[jextract] Update for review feedback

Sources/JExtractSwift/CDeclLowering/Swift2JavaTranslator+FunctionLowering.swift

@@ -50,8 +50,8 @@ extension Swift2JavaTranslator {
   }
 
   /// Lower the given variable decl to a C-compatible entrypoint,
-  /// providing all of the mappings between the parameter and result types
-  /// of the original function and its `@_cdecl` counterpart.
+  /// providing the mappings between the `self` and value type of the variable
+  /// and its `@_cdecl` counterpart.
   @_spi(Testing)
   public func lowerFunctionSignature(
     _ decl: VariableDeclSyntax,
@@ -297,7 +297,7 @@ struct CdeclLowering {
     }
   }
 
-  /// Lower a Swift result type to cdecl parameters and return type.
+  /// Lower a Swift result type to cdecl out parameters and return type.
   ///
   /// - Parameters:
   ///   - type: The return type.

Sources/JExtractSwift/SwiftTypes/SwiftFunctionSignature.swift

@@ -227,26 +227,17 @@ extension VariableDeclSyntax {
       case .getter:
         return [.get]
       case .accessors(let accessors):
-        var hasGetter = false
-        var hasSetter = false
-
         for accessor in accessors {
-          switch accessor.accessorSpecifier {
-          case .keyword(.get), .keyword(._read), .keyword(.unsafeAddress):
-            hasGetter = true
-          case .keyword(.set), .keyword(._modify), .keyword(.unsafeMutableAddress):
-            hasSetter = true
+          switch accessor.accessorSpecifier.tokenKind {
+            // Existence of any write accessor or observer implies this supports read/write.
+          case .keyword(.set), .keyword(._modify), .keyword(.unsafeMutableAddress),
+              .keyword(.willSet), .keyword(.didSet):
+            return [.get, .set]
           default: // Ignore willSet/didSet and unknown accessors.
             break
           }
         }
-
-        switch (hasGetter, hasSetter) {
-        case (true, true): return [.get, .set]
-        case (true, false): return [.get]
-        case (false, true): return [.set]
-        case (false, false): break
-        }
+        return [.get]
       }
     }