diff --git a/src/compiler/declarationEmitter.ts b/src/compiler/declarationEmitter.ts
index d5ea403e111..f05a9143809 100644
--- a/src/compiler/declarationEmitter.ts
+++ b/src/compiler/declarationEmitter.ts
@@ -317,7 +317,7 @@ namespace ts {
         function reportIllegalExtends() {
             if (errorNameNode) {
                 reportedDeclarationError = true;
-                emitterDiagnostics.add(createDiagnosticForNode(errorNameNode, Diagnostics.Extends_clause_of_exported_class_0_refers_to_a_type_with_no_declaration,
+                emitterDiagnostics.add(createDiagnosticForNode(errorNameNode, Diagnostics.Extends_clause_of_exported_class_0_refers_to_a_type_whose_name_cannot_be_referenced,
                     declarationNameToString(errorNameNode)));
             }
         }
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index befdd5cfe43..e477f1528e3 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -2352,7 +2352,7 @@
         "category": "Error",
         "code": 4092
     },
-    "Extends clause of exported class '{0}' refers to a type with no declaration.": {
+    "Extends clause of exported class '{0}' refers to a type whose name cannot be referenced.": {
         "category": "Error",
         "code": 4093
     },
diff --git a/tests/baselines/reference/declarationEmitExpressionInExtends4.errors.txt b/tests/baselines/reference/declarationEmitExpressionInExtends4.errors.txt
index 3d2c6689b74..80e815c5611 100644
--- a/tests/baselines/reference/declarationEmitExpressionInExtends4.errors.txt
+++ b/tests/baselines/reference/declarationEmitExpressionInExtends4.errors.txt
@@ -1,7 +1,7 @@
 tests/cases/compiler/declarationEmitExpressionInExtends4.ts(2,10): error TS4060: Return type of exported function has or is using private name 'D'.
-tests/cases/compiler/declarationEmitExpressionInExtends4.ts(6,7): error TS4093: Extends clause of exported class 'C' refers to a type with no declaration.
+tests/cases/compiler/declarationEmitExpressionInExtends4.ts(6,7): error TS4093: Extends clause of exported class 'C' refers to a type whose name cannot be referenced.
 tests/cases/compiler/declarationEmitExpressionInExtends4.ts(6,17): error TS2315: Type 'D' is not generic.
-tests/cases/compiler/declarationEmitExpressionInExtends4.ts(10,7): error TS4093: Extends clause of exported class 'C2' refers to a type with no declaration.
+tests/cases/compiler/declarationEmitExpressionInExtends4.ts(10,7): error TS4093: Extends clause of exported class 'C2' refers to a type whose name cannot be referenced.
 tests/cases/compiler/declarationEmitExpressionInExtends4.ts(10,18): error TS2304: Cannot find name 'SomeUndefinedFunction'.
 tests/cases/compiler/declarationEmitExpressionInExtends4.ts(15,18): error TS2304: Cannot find name 'SomeUndefinedFunction'.
 tests/cases/compiler/declarationEmitExpressionInExtends4.ts(15,18): error TS4020: Extends clause of exported class 'C3' has or is using private name 'SomeUndefinedFunction'.
@@ -17,7 +17,7 @@ tests/cases/compiler/declarationEmitExpressionInExtends4.ts(15,18): error TS4020
     
     class C extends getSomething()<number, string> {
           ~
-!!! error TS4093: Extends clause of exported class 'C' refers to a type with no declaration.
+!!! error TS4093: Extends clause of exported class 'C' refers to a type whose name cannot be referenced.
                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2315: Type 'D' is not generic.
     
@@ -25,7 +25,7 @@ tests/cases/compiler/declarationEmitExpressionInExtends4.ts(15,18): error TS4020
     
     class C2 extends SomeUndefinedFunction()<number, string> {
           ~~
-!!! error TS4093: Extends clause of exported class 'C2' refers to a type with no declaration.
+!!! error TS4093: Extends clause of exported class 'C2' refers to a type whose name cannot be referenced.
                      ~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2304: Cannot find name 'SomeUndefinedFunction'.
     
diff --git a/tests/baselines/reference/exportClassExtendingIntersection.errors.txt b/tests/baselines/reference/exportClassExtendingIntersection.errors.txt
index 774376a0265..8464d0691c0 100644
--- a/tests/baselines/reference/exportClassExtendingIntersection.errors.txt
+++ b/tests/baselines/reference/exportClassExtendingIntersection.errors.txt
@@ -1,4 +1,4 @@
-tests/cases/compiler/FinalClass.ts(4,14): error TS4093: Extends clause of exported class 'MyExtendedClass' refers to a type with no declaration.
+tests/cases/compiler/FinalClass.ts(4,14): error TS4093: Extends clause of exported class 'MyExtendedClass' refers to a type whose name cannot be referenced.
 
 
 ==== tests/cases/compiler/BaseClass.ts (0 errors) ====
@@ -26,7 +26,7 @@ tests/cases/compiler/FinalClass.ts(4,14): error TS4093: Extends clause of export
     
     export class MyExtendedClass extends MyMixin(MyBaseClass)<string> {
                  ~~~~~~~~~~~~~~~
-!!! error TS4093: Extends clause of exported class 'MyExtendedClass' refers to a type with no declaration.
+!!! error TS4093: Extends clause of exported class 'MyExtendedClass' refers to a type whose name cannot be referenced.
         extendedClassProperty: number;
     }
 ==== tests/cases/compiler/Main.ts (0 errors) ====
diff --git a/tests/baselines/reference/mixinAccessModifiers.errors.txt b/tests/baselines/reference/mixinAccessModifiers.errors.txt
index 22cfab4e0e4..cacdeef6d54 100644
--- a/tests/baselines/reference/mixinAccessModifiers.errors.txt
+++ b/tests/baselines/reference/mixinAccessModifiers.errors.txt
@@ -5,20 +5,20 @@ tests/cases/conformance/classes/mixinAccessModifiers.ts(51,4): error TS2445: Pro
 tests/cases/conformance/classes/mixinAccessModifiers.ts(66,7): error TS2415: Class 'C1' incorrectly extends base class 'Private & Private2'.
   Type 'C1' is not assignable to type 'Private'.
     Property 'p' has conflicting declarations and is inaccessible in type 'C1'.
-tests/cases/conformance/classes/mixinAccessModifiers.ts(66,7): error TS4093: Extends clause of exported class 'C1' refers to a type with no declaration.
+tests/cases/conformance/classes/mixinAccessModifiers.ts(66,7): error TS4093: Extends clause of exported class 'C1' refers to a type whose name cannot be referenced.
 tests/cases/conformance/classes/mixinAccessModifiers.ts(67,7): error TS2415: Class 'C2' incorrectly extends base class 'Private & Protected'.
   Type 'C2' is not assignable to type 'Private'.
     Property 'p' has conflicting declarations and is inaccessible in type 'C2'.
-tests/cases/conformance/classes/mixinAccessModifiers.ts(67,7): error TS4093: Extends clause of exported class 'C2' refers to a type with no declaration.
+tests/cases/conformance/classes/mixinAccessModifiers.ts(67,7): error TS4093: Extends clause of exported class 'C2' refers to a type whose name cannot be referenced.
 tests/cases/conformance/classes/mixinAccessModifiers.ts(68,7): error TS2415: Class 'C3' incorrectly extends base class 'Private & Public'.
   Type 'C3' is not assignable to type 'Private'.
     Property 'p' has conflicting declarations and is inaccessible in type 'C3'.
-tests/cases/conformance/classes/mixinAccessModifiers.ts(68,7): error TS4093: Extends clause of exported class 'C3' refers to a type with no declaration.
-tests/cases/conformance/classes/mixinAccessModifiers.ts(70,7): error TS4093: Extends clause of exported class 'C4' refers to a type with no declaration.
-tests/cases/conformance/classes/mixinAccessModifiers.ts(83,7): error TS4093: Extends clause of exported class 'C5' refers to a type with no declaration.
+tests/cases/conformance/classes/mixinAccessModifiers.ts(68,7): error TS4093: Extends clause of exported class 'C3' refers to a type whose name cannot be referenced.
+tests/cases/conformance/classes/mixinAccessModifiers.ts(70,7): error TS4093: Extends clause of exported class 'C4' refers to a type whose name cannot be referenced.
+tests/cases/conformance/classes/mixinAccessModifiers.ts(83,7): error TS4093: Extends clause of exported class 'C5' refers to a type whose name cannot be referenced.
 tests/cases/conformance/classes/mixinAccessModifiers.ts(85,6): error TS2445: Property 'p' is protected and only accessible within class 'C4' and its subclasses.
 tests/cases/conformance/classes/mixinAccessModifiers.ts(90,6): error TS2445: Property 's' is protected and only accessible within class 'typeof C4' and its subclasses.
-tests/cases/conformance/classes/mixinAccessModifiers.ts(96,7): error TS4093: Extends clause of exported class 'C6' refers to a type with no declaration.
+tests/cases/conformance/classes/mixinAccessModifiers.ts(96,7): error TS4093: Extends clause of exported class 'C6' refers to a type whose name cannot be referenced.
 tests/cases/conformance/classes/mixinAccessModifiers.ts(98,6): error TS2445: Property 'p' is protected and only accessible within class 'C4' and its subclasses.
 tests/cases/conformance/classes/mixinAccessModifiers.ts(103,6): error TS2445: Property 's' is protected and only accessible within class 'typeof C4' and its subclasses.
 
@@ -103,25 +103,25 @@ tests/cases/conformance/classes/mixinAccessModifiers.ts(103,6): error TS2445: Pr
 !!! error TS2415:   Type 'C1' is not assignable to type 'Private'.
 !!! error TS2415:     Property 'p' has conflicting declarations and is inaccessible in type 'C1'.
           ~~
-!!! error TS4093: Extends clause of exported class 'C1' refers to a type with no declaration.
+!!! error TS4093: Extends clause of exported class 'C1' refers to a type whose name cannot be referenced.
     class C2 extends Mix(Private, Protected) {}
           ~~
 !!! error TS2415: Class 'C2' incorrectly extends base class 'Private & Protected'.
 !!! error TS2415:   Type 'C2' is not assignable to type 'Private'.
 !!! error TS2415:     Property 'p' has conflicting declarations and is inaccessible in type 'C2'.
           ~~
-!!! error TS4093: Extends clause of exported class 'C2' refers to a type with no declaration.
+!!! error TS4093: Extends clause of exported class 'C2' refers to a type whose name cannot be referenced.
     class C3 extends Mix(Private, Public) {}
           ~~
 !!! error TS2415: Class 'C3' incorrectly extends base class 'Private & Public'.
 !!! error TS2415:   Type 'C3' is not assignable to type 'Private'.
 !!! error TS2415:     Property 'p' has conflicting declarations and is inaccessible in type 'C3'.
           ~~
-!!! error TS4093: Extends clause of exported class 'C3' refers to a type with no declaration.
+!!! error TS4093: Extends clause of exported class 'C3' refers to a type whose name cannot be referenced.
     
     class C4 extends Mix(Protected, Protected2) {
           ~~
-!!! error TS4093: Extends clause of exported class 'C4' refers to a type with no declaration.
+!!! error TS4093: Extends clause of exported class 'C4' refers to a type whose name cannot be referenced.
     	f(c4: C4, c5: C5, c6: C6) {
     		c4.p;
     		c5.p;
@@ -136,7 +136,7 @@ tests/cases/conformance/classes/mixinAccessModifiers.ts(103,6): error TS2445: Pr
     
     class C5 extends Mix(Protected, Public) {
           ~~
-!!! error TS4093: Extends clause of exported class 'C5' refers to a type with no declaration.
+!!! error TS4093: Extends clause of exported class 'C5' refers to a type whose name cannot be referenced.
     	f(c4: C4, c5: C5, c6: C6) {
     		c4.p;  // Error, not in class deriving from Protected2
     		   ~
@@ -155,7 +155,7 @@ tests/cases/conformance/classes/mixinAccessModifiers.ts(103,6): error TS2445: Pr
     
     class C6 extends Mix(Public, Public2) {
           ~~
-!!! error TS4093: Extends clause of exported class 'C6' refers to a type with no declaration.
+!!! error TS4093: Extends clause of exported class 'C6' refers to a type whose name cannot be referenced.
     	f(c4: C4, c5: C5, c6: C6) {
     		c4.p;  // Error, not in class deriving from Protected2
     		   ~