[Sema] Error on aliases desugaring to a reference SPI only imported

There are only new users of @_spiOnly so we can already make this
diagnostic an error.

Author: xymus

lib/Sema/ResilienceDiagnostics.cpp

@@ -132,15 +132,17 @@ static bool diagnoseTypeAliasDeclRefExportability(SourceLoc loc,
                   TAD->getName(), definingModule->getNameStr(), D->getNameStr(),
                   static_cast<unsigned>(*reason), definingModule->getName(),
                   static_cast<unsigned>(originKind))
-        .warnUntilSwiftVersion(6);
+        .warnUntilSwiftVersionIf(originKind != DisallowedOriginKind::SPIOnly,
+                                 6);
   } else {
     ctx.Diags
         .diagnose(loc,
                   diag::inlinable_typealias_desugars_to_type_from_hidden_module,
                   TAD->getName(), definingModule->getNameStr(), D->getNameStr(),
                   fragileKind.getSelector(), definingModule->getName(),
                   static_cast<unsigned>(originKind))
-        .warnUntilSwiftVersion(6);
+        .warnUntilSwiftVersionIf(originKind != DisallowedOriginKind::SPIOnly,
+                                 6);
   }
   D->diagnose(diag::kind_declared_here, DescriptiveDeclKind::Type);
 

test/Sema/implicit-import-typealias.swift

@@ -9,6 +9,7 @@
 
 // RUN: %target-swift-frontend -typecheck -verify %t/UsesAliasesNoImport.swift -I %t
 // RUN: %target-swift-frontend -typecheck -verify %t/UsesAliasesImplementationOnlyImport.swift -I %t
+// RUN: %target-swift-frontend -typecheck -verify %t/UsesAliasesSPIOnlyImport.swift -I %t -experimental-spi-only-imports
 // RUN: %target-swift-frontend -typecheck -verify %t/UsesAliasesWithImport.swift  -I %t
 
 /// The swiftinterface is broken by the missing import without the workaround.
@@ -101,6 +102,20 @@ import Aliases
 public func takesGeneric<T: ProtoAlias>(_ t: T) {}
 
 
+//--- UsesAliasesSPIOnlyImport.swift
+
+import Aliases
+@_spiOnly import Original
+
+@inlinable public func inlinableFunc() {
+  // expected-error@+1 {{'StructAlias' aliases 'Original.Struct' and cannot be used in an '@inlinable' function because 'Original' was imported for SPI only}}
+  _ = StructAlias.self
+}
+
+// expected-error@+1 {{'ProtoAlias' aliases 'Original.Proto' and cannot be used here because 'Original' was imported for SPI only}}
+public func takesGeneric<T: ProtoAlias>(_ t: T) {}
+
+
 //--- UsesAliasesWithImport.swift
 
 import Aliases