diff --git a/src/compiler/sourcemapDecoder.ts b/src/compiler/sourcemapDecoder.ts
index 5dae6dbd3b7..b09b919e0e0 100644
--- a/src/compiler/sourcemapDecoder.ts
+++ b/src/compiler/sourcemapDecoder.ts
@@ -146,7 +146,7 @@ namespace ts.sourcemaps {
     }
 
     /*@internal*/
-    export function decodeMappings(map: RawSourceMap): MappingsDecoder {
+    export function decodeMappings(map: Pick<RawSourceMap, "mappings" | "sources" | "names">): MappingsDecoder {
         const state: DecoderState = {
             encodedText: map.mappings,
             currentNameIndex: undefined,
diff --git a/src/harness/sourceMapRecorder.ts b/src/harness/sourceMapRecorder.ts
index 78a71ba9fb6..65236e78cb7 100644
--- a/src/harness/sourceMapRecorder.ts
+++ b/src/harness/sourceMapRecorder.ts
@@ -19,11 +19,7 @@ namespace Harness.SourceMapRecorder {
             decodingIndex = 0;
             sourceMapMappings = sourceMapData.sourceMapMappings;
             mappings = ts.sourcemaps.decodeMappings({
-                version: 3,
-                file: sourceMapData.sourceMapFile,
                 sources: sourceMapData.sourceMapSources,
-                sourceRoot: sourceMapData.sourceMapSourceRoot,
-                sourcesContent: sourceMapData.sourceMapSourcesContent,
                 mappings: sourceMapData.sourceMapMappings,
                 names: sourceMapData.sourceMapNames
             });