Make static assertions an experimental feature

Author: DougGregor

include/swift/Basic/Features.def

@@ -54,7 +54,6 @@
                       langOpts.hasFeature(#FeatureName))
 #endif
 
-LANGUAGE_FEATURE(StaticAssert, 0, "#assert", langOpts.EnableExperimentalStaticAssert)
 LANGUAGE_FEATURE(AsyncAwait, 296, "async/await", true)
 LANGUAGE_FEATURE(EffectfulProp, 310, "Effectful properties", true)
 LANGUAGE_FEATURE(MarkerProtocol, 0, "@_marker protocol", true)
@@ -84,6 +83,7 @@ SUPPRESSIBLE_LANGUAGE_FEATURE(PrimaryAssociatedTypes2, 346, "Primary associated
 SUPPRESSIBLE_LANGUAGE_FEATURE(UnavailableFromAsync, 0, "@_unavailableFromAsync", true)
 SUPPRESSIBLE_LANGUAGE_FEATURE(NoAsyncAvailability, 340, "@available(*, noasync)", true)
 
+EXPERIMENTAL_FEATURE(StaticAssert)
 EXPERIMENTAL_FEATURE(VariadicGenerics)
 
 #undef EXPERIMENTAL_FEATURE

include/swift/Basic/LangOptions.h

@@ -314,9 +314,6 @@ namespace swift {
     /// Specifies how strict concurrency checking will be.
     StrictConcurrency StrictConcurrencyLevel = StrictConcurrency::Targeted;
 
-    /// Enable experimental #assert feature.
-    bool EnableExperimentalStaticAssert = false;
-
     /// Enable experimental concurrency model.
     bool EnableExperimentalConcurrency = false;
 

lib/Frontend/CompilerInvocation.cpp

@@ -447,9 +447,6 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
   Opts.DiagnosticsEditorMode |= Args.hasArg(OPT_diagnostics_editor_mode,
                                             OPT_serialize_diagnostics_path);
 
-  Opts.EnableExperimentalStaticAssert |=
-    Args.hasArg(OPT_enable_experimental_static_assert);
-
   Opts.EnableExperimentalConcurrency |=
     Args.hasArg(OPT_enable_experimental_concurrency);
 
@@ -664,6 +661,8 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
   // compilers because that's how existing experimental feature flags work.
   if (Args.hasArg(OPT_enable_experimental_variadic_generics))
     Opts.Features.insert(Feature::VariadicGenerics);
+  if (Args.hasArg(OPT_enable_experimental_static_assert))
+    Opts.Features.insert(Feature::StaticAssert);
 
   Opts.EnableAppExtensionRestrictions |= Args.hasArg(OPT_enable_app_extension);
 

lib/Parse/ParseStmt.cpp

@@ -2719,7 +2719,7 @@ ParserResult<Stmt> Parser::parseStmtPoundAssert() {
 
   // We check this after consuming everything, so that the SyntaxContext
   // understands this statement even when the feature is disabled.
-  if (!Context.LangOpts.EnableExperimentalStaticAssert) {
+  if (!Context.LangOpts.hasFeature(Feature::StaticAssert)) {
     diagnose(startLoc, diag::pound_assert_disabled);
     return makeParserError();
   }

lib/SILOptimizer/Mandatory/DataflowDiagnostics.cpp

@@ -271,7 +271,7 @@ class EmitDFDiagnostics : public SILFunctionTransform {
       }
     }
 
-    if (M.getASTContext().LangOpts.EnableExperimentalStaticAssert) {
+    if (M.getASTContext().LangOpts.hasFeature(Feature::StaticAssert)) {
       SymbolicValueBumpAllocator allocator;
       ConstExprEvaluator constantEvaluator(allocator,
                                            getOptions().AssertConfig);

test/Parse/features.swift

@@ -1,5 +1,7 @@
 // RUN: not %target-swift-frontend -typecheck %s 2>&1 | %FileCheck --check-prefix=CHECK-WITHOUT %s 
 // RUN: %target-typecheck-verify-swift -enable-experimental-static-assert
+// RUN: %target-typecheck-verify-swift -enable-experimental-feature StaticAssert
+// REQUIRES: asserts
 
 #if compiler(>=5.3) && $StaticAssert
 #assert(true)

tools/sil-opt/SILOpt.cpp

@@ -574,8 +574,8 @@ int main(int argc, char **argv) {
   Invocation.getLangOptions().OptimizationRemarkMissedPattern =
       createOptRemarkRegex(PassRemarksMissed);
 
-  Invocation.getLangOptions().EnableExperimentalStaticAssert =
-      EnableExperimentalStaticAssert;
+  if (EnableExperimentalStaticAssert)
+    Invocation.getLangOptions().Features.insert(Feature::StaticAssert);
 
   Invocation.getLangOptions().EnableExperimentalDifferentiableProgramming =
       EnableExperimentalDifferentiableProgramming;