[Sema] Ignore "exportability" check for non-public code

Exportability checking logic detects when decls are referenced from API
or inlinable code. This duplicates the check applied for the access
level. Skip the exportability reports about non-public imports and keep
the more familiar access-level check.

Author: xymus

include/swift/AST/DiagnosticsSema.def

@@ -3436,7 +3436,8 @@ ERROR(decl_from_hidden_module,none,
       "it is SPI|"
       "%2 was imported for SPI only|"
       "%2 was not imported by this file|"
-      "C++ types from imported module %2 do not support library evolution}3",
+      "C++ types from imported module %2 do not support library evolution|"
+      "<<ERROR>>}3",
       (const Decl *, unsigned, Identifier, unsigned))
 ERROR(typealias_desugars_to_type_from_hidden_module,none,
       "%0 aliases '%1.%2' and cannot be used %select{here|"
@@ -6567,7 +6568,8 @@ ERROR(inlinable_decl_ref_from_hidden_module,
       "it is SPI|"
       "%2 was imported for SPI only|"
       "%2 was not imported by this file|"
-      "C++ APIs from imported module %2 do not support library evolution}3",
+      "C++ APIs from imported module %2 do not support library evolution|"
+      "<<ERROR>>}3",
       (const ValueDecl *, unsigned, Identifier, unsigned))
 
 WARNING(inlinable_decl_ref_from_hidden_module_warn,

lib/Sema/ResilienceDiagnostics.cpp

@@ -192,6 +192,10 @@ static bool diagnoseValueDeclRefExportability(SourceLoc loc, const ValueDecl *D,
   if (originKind == DisallowedOriginKind::None)
     return false;
 
+  // Access levels from imports are reported with the others access levels.
+  if (originKind == DisallowedOriginKind::NonPublicImport)
+    return false;
+
   auto diagName = D->getName();
   if (auto accessor = dyn_cast<AccessorDecl>(D)) {
     // Only diagnose accessors if their disallowed origin kind differs from