diff --git a/src/harness/client.ts b/src/harness/client.ts
index f85e0e111317d..537ee3f36a0b3 100644
--- a/src/harness/client.ts
+++ b/src/harness/client.ts
@@ -306,7 +306,8 @@ namespace ts.server {
                     fileName: entry.file,
                     textSpan: this.decodeSpan(entry),
                     kind: ScriptElementKind.unknown,
-                    name: ""
+                    name: "",
+                    unverified: entry.unverified,
                 })),
                 textSpan: this.decodeSpan(body.textSpan, request.arguments.file)
             };
diff --git a/src/harness/fourslashImpl.ts b/src/harness/fourslashImpl.ts
index a39e4525fd617..42917467727e4 100644
--- a/src/harness/fourslashImpl.ts
+++ b/src/harness/fourslashImpl.ts
@@ -685,10 +685,10 @@ namespace FourSlash {
         }
 
         public verifyGoToDefinitionIs(endMarker: ArrayOrSingle<string>) {
-            this.verifyGoToXWorker(toArray(endMarker), () => this.getGoToDefinition());
+            this.verifyGoToXWorker(/*startMarker*/ undefined, toArray(endMarker), () => this.getGoToDefinition());
         }
 
-        public verifyGoToDefinition(arg0: any, endMarkerNames?: ArrayOrSingle<string> | { file: string }) {
+        public verifyGoToDefinition(arg0: any, endMarkerNames?: ArrayOrSingle<string | { marker: string, unverified?: boolean }> | { file: string, unverified?: boolean }) {
             this.verifyGoToX(arg0, endMarkerNames, () => this.getGoToDefinitionAndBoundSpan());
         }
 
@@ -705,7 +705,7 @@ namespace FourSlash {
                 this.languageService.getTypeDefinitionAtPosition(this.activeFile.fileName, this.currentCaretPosition));
         }
 
-        private verifyGoToX(arg0: any, endMarkerNames: ArrayOrSingle<string> | { file: string } | undefined, getDefs: () => readonly ts.DefinitionInfo[] | ts.DefinitionInfoAndBoundSpan | undefined) {
+        private verifyGoToX(arg0: any, endMarkerNames: ArrayOrSingle<string | { marker: string, unverified?: boolean }> | { file: string, unverified?: boolean } | undefined, getDefs: () => readonly ts.DefinitionInfo[] | ts.DefinitionInfoAndBoundSpan | undefined) {
             if (endMarkerNames) {
                 this.verifyGoToXPlain(arg0, endMarkerNames, getDefs);
             }
@@ -725,7 +725,7 @@ namespace FourSlash {
             }
         }
 
-        private verifyGoToXPlain(startMarkerNames: ArrayOrSingle<string>, endMarkerNames: ArrayOrSingle<string> | { file: string }, getDefs: () => readonly ts.DefinitionInfo[] | ts.DefinitionInfoAndBoundSpan | undefined) {
+        private verifyGoToXPlain(startMarkerNames: ArrayOrSingle<string>, endMarkerNames: ArrayOrSingle<string | { marker: string, unverified?: boolean }> | { file: string, unverified?: boolean }, getDefs: () => readonly ts.DefinitionInfo[] | ts.DefinitionInfoAndBoundSpan | undefined) {
             for (const start of toArray(startMarkerNames)) {
                 this.verifyGoToXSingle(start, endMarkerNames, getDefs);
             }
@@ -737,12 +737,12 @@ namespace FourSlash {
             }
         }
 
-        private verifyGoToXSingle(startMarkerName: string, endMarkerNames: ArrayOrSingle<string> | { file: string }, getDefs: () => readonly ts.DefinitionInfo[] | ts.DefinitionInfoAndBoundSpan | undefined) {
+        private verifyGoToXSingle(startMarkerName: string, endMarkerNames: ArrayOrSingle<string | { marker: string, unverified?: boolean }> | { file: string, unverified?: boolean }, getDefs: () => readonly ts.DefinitionInfo[] | ts.DefinitionInfoAndBoundSpan | undefined) {
             this.goToMarker(startMarkerName);
-            this.verifyGoToXWorker(toArray(endMarkerNames), getDefs, startMarkerName);
+            this.verifyGoToXWorker(startMarkerName, toArray(endMarkerNames), getDefs, startMarkerName);
         }
 
-        private verifyGoToXWorker(endMarkers: readonly (string | { file: string })[], getDefs: () => readonly ts.DefinitionInfo[] | ts.DefinitionInfoAndBoundSpan | undefined, startMarkerName?: string) {
+        private verifyGoToXWorker(startMarker: string | undefined, endMarkers: readonly (string | { marker?: string, file?: string, unverified?: boolean })[], getDefs: () => readonly ts.DefinitionInfo[] | ts.DefinitionInfoAndBoundSpan | undefined, startMarkerName?: string) {
             const defs = getDefs();
             let definitions: readonly ts.DefinitionInfo[];
             let testName: string;
@@ -763,8 +763,11 @@ namespace FourSlash {
             }
 
             ts.zipWith(endMarkers, definitions, (endMarkerOrFileResult, definition, i) => {
-                const expectedFileName = typeof endMarkerOrFileResult === "string" ? this.getMarkerByName(endMarkerOrFileResult).fileName : endMarkerOrFileResult.file;
-                const expectedPosition = typeof endMarkerOrFileResult === "string" ? this.getMarkerByName(endMarkerOrFileResult).position : 0;
+                const markerName = typeof endMarkerOrFileResult === "string" ? endMarkerOrFileResult : endMarkerOrFileResult.marker;
+                const marker = markerName !== undefined ? this.getMarkerByName(markerName) : undefined;
+                const expectedFileName = marker?.fileName || typeof endMarkerOrFileResult !== "string" && endMarkerOrFileResult.file;
+                ts.Debug.assert(typeof expectedFileName === "string");
+                const expectedPosition = marker?.position || 0;
                 if (ts.comparePaths(expectedFileName, definition.fileName, /*ignoreCase*/ true) !== ts.Comparison.EqualTo || expectedPosition !== definition.textSpan.start) {
                     const filesToDisplay = ts.deduplicate([expectedFileName, definition.fileName], ts.equateValues);
                     const markers = [{ text: "EXPECTED", fileName: expectedFileName, position: expectedPosition }, { text: "ACTUAL", fileName: definition.fileName, position: definition.textSpan.start }];
@@ -777,7 +780,15 @@ namespace FourSlash {
                         return `// @Filename: ${fileName}\n${fileContent}`;
                     }).join("\n\n");
 
-                    this.raiseError(`${testName} failed for definition ${endMarkerOrFileResult} (${i}): expected ${expectedFileName} at ${expectedPosition}, got ${definition.fileName} at ${definition.textSpan.start}\n\n${text}\n`);
+                    this.raiseError(`${testName} failed for definition ${markerName || expectedFileName} (${i}): expected ${expectedFileName} at ${expectedPosition}, got ${definition.fileName} at ${definition.textSpan.start}\n\n${text}\n`);
+                }
+                if (definition.unverified && (typeof endMarkerOrFileResult === "string" || !endMarkerOrFileResult.unverified)) {
+                    const isFileResult = typeof endMarkerOrFileResult !== "string" && !!endMarkerOrFileResult.file;
+                    this.raiseError(
+                        `${testName} failed for definition ${markerName || expectedFileName} (${i}): The actual definition was an \`unverified\` result. Use:\n\n` +
+                        `    verify.goToDefinition(${startMarker === undefined ? "startMarker" : `"${startMarker}"`}, { ${isFileResult ? `file: "${expectedFileName}"` : `marker: "${markerName}"`}, unverified: true })\n\n` +
+                        `if this is expected.`
+                    );
                 }
             });
         }
diff --git a/src/server/protocol.ts b/src/server/protocol.ts
index ffcde781d85c5..4608601f75ab0 100644
--- a/src/server/protocol.ts
+++ b/src/server/protocol.ts
@@ -1013,7 +1013,7 @@ namespace ts.server.protocol {
      * Definition response message.  Gives text range for definition.
      */
     export interface DefinitionResponse extends Response {
-        body?: FileSpanWithContext[];
+        body?: DefinitionInfo[];
     }
 
     export interface DefinitionInfoAndBoundSpanResponse extends Response {
diff --git a/src/server/session.ts b/src/server/session.ts
index e1f92187b3d49..c31002b94a626 100644
--- a/src/server/session.ts
+++ b/src/server/session.ts
@@ -1224,6 +1224,7 @@ namespace ts.server {
                     containerName: info.containerName,
                     kind: info.kind,
                     name: info.name,
+                    ...info.unverified && { unverified: info.unverified },
                 };
             });
         }
@@ -1300,8 +1301,8 @@ namespace ts.server {
             }));
         }
 
-        private mapDefinitionInfo(definitions: readonly DefinitionInfo[], project: Project): readonly protocol.FileSpanWithContext[] {
-            return definitions.map(def => this.toFileSpanWithContext(def.fileName, def.textSpan, def.contextSpan, project));
+        private mapDefinitionInfo(definitions: readonly DefinitionInfo[], project: Project): readonly protocol.DefinitionInfo[] {
+            return definitions.map(def => ({ ...this.toFileSpanWithContext(def.fileName, def.textSpan, def.contextSpan, project), ...def.unverified && { unverified: def.unverified } }));
         }
 
         /*
diff --git a/src/services/goToDefinition.ts b/src/services/goToDefinition.ts
index b77b8ed0a4ceb..76006e0d53f95 100644
--- a/src/services/goToDefinition.ts
+++ b/src/services/goToDefinition.ts
@@ -146,7 +146,7 @@ namespace ts.GoToDefinition {
                         end: node.getEnd(),
                         fileName: node.text
                     },
-                    unverified: !!verifiedFileName,
+                    unverified: !verifiedFileName,
                 };
             }
         }
diff --git a/src/testRunner/unittests/tsserver/partialSemanticServer.ts b/src/testRunner/unittests/tsserver/partialSemanticServer.ts
index edede23aee3b0..755570abc3101 100644
--- a/src/testRunner/unittests/tsserver/partialSemanticServer.ts
+++ b/src/testRunner/unittests/tsserver/partialSemanticServer.ts
@@ -218,7 +218,7 @@ function fooB() { }`
             assert.deepEqual(response.definitions, [{
                 file: file2.path,
                 start: { line: 1, offset: 1 },
-                end: { line: 1, offset: 1 }
+                end: { line: 1, offset: 1 },
             }]);
         });
     });
diff --git a/src/testRunner/unittests/tsserver/projectReferencesSourcemap.ts b/src/testRunner/unittests/tsserver/projectReferencesSourcemap.ts
index 21c72eec41bd7..d50f879a60dc5 100644
--- a/src/testRunner/unittests/tsserver/projectReferencesSourcemap.ts
+++ b/src/testRunner/unittests/tsserver/projectReferencesSourcemap.ts
@@ -4436,4 +4436,4 @@ ${dependencyTs.content}`);
             });
         });
     });
-}
\ No newline at end of file
+}
diff --git a/tests/baselines/reference/api/tsserverlibrary.d.ts b/tests/baselines/reference/api/tsserverlibrary.d.ts
index a2ff8fc1ea29a..3388024bff1c8 100644
--- a/tests/baselines/reference/api/tsserverlibrary.d.ts
+++ b/tests/baselines/reference/api/tsserverlibrary.d.ts
@@ -7389,7 +7389,7 @@ declare namespace ts.server.protocol {
      * Definition response message.  Gives text range for definition.
      */
     interface DefinitionResponse extends Response {
-        body?: FileSpanWithContext[];
+        body?: DefinitionInfo[];
     }
     interface DefinitionInfoAndBoundSpanResponse extends Response {
         body?: DefinitionInfoAndBoundSpan;
diff --git a/tests/cases/fourslash/fourslash.ts b/tests/cases/fourslash/fourslash.ts
index d1bc7f429c28d..295ba1fd14264 100644
--- a/tests/cases/fourslash/fourslash.ts
+++ b/tests/cases/fourslash/fourslash.ts
@@ -286,8 +286,8 @@ declare namespace FourSlashInterface {
          * `verify.goToDefinition(["a", "aa"], "b");` verifies that markers "a" and "aa" have the same definition "b".
          * `verify.goToDefinition("a", ["b", "bb"]);` verifies that "a" has multiple definitions available.
          */
-        goToDefinition(startMarkerNames: ArrayOrSingle<string>, fileResult: { file: string }): void;
-        goToDefinition(startMarkerNames: ArrayOrSingle<string>, endMarkerNames: ArrayOrSingle<string>): void;
+        goToDefinition(startMarkerNames: ArrayOrSingle<string>, fileResult: { file: string, unverified?: boolean }): void;
+        goToDefinition(startMarkerNames: ArrayOrSingle<string>, endMarkerNames: ArrayOrSingle<string | { marker: string, unverified?: boolean }>): void;
         goToDefinition(startMarkerNames: ArrayOrSingle<string>, endMarkerNames: ArrayOrSingle<string>, range: Range): void;
         /** Performs `goToDefinition` for each pair. */
         goToDefinition(startsAndEnds: [ArrayOrSingle<string>, ArrayOrSingle<string>][]): void;
diff --git a/tests/cases/fourslash/goToDefinitionCSSPatternAmbientModule.ts b/tests/cases/fourslash/goToDefinitionCSSPatternAmbientModule.ts
index 9d595e81eb444..16a53b7501ff0 100644
--- a/tests/cases/fourslash/goToDefinitionCSSPatternAmbientModule.ts
+++ b/tests/cases/fourslash/goToDefinitionCSSPatternAmbientModule.ts
@@ -14,4 +14,4 @@
 // @Filename: index.ts
 //// import styles from [|/*1*/"./index.css"|];
 
-verify.goToDefinition("1", ["2a", "2b"]);
+verify.goToDefinition("1", [{ marker: "2a", unverified: true }, "2b"]);
diff --git a/tests/cases/fourslash/goToDefinitionScriptImport.ts b/tests/cases/fourslash/goToDefinitionScriptImport.ts
index d576f5454ad30..5cede98c02a99 100644
--- a/tests/cases/fourslash/goToDefinitionScriptImport.ts
+++ b/tests/cases/fourslash/goToDefinitionScriptImport.ts
@@ -16,5 +16,5 @@
 // not JS/TS, but if we can, you should be able to jump to it.
 //// import [|/*2*/"./stylez.css"|];
 
-verify.goToDefinition("1", "1d");
-verify.goToDefinition("2", "2d");
+verify.goToDefinition("1", { marker: "1d", unverified: true });
+verify.goToDefinition("2", { marker: "2d", unverified: true });
diff --git a/tests/cases/fourslash/server/goToDefinitionScriptImportServer.ts b/tests/cases/fourslash/server/goToDefinitionScriptImportServer.ts
index 82e1e6ef5cea4..4d781c004d34e 100644
--- a/tests/cases/fourslash/server/goToDefinitionScriptImportServer.ts
+++ b/tests/cases/fourslash/server/goToDefinitionScriptImportServer.ts
@@ -19,6 +19,6 @@
 // does not exist, but should return a response to it anyway so an editor can create it.
 //// import [|/*3*/"./foo.txt"|];
 
-verify.goToDefinition("1", "1d");
-verify.goToDefinition("2", "2d");
-verify.goToDefinition("3", { file: "/foo.txt" });
+verify.goToDefinition("1", { marker: "1d", unverified: true });
+verify.goToDefinition("2", { marker: "2d", unverified: true });
+verify.goToDefinition("3", { file: "/foo.txt", unverified: true });