Merge pull request swiftlang#9215 from drodriguez/undo-9200

Revert "Merge pull request swiftlang#9200 from compnerd/static_assert_false"

Author: drodriguez

clang/lib/Sema/SemaDeclCXX.cpp

@@ -17146,14 +17146,21 @@ Decl *Sema::BuildStaticAssertDeclaration(SourceLocation StaticAssertLoc,
                        FoldKind).isInvalid())
       Failed = true;
 
+    // If the static_assert passes, only verify that
+    // the message is grammatically valid without evaluating it.
+    if (!Failed && AssertMessage && Cond.getBoolValue()) {
+      std::string Str;
+      EvaluateStaticAssertMessageAsString(AssertMessage, Str, Context,
+                                          /*ErrorOnInvalidMessage=*/false);
+    }
+
     // CWG2518
     // [dcl.pre]/p10  If [...] the expression is evaluated in the context of a
     // template definition, the declaration has no effect.
     bool InTemplateDefinition =
         getLangOpts().CPlusPlus && CurContext->isDependentContext();
 
     if (!Failed && !Cond && !InTemplateDefinition) {
-
       SmallString<256> MsgBuffer;
       llvm::raw_svector_ostream Msg(MsgBuffer);
       bool HasMessage = AssertMessage;
@@ -17185,8 +17192,8 @@ Decl *Sema::BuildStaticAssertDeclaration(SourceLocation StaticAssertLoc,
             << InnerCond->getSourceRange();
         DiagnoseStaticAssertDetails(InnerCond);
       } else {
-        Diag(StaticAssertLoc, diag::err_static_assert_failed)
-            << !AssertMessage << Msg.str() << AssertExpr->getSourceRange();
+        Diag(AssertExpr->getBeginLoc(), diag::err_static_assert_failed)
+            << !HasMessage << Msg.str() << AssertExpr->getSourceRange();
         PrintContextStack();
       }
       Failed = true;

clang/test/CXX/drs/dr25xx.cpp

@@ -81,40 +81,6 @@ using ::dr2521::operator""_div;
 #endif
 } // namespace dr2521
 
-namespace dr2518 { // dr2518: 17 review
-
-template <class T>
-void f(T t) {
-  if constexpr (sizeof(T) != sizeof(int)) {
-    static_assert(false, "must be int-sized"); // expected-error {{must be int-size}}
-  }
-}
-
-void g(char c) {
-  f(0);
-  f(c); // expected-note {{requested here}}
-}
-
-template <typename Ty>
-struct S {
-  static_assert(false); // expected-error {{static assertion failed}}
-};
-
-template <>
-struct S<int> {};
-
-template <>
-struct S<float> {};
-
-int test_specialization() {
-  S<int> s1;
-  S<float> s2;
-  S<double> s3; // expected-note {{in instantiation of template class 'dr2518::S<double>' requested here}}
-}
-
-}
-
-
 namespace dr2565 { // dr2565: 16 open
 #if __cplusplus >= 202002L
   template<typename T>