AST: Re-baseline BuiltinEmplaceTypedThrows feature.

Author: tshortli

include/swift/Basic/Features.def

@@ -254,9 +254,9 @@ CONDITIONALLY_SUPPRESSIBLE_LANGUAGE_FEATURE(IsolatedAny, 431, "@isolated(any) fu
 LANGUAGE_FEATURE(IsolatedAny2, 431, "@isolated(any) function types")
 LANGUAGE_FEATURE(ObjCImplementation, 436, "@objc @implementation extensions")
 LANGUAGE_FEATURE(NonescapableTypes, 446, "Nonescapable types")
-LANGUAGE_FEATURE(BuiltinEmplaceTypedThrows, 0, "Builtin.emplace typed throws")
 SUPPRESSIBLE_LANGUAGE_FEATURE(MemorySafetyAttributes, 458, "@unsafe attribute")
 LANGUAGE_FEATURE(ValueGenerics, 452, "Value generics feature (integer generics)")
+BASELINE_LANGUAGE_FEATURE(BuiltinEmplaceTypedThrows, 0, "Builtin.emplace typed throws")
 LANGUAGE_FEATURE(RawIdentifiers, 451, "Raw identifiers")
 LANGUAGE_FEATURE(SendableCompletionHandlers, 463, "Objective-C completion handler parameters are imported as @Sendable")
 LANGUAGE_FEATURE(AsyncExecutionBehaviorAttributes, 0, "@concurrent and nonisolated(nonsending)")

lib/AST/FeatureSet.cpp

@@ -612,11 +612,6 @@ static bool usesFeatureCustomAvailability(Decl *decl) {
   return false;
 }
 
-static bool usesFeatureBuiltinEmplaceTypedThrows(Decl *decl) {
-  // Callers of 'Builtin.emplace' should explicitly guard the usage with #if.
-  return false;
-}
-
 static bool usesFeatureAsyncExecutionBehaviorAttributes(Decl *decl) {
   // Explicit `@concurrent` attribute on the declaration.
   if (decl->getAttrs().hasAttribute<ConcurrentAttr>())

stdlib/public/core/InlineArray.swift

@@ -215,7 +215,6 @@ extension InlineArray where Element: ~Copyable {
   @available(SwiftStdlib 6.2, *)
   @_alwaysEmitIntoClient
   public init<E: Error>(_ body: (Index) throws(E) -> Element) throws(E) {
-#if $BuiltinEmplaceTypedThrows
     _storage = try Builtin.emplace { (rawPtr) throws(E) -> () in
       let buffer = unsafe Self._initializationBuffer(start: rawPtr)
 
@@ -234,9 +233,6 @@ extension InlineArray where Element: ~Copyable {
         }
       }
     }
-#else
-    fatalError()
-#endif
   }
 
   /// Initializes every element in this array, by calling the given closure
@@ -264,7 +260,6 @@ extension InlineArray where Element: ~Copyable {
     first: consuming Element,
     next: (borrowing Element) throws(E) -> Element
   ) throws(E) {
-#if $BuiltinEmplaceTypedThrows
     // FIXME: We should be able to mark 'Builtin.emplace' as '@once' or something
     //        to give the compiler enough information to know we will only run
     //        it once so it can consume the capture. For now, we use an optional
@@ -298,17 +293,13 @@ extension InlineArray where Element: ~Copyable {
         }
       }
     }
-#else
-    fatalError()
-#endif
   }
 
   @available(SwiftStdlib 6.2, *)
   @_alwaysEmitIntoClient
   public init<E: Error>(
     initializingWith initializer: (inout OutputSpan<Element>) throws(E) -> Void
   ) throws(E) {
-#if $BuiltinEmplaceTypedThrows
     _storage = try Builtin.emplace { (rawPtr) throws(E) -> () in
       let buffer = unsafe Self._initializationBuffer(start: rawPtr)
       _internalInvariant(Self.count == buffer.count)
@@ -317,9 +308,6 @@ extension InlineArray where Element: ~Copyable {
       let initialized = unsafe output.finalize(for: buffer)
       _precondition(count == initialized, "InlineArray initialization underflow")
     }
-#else
-    fatalError()
-#endif
   }
 }