlwaysFalseWithCast = ignoringParenImpCasts(anyOf(
       IsAlwaysFalse, cStyleCastExpr(has(ignoringParenImpCasts(IsAlwaysFalse)))
                          .bind("castExpr")));
   auto AssertExprRoot = anyOf(
       binaryOperator(
           anyOf(hasOperatorName("&&"), hasOperatorName("==")),
           hasEitherOperand(ignoringImpCasts(stringLiteral().bind("assertMSG"))),

clang-tools-extra/trunk/test/clang-tidy/misc-static-assert.cpp

int main() {
   // CHECK-FIXES: {{^  }}assert(False);
   assert(FALSE);
   // CHECK-FIXES: {{^  }}assert(FALSE);
 
   assert(ZERO_MACRO);
   // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: found assert() that could be
   // CHECK-FIXES: {{^  }}static_assert(ZERO_MACRO, "");
 
+  assert(!"Don't report me!");
+  // CHECK-FIXES: {{^  }}assert(!"Don't report me!");
+
   assert(0 && "Don't report me!");
   // CHECK-FIXES: {{^  }}assert(0 && "Don't report me!");
 
   assert(false && "Don't report me!");
   // CHECK-FIXES: {{^  }}assert(false && "Don't report me!");
 
 #define NULL ((void*)0)
   assert(NULL && "Don't report me!");