Initial setup

Author: RyanCavanaugh

Diff for: src/compiler/checker.ts

@@ -32323,16 +32323,13 @@ namespace ts {
                     if (otherAccessor) {
                         const nodeFlags = getEffectiveModifierFlags(node);
                         const otherFlags = getEffectiveModifierFlags(otherAccessor);
-                        if ((nodeFlags & ModifierFlags.AccessibilityModifier) !== (otherFlags & ModifierFlags.AccessibilityModifier)) {
-                            error(node.name, Diagnostics.Getter_and_setter_accessors_do_not_agree_in_visibility);
-                        }
                         if ((nodeFlags & ModifierFlags.Abstract) !== (otherFlags & ModifierFlags.Abstract)) {
                             error(node.name, Diagnostics.Accessors_must_both_be_abstract_or_non_abstract);
                         }
 
                         // TypeScript 1.0 spec (April 2014): 4.5
                         // If both accessors include type annotations, the specified types must be identical.
-                        checkAccessorDeclarationTypesIdentical(node, otherAccessor, getAnnotatedAccessorType, Diagnostics.get_and_set_accessor_must_have_the_same_type);
+                        checkAccessorDeclarationTypesAssignable(node, otherAccessor, getAnnotatedAccessorType, Diagnostics.get_and_set_accessor_must_have_the_comparable_types);
                         checkAccessorDeclarationTypesIdentical(node, otherAccessor, getThisTypeOfDeclaration, Diagnostics.get_and_set_accessor_must_have_the_same_this_type);
                     }
                 }
@@ -32345,13 +32342,22 @@ namespace ts {
         }
 
         function checkAccessorDeclarationTypesIdentical(first: AccessorDeclaration, second: AccessorDeclaration, getAnnotatedType: (a: AccessorDeclaration) => Type | undefined, message: DiagnosticMessage) {
+            return checkAccessorDeclarationTypesMatch(first, second, getAnnotatedType, isTypeIdenticalTo, message);
+        }
+
+        function checkAccessorDeclarationTypesAssignable(first: AccessorDeclaration, second: AccessorDeclaration, getAnnotatedType: (a: AccessorDeclaration) => Type | undefined, message: DiagnosticMessage) {
+            return checkAccessorDeclarationTypesMatch(first, second, getAnnotatedType, areTypesComparable, message);
+        }
+
+        function checkAccessorDeclarationTypesMatch(first: AccessorDeclaration, second: AccessorDeclaration, getAnnotatedType: (a: AccessorDeclaration) => Type | undefined, match: typeof areTypesComparable, message: DiagnosticMessage) {
             const firstType = getAnnotatedType(first);
             const secondType = getAnnotatedType(second);
-            if (firstType && secondType && !isTypeIdenticalTo(firstType, secondType)) {
+            if (firstType && secondType && !match(firstType, secondType)) {
                 error(first, message);
             }
         }
 
+
         function checkMissingDeclaration(node: Node) {
             checkDecorators(node);
         }

Diff for: src/compiler/diagnosticMessages.json

@@ -1697,11 +1697,7 @@
         "category": "Error",
         "code": 2378
     },
-    "Getter and setter accessors do not agree in visibility.": {
-        "category": "Error",
-        "code": 2379
-    },
-    "'get' and 'set' accessor must have the same type.": {
+    "'get' and 'set' accessor must have comparable types.": {
         "category": "Error",
         "code": 2380
     },