diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 30637c3cebc..eff67197bbc 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -5935,7 +5935,9 @@ namespace ts {
                     // Otherwise, fall back to 'any'.
                     else {
                         if (setter) {
-                            errorOrSuggestion(noImplicitAny, setter, Diagnostics.Property_0_implicitly_has_type_any_because_its_set_accessor_lacks_a_parameter_type_annotation, symbolToString(symbol));
+                            if (!isPrivateWithinAmbient(setter)) {
+                                errorOrSuggestion(noImplicitAny, setter, Diagnostics.Property_0_implicitly_has_type_any_because_its_set_accessor_lacks_a_parameter_type_annotation, symbolToString(symbol));
+                            }
                         }
                         else {
                             Debug.assert(!!getter, "there must existed getter as we are current checking either setter or getter in this function");
@@ -33039,10 +33041,7 @@ namespace ts {
             if (languageVersion < ScriptTarget.ES5) {
                 return grammarErrorOnNode(accessor.name, Diagnostics.Accessors_are_only_available_when_targeting_ECMAScript_5_and_higher);
             }
-            else if (accessor.flags & NodeFlags.Ambient) {
-                return grammarErrorOnNode(accessor.name, Diagnostics.An_accessor_cannot_be_declared_in_an_ambient_context);
-            }
-            else if (accessor.body === undefined && !hasModifier(accessor, ModifierFlags.Abstract)) {
+            else if (accessor.body === undefined && !hasModifier(accessor, ModifierFlags.Abstract) && !(accessor.flags & NodeFlags.Ambient)) {
                 return grammarErrorAtPos(accessor, accessor.end - 1, ";".length, Diagnostics._0_expected, "{");
             }
             else if (accessor.body && hasModifier(accessor, ModifierFlags.Abstract)) {
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 4528d504d0d..5cca456dd49 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -243,10 +243,6 @@
         "category": "Error",
         "code": 1085
     },
-    "An accessor cannot be declared in an ambient context.": {
-        "category": "Error",
-        "code": 1086
-    },
     "'{0}' modifier cannot appear on a constructor declaration.": {
         "category": "Error",
         "code": 1089
diff --git a/tests/baselines/reference/accessorsInAmbientContext.errors.txt b/tests/baselines/reference/accessorsInAmbientContext.errors.txt
deleted file mode 100644
index 44b100bd58d..00000000000
--- a/tests/baselines/reference/accessorsInAmbientContext.errors.txt
+++ /dev/null
@@ -1,44 +0,0 @@
-tests/cases/compiler/accessorsInAmbientContext.ts(3,13): error TS1086: An accessor cannot be declared in an ambient context.
-tests/cases/compiler/accessorsInAmbientContext.ts(4,13): error TS1086: An accessor cannot be declared in an ambient context.
-tests/cases/compiler/accessorsInAmbientContext.ts(6,20): error TS1086: An accessor cannot be declared in an ambient context.
-tests/cases/compiler/accessorsInAmbientContext.ts(7,20): error TS1086: An accessor cannot be declared in an ambient context.
-tests/cases/compiler/accessorsInAmbientContext.ts(12,9): error TS1086: An accessor cannot be declared in an ambient context.
-tests/cases/compiler/accessorsInAmbientContext.ts(13,9): error TS1086: An accessor cannot be declared in an ambient context.
-tests/cases/compiler/accessorsInAmbientContext.ts(15,16): error TS1086: An accessor cannot be declared in an ambient context.
-tests/cases/compiler/accessorsInAmbientContext.ts(16,16): error TS1086: An accessor cannot be declared in an ambient context.
-
-
-==== tests/cases/compiler/accessorsInAmbientContext.ts (8 errors) ====
-    declare module M {
-        class C {
-            get X() { return 1; }
-                ~
-!!! error TS1086: An accessor cannot be declared in an ambient context.
-            set X(v) { }
-                ~
-!!! error TS1086: An accessor cannot be declared in an ambient context.
-    
-            static get Y() { return 1; }
-                       ~
-!!! error TS1086: An accessor cannot be declared in an ambient context.
-            static set Y(v) { }
-                       ~
-!!! error TS1086: An accessor cannot be declared in an ambient context.
-        }
-    }
-    
-    declare class C {
-        get X() { return 1; }
-            ~
-!!! error TS1086: An accessor cannot be declared in an ambient context.
-        set X(v) { }
-            ~
-!!! error TS1086: An accessor cannot be declared in an ambient context.
-    
-        static get Y() { return 1; }
-                   ~
-!!! error TS1086: An accessor cannot be declared in an ambient context.
-        static set Y(v) { }
-                   ~
-!!! error TS1086: An accessor cannot be declared in an ambient context.
-    }
\ No newline at end of file
diff --git a/tests/baselines/reference/ambientGetters.errors.txt b/tests/baselines/reference/ambientGetters.errors.txt
deleted file mode 100644
index b245f561813..00000000000
--- a/tests/baselines/reference/ambientGetters.errors.txt
+++ /dev/null
@@ -1,16 +0,0 @@
-tests/cases/compiler/ambientGetters.ts(2,9): error TS1086: An accessor cannot be declared in an ambient context.
-tests/cases/compiler/ambientGetters.ts(6,9): error TS1086: An accessor cannot be declared in an ambient context.
-
-
-==== tests/cases/compiler/ambientGetters.ts (2 errors) ====
-    declare class A {
-        get length() : number;
-            ~~~~~~
-!!! error TS1086: An accessor cannot be declared in an ambient context.
-    }
-    
-    declare class B {
-        get length() { return 0; }
-            ~~~~~~
-!!! error TS1086: An accessor cannot be declared in an ambient context.
-    }
\ No newline at end of file
diff --git a/tests/baselines/reference/parserAccessors5.errors.txt b/tests/baselines/reference/parserAccessors5.errors.txt
deleted file mode 100644
index b7dcd8ef923..00000000000
--- a/tests/baselines/reference/parserAccessors5.errors.txt
+++ /dev/null
@@ -1,9 +0,0 @@
-tests/cases/conformance/parser/ecmascript5/Accessors/parserAccessors5.ts(2,7): error TS1086: An accessor cannot be declared in an ambient context.
-
-
-==== tests/cases/conformance/parser/ecmascript5/Accessors/parserAccessors5.ts (1 errors) ====
-    declare class C {
-      get foo() { return 0; }
-          ~~~
-!!! error TS1086: An accessor cannot be declared in an ambient context.
-    }
\ No newline at end of file
diff --git a/tests/baselines/reference/parserAccessors6.errors.txt b/tests/baselines/reference/parserAccessors6.errors.txt
deleted file mode 100644
index 023ec6d79c3..00000000000
--- a/tests/baselines/reference/parserAccessors6.errors.txt
+++ /dev/null
@@ -1,9 +0,0 @@
-tests/cases/conformance/parser/ecmascript5/Accessors/parserAccessors6.ts(2,7): error TS1086: An accessor cannot be declared in an ambient context.
-
-
-==== tests/cases/conformance/parser/ecmascript5/Accessors/parserAccessors6.ts (1 errors) ====
-    declare class C {
-      set foo(v) { }
-          ~~~
-!!! error TS1086: An accessor cannot be declared in an ambient context.
-    }
\ No newline at end of file
diff --git a/tests/baselines/reference/parserComputedPropertyName23.errors.txt b/tests/baselines/reference/parserComputedPropertyName23.errors.txt
index 8c95992253c..2ecf45eb697 100644
--- a/tests/baselines/reference/parserComputedPropertyName23.errors.txt
+++ b/tests/baselines/reference/parserComputedPropertyName23.errors.txt
@@ -1,12 +1,9 @@
-tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName23.ts(2,9): error TS1086: An accessor cannot be declared in an ambient context.
 tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName23.ts(2,10): error TS2304: Cannot find name 'e'.
 
 
-==== tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName23.ts (2 errors) ====
+==== tests/cases/conformance/parser/ecmascript6/ComputedPropertyNames/parserComputedPropertyName23.ts (1 errors) ====
     declare class C {
         get [e](): number 
-            ~~~
-!!! error TS1086: An accessor cannot be declared in an ambient context.
              ~
 !!! error TS2304: Cannot find name 'e'.
     }
\ No newline at end of file