diff --git a/src/harness/fourslash.ts b/src/harness/fourslash.ts
index c05fca5bb47..d852a0b84f3 100644
--- a/src/harness/fourslash.ts
+++ b/src/harness/fourslash.ts
@@ -728,7 +728,7 @@ namespace FourSlash {
             }
         }
 
-        public verifyReferencesAtPositionListContains(fileName: string, start: number, end: number, isWriteAccess?: boolean) {
+        public verifyReferencesAtPositionListContains(fileName: string, start: number, end: number, isWriteAccess?: boolean, isDefinition?: boolean) {
             const references = this.getReferencesAtCaret();
 
             if (!references || references.length === 0) {
@@ -741,11 +741,14 @@ namespace FourSlash {
                     if (typeof isWriteAccess !== "undefined" && reference.isWriteAccess !== isWriteAccess) {
                         this.raiseError(`verifyReferencesAtPositionListContains failed - item isWriteAccess value does not match, actual: ${reference.isWriteAccess}, expected: ${isWriteAccess}.`);
                     }
+                    if (typeof isDefinition !== "undefined" && reference.isDefinition !== isDefinition) {
+                        this.raiseError(`verifyReferencesAtPositionListContains failed - item isDefinition value does not match, actual: ${reference.isDefinition}, expected: ${isDefinition}.`);
+                    }
                     return;
                 }
             }
 
-            const missingItem = { fileName: fileName, start: start, end: end, isWriteAccess: isWriteAccess };
+            const missingItem = { fileName, start, end, isWriteAccess, isDefinition };
             this.raiseError(`verifyReferencesAtPositionListContains failed - could not find the item: ${stringify(missingItem)} in the returned list: (${stringify(references)})`);
         }
 
@@ -2835,8 +2838,8 @@ namespace FourSlashInterface {
             this.state.verifyReferencesCountIs(count, /*localFilesOnly*/ false);
         }
 
-        public referencesAtPositionContains(range: FourSlash.Range, isWriteAccess?: boolean) {
-            this.state.verifyReferencesAtPositionListContains(range.fileName, range.start, range.end, isWriteAccess);
+        public referencesAtPositionContains(range: FourSlash.Range, isWriteAccess?: boolean, isDefinition?: boolean) {
+            this.state.verifyReferencesAtPositionListContains(range.fileName, range.start, range.end, isWriteAccess, isDefinition);
         }
 
         public signatureHelpPresent() {
diff --git a/tests/cases/fourslash/fourslash.ts b/tests/cases/fourslash/fourslash.ts
index 540a6503138..78de5b02358 100644
--- a/tests/cases/fourslash/fourslash.ts
+++ b/tests/cases/fourslash/fourslash.ts
@@ -125,7 +125,7 @@ declare namespace FourSlashInterface {
         completionListAllowsNewIdentifier(): void;
         memberListIsEmpty(): void;
         referencesCountIs(count: number): void;
-        referencesAtPositionContains(range: Range, isWriteAccess?: boolean): void;
+        referencesAtPositionContains(range: Range, isWriteAccess?: boolean, isDefinition?: boolean): void;
         signatureHelpPresent(): void;
         errorExistsBetweenMarkers(startMarker: string, endMarker: string): void;
         errorExistsAfterMarker(markerName?: string): void;
diff --git a/tests/cases/fourslash/getOccurrencesIsDefinitionOfArrowFunction.ts b/tests/cases/fourslash/getOccurrencesIsDefinitionOfArrowFunction.ts
new file mode 100644
index 00000000000..eb9980c946d
--- /dev/null
+++ b/tests/cases/fourslash/getOccurrencesIsDefinitionOfArrowFunction.ts
@@ -0,0 +1,8 @@
+/// <reference path='fourslash.ts' />
+////var [|{| "isDefinition": true |}f|] = x => x + 1;
+////[|{| "isDefinition": false |}f|](12);
+var firstRange = test.ranges()[0];
+goTo.position(firstRange.start, firstRange.fileName);
+test.ranges().forEach(range => {
+    verify.referencesAtPositionContains(range, undefined, range.marker.data.isDefinition);
+});
diff --git a/tests/cases/fourslash/getOccurrencesIsDefinitionOfClass.ts b/tests/cases/fourslash/getOccurrencesIsDefinitionOfClass.ts
new file mode 100644
index 00000000000..04b1f90681a
--- /dev/null
+++ b/tests/cases/fourslash/getOccurrencesIsDefinitionOfClass.ts
@@ -0,0 +1,13 @@
+/// <reference path='fourslash.ts' />
+////class [|{| "isDefinition": true |}C|] {
+////    n: number;
+////    constructor() {
+////        this.n = 12;
+////    }
+////}
+////let c = new [|{| "isDefinition": false |}C|]();
+var firstRange = test.ranges()[0];
+goTo.position(firstRange.start, firstRange.fileName);
+test.ranges().forEach(range => {
+    verify.referencesAtPositionContains(range, undefined, range.marker.data.isDefinition);
+});
diff --git a/tests/cases/fourslash/getOccurrencesIsDefinitionOfEnum.ts b/tests/cases/fourslash/getOccurrencesIsDefinitionOfEnum.ts
new file mode 100644
index 00000000000..a5764206bce
--- /dev/null
+++ b/tests/cases/fourslash/getOccurrencesIsDefinitionOfEnum.ts
@@ -0,0 +1,11 @@
+/// <reference path='fourslash.ts' />
+////enum [|{| "isDefinition": true |}E|] {
+////    First,
+////    Second
+////}
+////let first = [|{| "isDefinition": false |}E|].First;
+var firstRange = test.ranges()[0];
+goTo.position(firstRange.start, firstRange.fileName);
+test.ranges().forEach(range => {
+    verify.referencesAtPositionContains(range, undefined, range.marker.data.isDefinition);
+});
diff --git a/tests/cases/fourslash/getOccurrencesIsDefinitionOfFunction.ts b/tests/cases/fourslash/getOccurrencesIsDefinitionOfFunction.ts
new file mode 100644
index 00000000000..456d953092d
--- /dev/null
+++ b/tests/cases/fourslash/getOccurrencesIsDefinitionOfFunction.ts
@@ -0,0 +1,9 @@
+/// <reference path='fourslash.ts' />
+////function [|{| "isDefinition": true |}func|](x: number) {
+////}
+////[|{| "isDefinition": false |}func|](x)
+var firstRange = test.ranges()[0];
+goTo.position(firstRange.start, firstRange.fileName);
+test.ranges().forEach(range => {
+    verify.referencesAtPositionContains(range, undefined, range.marker.data.isDefinition);
+});
diff --git a/tests/cases/fourslash/getOccurrencesIsDefinitionOfInterface.ts b/tests/cases/fourslash/getOccurrencesIsDefinitionOfInterface.ts
new file mode 100644
index 00000000000..51d1e858185
--- /dev/null
+++ b/tests/cases/fourslash/getOccurrencesIsDefinitionOfInterface.ts
@@ -0,0 +1,10 @@
+/// <reference path='fourslash.ts' />
+////interface [|{| "isDefinition": true |}I|] {
+////    p: number;
+////}
+////let i: [|{| "isDefinition": false |}I|] = { p: 12 };
+var firstRange = test.ranges()[0];
+goTo.position(firstRange.start, firstRange.fileName);
+test.ranges().forEach(range => {
+    verify.referencesAtPositionContains(range, undefined, range.marker.data.isDefinition);
+});
diff --git a/tests/cases/fourslash/getOccurrencesIsDefinitionOfInterfaceClassMerge.ts b/tests/cases/fourslash/getOccurrencesIsDefinitionOfInterfaceClassMerge.ts
new file mode 100644
index 00000000000..7efefa17a4b
--- /dev/null
+++ b/tests/cases/fourslash/getOccurrencesIsDefinitionOfInterfaceClassMerge.ts
@@ -0,0 +1,19 @@
+/// <reference path='fourslash.ts' />
+////interface [|{| "isDefinition": true |}Numbers|] {
+////    p: number;
+////}
+////interface [|{| "isDefinition": true |}Numbers|] {
+////    m: number;
+////}
+////class [|{| "isDefinition": true |}Numbers|] {
+////    f(n: number) {
+////        return this.p + this.m + n;
+////    }
+////}
+////let i: [|{| "isDefinition": false |}Numbers|] = new [|{| "isDefinition": false |}Numbers|]();
+////let x = i.f(i.p + i.m);
+var firstRange = test.ranges()[0];
+goTo.position(firstRange.start, firstRange.fileName);
+test.ranges().forEach(range => {
+    verify.referencesAtPositionContains(range, undefined, range.marker.data.isDefinition);
+});
diff --git a/tests/cases/fourslash/getOccurrencesIsDefinitionOfNamespace.ts b/tests/cases/fourslash/getOccurrencesIsDefinitionOfNamespace.ts
new file mode 100644
index 00000000000..86b92ec9ce7
--- /dev/null
+++ b/tests/cases/fourslash/getOccurrencesIsDefinitionOfNamespace.ts
@@ -0,0 +1,10 @@
+/// <reference path='fourslash.ts' />
+////namespace [|{| "isDefinition": true |}Numbers|] {
+////    export var n = 12;
+////}
+////let x = [|{| "isDefinition": false |}Numbers|].n + 1;
+var firstRange = test.ranges()[0];
+goTo.position(firstRange.start, firstRange.fileName);
+test.ranges().forEach(range => {
+    verify.referencesAtPositionContains(range, undefined, range.marker.data.isDefinition);
+});
diff --git a/tests/cases/fourslash/getOccurrencesIsDefinitionOfParameter.ts b/tests/cases/fourslash/getOccurrencesIsDefinitionOfParameter.ts
new file mode 100644
index 00000000000..cdb0e281d53
--- /dev/null
+++ b/tests/cases/fourslash/getOccurrencesIsDefinitionOfParameter.ts
@@ -0,0 +1,9 @@
+/// <reference path='fourslash.ts' />
+////function f([|{| "isDefinition": true |}x|]: number) {
+////  return [|{| "isDefinition": false |}x|] + 1
+////}
+var firstRange = test.ranges()[0];
+goTo.position(firstRange.start, firstRange.fileName);
+test.ranges().forEach(range => {
+    verify.referencesAtPositionContains(range, undefined, range.marker.data.isDefinition);
+});
diff --git a/tests/cases/fourslash/getOccurrencesIsDefinitionOfTypeAlias.ts b/tests/cases/fourslash/getOccurrencesIsDefinitionOfTypeAlias.ts
new file mode 100644
index 00000000000..44a7c64a93a
--- /dev/null
+++ b/tests/cases/fourslash/getOccurrencesIsDefinitionOfTypeAlias.ts
@@ -0,0 +1,8 @@
+/// <reference path='fourslash.ts' />
+////type [|{| "isDefinition": true |}Alias|]= number;
+////let n: [|{| "isDefinition": false |}Alias|] = 12;
+var firstRange = test.ranges()[0];
+goTo.position(firstRange.start, firstRange.fileName);
+test.ranges().forEach(range => {
+    verify.referencesAtPositionContains(range, undefined, range.marker.data.isDefinition);
+});
diff --git a/tests/cases/fourslash/getOccurrencesIsDefinitionOfVariable.ts b/tests/cases/fourslash/getOccurrencesIsDefinitionOfVariable.ts
new file mode 100644
index 00000000000..8d046c67e3a
--- /dev/null
+++ b/tests/cases/fourslash/getOccurrencesIsDefinitionOfVariable.ts
@@ -0,0 +1,23 @@
+/// <reference path='fourslash.ts' />
+////var [|{| "isDefinition": true |}x|] = 0;
+////var assignmentRightHandSide = [|{| "isDefinition": false |}x|];
+////var assignmentRightHandSide2 = 1 + [|{| "isDefinition": false |}x|];
+////
+////[|{| "isDefinition": false |}x|] = 1;
+////[|{| "isDefinition": false |}x|] = [|{| "isDefinition": false |}x|] + [|{| "isDefinition": false |}x|];
+////
+////[|{| "isDefinition": false |}x|] == 1;
+////[|{| "isDefinition": false |}x|] <= 1;
+////
+////var preIncrement = ++[|{| "isDefinition": false |}x|];
+////var postIncrement = [|{| "isDefinition": false |}x|]++;
+////var preDecrement = --[|{| "isDefinition": false |}x|];
+////var postDecrement = [|{| "isDefinition": false |}x|]--;
+////
+////[|{| "isDefinition": false |}x|] += 1;
+////[|{| "isDefinition": false |}x|] <<= 1;
+var firstRange = test.ranges()[0];
+goTo.position(firstRange.start, firstRange.fileName);
+test.ranges().forEach(range => {
+    verify.referencesAtPositionContains(range, undefined, range.marker.data.isDefinition);
+});