diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 26b93b19335..f2f6ad93562 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -2255,7 +2255,7 @@ namespace ts {
                         ? Diagnostics.If_the_0_package_actually_exposes_this_module_consider_sending_a_pull_request_to_amend_https_Colon_Slash_Slashgithub_com_SlashDefinitelyTyped_SlashDefinitelyTyped_Slashtree_Slashmaster_Slashtypes_Slash_1
                         : Diagnostics.Try_npm_install_types_Slash_1_if_it_exists_or_add_a_new_declaration_d_ts_file_containing_declare_module_0,
                     packageId.name,
-                    getMangledNameForScopedPackage(packageId.name))
+                    mangleScopedPackageName(packageId.name))
                 : undefined;
             errorOrSuggestion(isError, errorNode, chainDiagnosticMessages(
                 errorInfo,
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 6000c48de4d..ed528e5b87e 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -3273,7 +3273,7 @@
         "category": "Message",
         "code": 6104
     },
-    "Expected type of '{0}' field in 'package.json' to be 'string', got '{1}'.": {
+    "Expected type of '{0}' field in 'package.json' to be '{1}', got '{2}'.": {
         "category": "Message",
         "code": 6105
     },
diff --git a/src/compiler/moduleNameResolver.ts b/src/compiler/moduleNameResolver.ts
index 7fb308912c3..d1054579e84 100644
--- a/src/compiler/moduleNameResolver.ts
+++ b/src/compiler/moduleNameResolver.ts
@@ -88,6 +88,7 @@ namespace ts {
     interface PackageJsonPathFields {
         typings?: string;
         types?: string;
+        typesVersions?: MapLike<string>;
         main?: string;
     }
 
@@ -111,7 +112,7 @@ namespace ts {
             const fileName = jsonContent[fieldName];
             if (!isString(fileName)) {
                 if (state.traceEnabled) {
-                    trace(state.host, Diagnostics.Expected_type_of_0_field_in_package_json_to_be_string_got_1, fieldName, typeof fileName);
+                    trace(state.host, Diagnostics.Expected_type_of_0_field_in_package_json_to_be_1_got_2, fieldName, "string", typeof fileName);
                 }
                 return;
             }
@@ -124,21 +125,65 @@ namespace ts {
         }
     }
 
-    /* @internal */
-    export function readJson(path: string, host: { readFile(fileName: string): string | undefined }): object {
-        try {
-            const jsonText = host.readFile(path);
-            if (!jsonText) return {};
-            const result = parseConfigFileTextToJson(path, jsonText);
-            if (result.error) {
-                return {};
+    function tryReadPackageJsonTypesVersion(jsonContent: PackageJson, baseDirectory: string, state: ModuleResolutionState): string | undefined {
+        if (!hasProperty(jsonContent, "typesVersions")) {
+            if (state.traceEnabled) {
+                trace(state.host, Diagnostics.package_json_does_not_have_a_0_field, "typesVersions");
             }
-            return result.config;
+            return;
         }
-        catch (e) {
-            // gracefully handle if readFile fails or returns not JSON
-            return {};
+
+        const typesVersions = jsonContent.typesVersions;
+        if (typeof typesVersions !== "object") {
+            if (state.traceEnabled) {
+                trace(state.host, Diagnostics.Expected_type_of_0_field_in_package_json_to_be_1_got_2, "typesVersions", "object", typeof typesVersions);
+            }
+            return;
         }
+
+        const typeScriptVersion = Version.parse(version);
+        let bestVersion: Version | undefined;
+        let bestVersionKey: string | undefined;
+        for (const key in typesVersions) {
+            if (!hasProperty(typesVersions, key)) continue;
+
+            const keyVersion = Version.tryParse(key);
+            if (keyVersion === undefined) {
+                if (state.traceEnabled) {
+                    // TODO(rbuckton): log
+                }
+                continue;
+            }
+
+            // match the greatest version less than the current TypeScript version
+            if (keyVersion.compareTo(typeScriptVersion) <= 0
+                && (bestVersion === undefined || keyVersion.compareTo(bestVersion) > 0)) {
+                bestVersion = keyVersion;
+                bestVersionKey = key;
+            }
+        }
+
+        if (!bestVersionKey) {
+            if (state.traceEnabled) {
+                // TODO(rbuckton): log
+            }
+            return;
+        }
+
+        const bestVersionPath = typesVersions[bestVersionKey];
+        if (!isString(bestVersionPath)) {
+            if (state.traceEnabled) {
+                trace(state.host, Diagnostics.Expected_type_of_0_field_in_package_json_to_be_1_got_2, `typesVersion['${bestVersionKey}']`, "string", typeof bestVersionPath);
+            }
+            return;
+        }
+
+        if (state.traceEnabled) {
+            const path = normalizePath(combinePaths(baseDirectory, bestVersionPath));
+            trace(state.host, Diagnostics.package_json_has_0_field_1_that_references_2, `typesVersion['${bestVersionKey}']`, bestVersionPath, path);
+        }
+
+        return bestVersionPath;
     }
 
     export function getEffectiveTypeRoots(options: CompilerOptions, host: GetEffectiveTypeRootsHost): string[] | undefined {
@@ -720,7 +765,6 @@ namespace ts {
         }
         else {
             const candidate = normalizePath(combinePaths(state.compilerOptions.baseUrl, moduleName));
-
             if (state.traceEnabled) {
                 trace(state.host, Diagnostics.Resolving_module_name_0_relative_to_base_url_1_2, moduleName, state.compilerOptions.baseUrl, candidate);
             }
@@ -892,12 +936,6 @@ namespace ts {
         return path + "/index.d.ts";
     }
 
-    /* @internal */
-    export function directoryProbablyExists(directoryName: string, host: { directoryExists?: (directoryName: string) => boolean }): boolean {
-        // if host does not support 'directoryExists' assume that directory will exist
-        return !host.directoryExists || host.directoryExists(directoryName);
-    }
-
     function loadModuleFromFileNoPackageId(extensions: Extensions, candidate: string, failedLookupLocations: Push<string>, onlyRecordFailures: boolean, state: ModuleResolutionState): Resolved | undefined {
         return noPackageId(loadModuleFromFile(extensions, candidate, failedLookupLocations, onlyRecordFailures, state));
     }
@@ -977,9 +1015,12 @@ namespace ts {
     }
 
     function loadNodeModuleFromDirectory(extensions: Extensions, candidate: string, failedLookupLocations: Push<string>, onlyRecordFailures: boolean, state: ModuleResolutionState, considerPackageJson = true) {
-        const { packageJsonContent, packageId } = considerPackageJson
+        const { packageJsonContent, packageId, versionPath } = considerPackageJson
             ? getPackageJsonInfo(candidate, "", failedLookupLocations, onlyRecordFailures, state)
-            : { packageJsonContent: undefined, packageId: undefined };
+            : { packageJsonContent: undefined, packageId: undefined, versionPath: undefined };
+        if (versionPath) {
+            candidate = normalizePath(combinePaths(candidate, versionPath));
+        }
         return withPackageId(packageId, loadNodeModuleFromDirectoryWorker(extensions, candidate, failedLookupLocations, onlyRecordFailures, state, packageJsonContent));
     }
 
@@ -998,16 +1039,18 @@ namespace ts {
         failedLookupLocations: Push<string>,
         onlyRecordFailures: boolean,
         state: ModuleResolutionState,
-    ): { found: boolean, packageJsonContent: PackageJsonPathFields | undefined, packageId: PackageId | undefined } {
+    ): { found: boolean, packageJsonContent: PackageJsonPathFields | undefined, packageId: PackageId | undefined, versionPath: string | undefined } {
         const { host, traceEnabled } = state;
         const directoryExists = !onlyRecordFailures && directoryProbablyExists(nodeModuleDirectory, host);
         const packageJsonPath = pathToPackageJson(nodeModuleDirectory);
         if (directoryExists && host.fileExists(packageJsonPath)) {
             const packageJsonContent = readJson(packageJsonPath, host) as PackageJson;
+            const versionPath = tryReadPackageJsonTypesVersion(packageJsonContent, nodeModuleDirectory, state);
             if (subModuleName === "") { // looking up the root - need to handle types/typings/main redirects for subModuleName
-                const path = tryReadPackageJsonFields(/*readTypes*/ true, packageJsonContent, nodeModuleDirectory, state);
+                const versionDirectory = versionPath ? normalizePath(combinePaths(nodeModuleDirectory, versionPath)) : nodeModuleDirectory;
+                const path = tryReadPackageJsonFields(/*readTypes*/ true, packageJsonContent, versionDirectory, state);
                 if (typeof path === "string") {
-                    subModuleName = addExtensionAndIndex(path.substring(nodeModuleDirectory.length + 1));
+                    subModuleName = addExtensionAndIndex(path.substring(versionDirectory.length + 1));
                 }
                 else {
                     const jsPath = tryReadPackageJsonFields(/*readTypes*/ false, packageJsonContent, nodeModuleDirectory, state);
@@ -1021,6 +1064,11 @@ namespace ts {
                     }
                 }
             }
+
+            // if (versionPath) {
+            //     subModuleName = combinePaths(versionPath, subModuleName);
+            // }
+
             if (!endsWith(subModuleName, Extension.Dts)) {
                 subModuleName = addExtensionAndIndex(subModuleName);
             }
@@ -1035,15 +1083,16 @@ namespace ts {
                     trace(host, Diagnostics.Found_package_json_at_0, packageJsonPath);
                 }
             }
-            return { found: true, packageJsonContent, packageId };
+            return { found: true, packageJsonContent, packageId, versionPath };
         }
         else {
             if (directoryExists && traceEnabled) {
                 trace(host, Diagnostics.File_0_does_not_exist, packageJsonPath);
             }
+
             // record package json as one of failed lookup locations - in the future if this file will appear it will invalidate resolution results
             failedLookupLocations.push(packageJsonPath);
-            return { found: false, packageJsonContent: undefined, packageId: undefined };
+            return { found: false, packageJsonContent: undefined, packageId: undefined, versionPath: undefined };
         }
     }
 
@@ -1110,20 +1159,30 @@ namespace ts {
     }
 
     function loadModuleFromNodeModulesFolder(extensions: Extensions, moduleName: string, nodeModulesFolder: string, nodeModulesFolderExists: boolean, failedLookupLocations: Push<string>, state: ModuleResolutionState): Resolved | undefined {
-        const candidate = normalizePath(combinePaths(nodeModulesFolder, moduleName));
+        let candidate = normalizePath(combinePaths(nodeModulesFolder, moduleName));
         // First look for a nested package.json, as in `node_modules/foo/bar/package.json`.
         let packageJsonContent: PackageJsonPathFields | undefined;
+        let versionPath: string | undefined;
         let packageId: PackageId | undefined;
         const packageInfo = getPackageJsonInfo(candidate, "", failedLookupLocations, /*onlyRecordFailures*/ !nodeModulesFolderExists, state);
         if (packageInfo.found) {
-            ({ packageJsonContent, packageId } = packageInfo);
+            ({ packageJsonContent, packageId, versionPath } = packageInfo);
+
+            // If package.json supplied a typescript-version prefix path, apply it to the candidate.
+            if (versionPath) {
+                candidate = normalizePath(combinePaths(candidate, versionPath));
+            }
         }
         else {
-            const { packageName, rest } = getPackageName(moduleName);
+            const { packageName, rest } = parsePackageName(moduleName);
             if (rest !== "") { // If "rest" is empty, we just did this search above.
                 const packageRootPath = combinePaths(nodeModulesFolder, packageName);
                 // Don't use a "types" or "main" from here because we're not loading the root, but a subdirectory -- just here for the packageId.
-                packageId = getPackageJsonInfo(packageRootPath, rest, failedLookupLocations, !nodeModulesFolderExists, state).packageId;
+                ({ packageId, versionPath } = getPackageJsonInfo(packageRootPath, rest, failedLookupLocations, !nodeModulesFolderExists, state));
+                // If package.json supplied a typescript-version prefix path, apply it to the candidate.
+                if (versionPath) {
+                    candidate = normalizePath(combinePaths(packageRootPath, versionPath, rest));
+                }
             }
         }
         const pathAndExtension = loadModuleFromFile(extensions, candidate, failedLookupLocations, !nodeModulesFolderExists, state) ||
@@ -1132,7 +1191,7 @@ namespace ts {
     }
 
     /* @internal */
-    export function getPackageName(moduleName: string): { packageName: string, rest: string } {
+    export function parsePackageName(moduleName: string): { packageName: string, rest: string } {
         let idx = moduleName.indexOf(directorySeparator);
         if (moduleName[0] === "@") {
             idx = moduleName.indexOf(directorySeparator, idx + 1);
@@ -1141,14 +1200,14 @@ namespace ts {
     }
 
     function loadModuleFromNodeModules(extensions: Extensions, moduleName: string, directory: string, failedLookupLocations: Push<string>, state: ModuleResolutionState, cache: NonRelativeModuleNameResolutionCache | undefined): SearchResult<Resolved> {
-        return loadModuleFromNodeModulesWorker(extensions, moduleName, directory, failedLookupLocations, state, /*typesOnly*/ false, cache);
+        return loadModuleFromNearestNodeModules(extensions, moduleName, directory, failedLookupLocations, state, /*typesOnly*/ false, cache);
     }
     function loadModuleFromNodeModulesAtTypes(moduleName: string, directory: string, failedLookupLocations: Push<string>, state: ModuleResolutionState): SearchResult<Resolved> {
         // Extensions parameter here doesn't actually matter, because typesOnly ensures we're just doing @types lookup, which is always DtsOnly.
-        return loadModuleFromNodeModulesWorker(Extensions.DtsOnly, moduleName, directory, failedLookupLocations, state, /*typesOnly*/ true, /*cache*/ undefined);
+        return loadModuleFromNearestNodeModules(Extensions.DtsOnly, moduleName, directory, failedLookupLocations, state, /*typesOnly*/ true, /*cache*/ undefined);
     }
 
-    function loadModuleFromNodeModulesWorker(extensions: Extensions, moduleName: string, directory: string, failedLookupLocations: Push<string>, state: ModuleResolutionState, typesOnly: boolean, cache: NonRelativeModuleNameResolutionCache | undefined): SearchResult<Resolved> {
+    function loadModuleFromNearestNodeModules(extensions: Extensions, moduleName: string, directory: string, failedLookupLocations: Push<string>, state: ModuleResolutionState, typesOnly: boolean, cache: NonRelativeModuleNameResolutionCache | undefined): SearchResult<Resolved> {
         const perModuleNameCache = cache && cache.getOrCreateCacheForModuleName(moduleName);
         return forEachAncestorDirectory(normalizeSlashes(directory), ancestorDirectory => {
             if (getBaseFileName(ancestorDirectory) !== "node_modules") {
@@ -1156,13 +1215,12 @@ namespace ts {
                 if (resolutionFromCache) {
                     return resolutionFromCache;
                 }
-                return toSearchResult(loadModuleFromNodeModulesOneLevel(extensions, moduleName, ancestorDirectory, failedLookupLocations, state, typesOnly));
+                return toSearchResult(loadModuleFromImmediateNodeModules(extensions, moduleName, ancestorDirectory, failedLookupLocations, state, typesOnly));
             }
         });
     }
 
-    /** Load a module from a single node_modules directory, but not from any ancestors' node_modules directories. */
-    function loadModuleFromNodeModulesOneLevel(extensions: Extensions, moduleName: string, directory: string, failedLookupLocations: Push<string>, state: ModuleResolutionState, typesOnly = false): Resolved | undefined {
+    function loadModuleFromImmediateNodeModules(extensions: Extensions, moduleName: string, directory: string, failedLookupLocations: Push<string>, state: ModuleResolutionState, typesOnly: boolean): Resolved | undefined {
         const nodeModulesFolder = combinePaths(directory, "node_modules");
         const nodeModulesFolderExists = directoryProbablyExists(nodeModulesFolder, state.host);
         if (!nodeModulesFolderExists && state.traceEnabled) {
@@ -1182,7 +1240,7 @@ namespace ts {
                 }
                 nodeModulesAtTypesExists = false;
             }
-            return loadModuleFromNodeModulesFolder(Extensions.DtsOnly, mangleScopedPackage(moduleName, state), nodeModulesAtTypes, nodeModulesAtTypesExists, failedLookupLocations, state);
+            return loadModuleFromNodeModulesFolder(Extensions.DtsOnly, mangleScopedPackageNameWithTrace(moduleName, state), nodeModulesAtTypes, nodeModulesAtTypesExists, failedLookupLocations, state);
         }
     }
 
@@ -1190,8 +1248,8 @@ namespace ts {
     const mangledScopedPackageSeparator = "__";
 
     /** For a scoped package, we must look in `@types/foo__bar` instead of `@types/@foo/bar`. */
-    function mangleScopedPackage(packageName: string, state: ModuleResolutionState): string {
-        const mangled = getMangledNameForScopedPackage(packageName);
+    function mangleScopedPackageNameWithTrace(packageName: string, state: ModuleResolutionState): string {
+        const mangled = mangleScopedPackageName(packageName);
         if (state.traceEnabled && mangled !== packageName) {
             trace(state.host, Diagnostics.Scoped_package_detected_looking_in_0, mangled);
         }
@@ -1200,11 +1258,11 @@ namespace ts {
 
     /* @internal */
     export function getTypesPackageName(packageName: string): string {
-        return `@types/${getMangledNameForScopedPackage(packageName)}`;
+        return `@types/${mangleScopedPackageName(packageName)}`;
     }
 
     /* @internal */
-    export function getMangledNameForScopedPackage(packageName: string): string {
+    export function mangleScopedPackageName(packageName: string): string {
         if (startsWith(packageName, "@")) {
             const replaceSlash = packageName.replace(directorySeparator, mangledScopedPackageSeparator);
             if (replaceSlash !== packageName) {
@@ -1215,16 +1273,16 @@ namespace ts {
     }
 
     /* @internal */
-    export function getPackageNameFromAtTypesDirectory(mangledName: string): string {
+    export function getPackageNameFromTypesPackageName(mangledName: string): string {
         const withoutAtTypePrefix = removePrefix(mangledName, "@types/");
         if (withoutAtTypePrefix !== mangledName) {
-            return getUnmangledNameForScopedPackage(withoutAtTypePrefix);
+            return unmangleScopedPackageName(withoutAtTypePrefix);
         }
         return mangledName;
     }
 
     /* @internal */
-    export function getUnmangledNameForScopedPackage(typesPackageName: string): string {
+    export function unmangleScopedPackageName(typesPackageName: string): string {
         return stringContains(typesPackageName, mangledScopedPackageSeparator) ?
             "@" + typesPackageName.replace(mangledScopedPackageSeparator, directorySeparator) :
             typesPackageName;
@@ -1295,7 +1353,7 @@ namespace ts {
         }
         const state: ModuleResolutionState = { compilerOptions, host, traceEnabled };
         const failedLookupLocations: string[] = [];
-        const resolved = loadModuleFromNodeModulesOneLevel(Extensions.DtsOnly, moduleName, globalCache, failedLookupLocations, state);
+        const resolved = loadModuleFromImmediateNodeModules(Extensions.DtsOnly, moduleName, globalCache, failedLookupLocations, state, /*typesOnly*/ false);
         return createResolvedModuleWithFailedLookupLocations(resolved, /*isExternalLibraryImport*/ true, failedLookupLocations);
     }
 
diff --git a/src/compiler/moduleSpecifiers.ts b/src/compiler/moduleSpecifiers.ts
index 8c695e10be2..696736048b1 100644
--- a/src/compiler/moduleSpecifiers.ts
+++ b/src/compiler/moduleSpecifiers.ts
@@ -326,7 +326,7 @@ namespace ts.moduleSpecifiers {
         // if node_modules folder is in this folder or any of its parent folders, no need to keep it.
         if (!startsWith(sourceDirectory, getCanonicalFileName(moduleSpecifier.substring(0, parts.topLevelNodeModulesIndex)))) return undefined;
         // If the module was found in @types, get the actual Node package name
-        return getPackageNameFromAtTypesDirectory(moduleSpecifier.substring(parts.topLevelPackageNameIndex + 1));
+        return getPackageNameFromTypesPackageName(moduleSpecifier.substring(parts.topLevelPackageNameIndex + 1));
 
         function getDirectoryOrExtensionlessFileName(path: string): string {
             // If the file is the main module, it can be imported by the package name
diff --git a/src/compiler/semver.ts b/src/compiler/semver.ts
new file mode 100644
index 00000000000..a3c4e90d37a
--- /dev/null
+++ b/src/compiler/semver.ts
@@ -0,0 +1,156 @@
+/* @internal */
+namespace ts {
+    // Per https://semver.org/#spec-item-2:
+    //
+    // > A normal version number MUST take the form X.Y.Z where X, Y, and Z are non-negative
+    // > integers, and MUST NOT contain leading zeroes. X is the major version, Y is the minor
+    // > version, and Z is the patch version. Each element MUST increase numerically.
+    //
+    // NOTE: We differ here in that we allow X and X.Y, with missing parts having the default
+    // value of `0`.
+    const versionRegExp = /^(0|[1-9]\d*)(?:\.(0|[1-9]\d*)(?:\.(0|[1-9]\d*)(?:-([a-z0-9-.]+))?(?:(\+[a-z0-9-.]+))?)?)?$/i;
+
+    // Per https://semver.org/#spec-item-9:
+    //
+    // > A pre-release version MAY be denoted by appending a hyphen and a series of dot separated
+    // > identifiers immediately following the patch version. Identifiers MUST comprise only ASCII
+    // > alphanumerics and hyphen [0-9A-Za-z-]. Identifiers MUST NOT be empty. Numeric identifiers
+    // > MUST NOT include leading zeroes.
+    const prereleaseRegExp = /^(?:0|[1-9]\d*|[a-z-][a-z0-9-]*)(?:\.(?:0|[1-9]\d*|[a-z-][a-z0-9-]*))*$/i;
+
+    // Per https://semver.org/#spec-item-10:
+    //
+    // > Build metadata MAY be denoted by appending a plus sign and a series of dot separated
+    // > identifiers immediately following the patch or pre-release version. Identifiers MUST
+    // > comprise only ASCII alphanumerics and hyphen [0-9A-Za-z-]. Identifiers MUST NOT be empty.
+    const buildRegExp = /^[a-z0-9-]+(?:\.[a-z0-9-]+)*$/i;
+
+    // Per https://semver.org/#spec-item-9:
+    //
+    // > Numeric identifiers MUST NOT include leading zeroes.
+    const numericIdentifierRegExp = /^(0|[1-9]\d*)$/;
+
+    /**
+     * Describes a precise semantic version number, per https://semver.org
+     */
+    export class Version {
+        static readonly zero = new Version(0);
+
+        readonly major: number;
+        readonly minor: number;
+        readonly patch: number;
+        readonly prerelease: ReadonlyArray<string>;
+        readonly build: ReadonlyArray<string>;
+
+        constructor(major: number, minor = 0, patch = 0, prerelease = "", build = "") {
+            Debug.assert(major >= 0, "Invalid argument: major");
+            Debug.assert(minor >= 0, "Invalid argument: minor");
+            Debug.assert(patch >= 0, "Invalid argument: patch");
+            Debug.assert(!prerelease || prereleaseRegExp.test(prerelease), "Invalid argument: prerelease");
+            Debug.assert(!build || buildRegExp.test(build), "Invalid argument: build");
+            this.major = major;
+            this.minor = minor;
+            this.patch = patch;
+            this.prerelease = prerelease === "" ? emptyArray : prerelease.split(".");
+            this.build = build === "" ? emptyArray : build.split(".");
+        }
+
+        static parse(text: string) {
+            return Debug.assertDefined(this.tryParse(text));
+        }
+
+        static tryParse(text: string) {
+            const match = versionRegExp.exec(text);
+            if (!match) return undefined;
+
+            const [, major, minor = 0, patch = 0, prerelease, build] = match;
+            if (prerelease && !prereleaseRegExp.test(prerelease)) return undefined;
+            if (build && !buildRegExp.test(build)) return undefined;
+            return new Version(+major, +minor, +patch, prerelease, build);
+        }
+
+        static compare(left: Version | undefined, right: Version | undefined, compareBuildMetadata?: boolean) {
+            // Per https://semver.org/#spec-item-11:
+            //
+            // > Precedence is determined by the first difference when comparing each of these
+            // > identifiers from left to right as follows: Major, minor, and patch versions are
+            // > always compared numerically.
+            //
+            // > When major, minor, and patch are equal, a pre-release version has lower
+            // > precedence than a normal version.
+            //
+            // Per https://semver.org/#spec-item-10:
+            //
+            // > Build metadata SHOULD be ignored when determining version precedence.
+            if (left === right) return Comparison.EqualTo;
+            if (left === undefined) return Comparison.LessThan;
+            if (right === undefined) return Comparison.GreaterThan;
+            return compareValues(left.major, right.major)
+                || compareValues(left.minor, right.minor)
+                || compareValues(left.patch, right.patch)
+                || compareVersionFragments(left.prerelease, right.prerelease, /*compareNumericIdentifiers*/ true)
+                || (compareBuildMetadata ? compareVersionFragments(left.build, right.build, /*compareNumericIdentifiers*/ false) : Comparison.EqualTo);
+        }
+
+        compareTo(other: Version, compareBuildMetadata?: boolean) {
+            return Version.compare(this, other, compareBuildMetadata);
+        }
+
+        toString() {
+            let result = `${this.major}.${this.minor}.${this.patch}`;
+            if (this.prerelease) result += `-${this.prerelease.join(".")}`;
+            if (this.build) result += `+${this.build.join(".")}`;
+            return result;
+        }
+    }
+
+    function compareVersionFragments(left: ReadonlyArray<string>, right: ReadonlyArray<string>, compareNumericIdentifiers: boolean) {
+        // Per https://semver.org/#spec-item-11:
+        //
+        // > When major, minor, and patch are equal, a pre-release version has lower precedence
+        // > than a normal version.
+        if (left === right) return Comparison.EqualTo;
+        if (left.length === 0) return right.length === 0 ? Comparison.EqualTo : Comparison.GreaterThan;
+        if (right.length === 0) return Comparison.LessThan;
+
+        // Per https://semver.org/#spec-item-11:
+        //
+        // > Precedence for two pre-release versions with the same major, minor, and patch version
+        // > MUST be determined by comparing each dot separated identifier from left to right until
+        // > a difference is found
+        const length = Math.min(left.length, right.length);
+        for (let i = 0; i < length; i++) {
+            const leftIdentifier = left[i];
+            const rightIdentifier = right[i];
+            if (leftIdentifier === rightIdentifier) continue;
+
+            const leftIsNumeric = compareNumericIdentifiers && numericIdentifierRegExp.test(leftIdentifier);
+            const rightIsNumeric = compareNumericIdentifiers && numericIdentifierRegExp.test(rightIdentifier);
+            if (leftIsNumeric || rightIsNumeric) {
+                // Per https://semver.org/#spec-item-11:
+                //
+                // > Numeric identifiers always have lower precedence than non-numeric identifiers.
+                if (leftIsNumeric !== rightIsNumeric) return leftIsNumeric ? Comparison.LessThan : Comparison.GreaterThan;
+
+                // Per https://semver.org/#spec-item-11:
+                //
+                // > identifiers consisting of only digits are compared numerically
+                const result = compareValues(+leftIdentifier, +rightIdentifier);
+                if (result) return result;
+            }
+            else {
+                // Per https://semver.org/#spec-item-11:
+                //
+                // > identifiers with letters or hyphens are compared lexically in ASCII sort order.
+                const result = compareStringsCaseSensitive(leftIdentifier, rightIdentifier);
+                if (result) return result;
+            }
+        }
+
+        // Per https://semver.org/#spec-item-11:
+        //
+        // > A larger set of pre-release fields has a higher precedence than a smaller set, if all
+        // > of the preceding identifiers are equal.
+        return compareValues(left.length, right.length);
+    }
+}
\ No newline at end of file
diff --git a/src/compiler/tsconfig.json b/src/compiler/tsconfig.json
index 20b97c1b778..2d3cbcf54fe 100644
--- a/src/compiler/tsconfig.json
+++ b/src/compiler/tsconfig.json
@@ -9,6 +9,7 @@
     "files": [
         "core.ts",
         "performance.ts",
+        "semver.ts",
 
         "types.ts",
         "sys.ts",
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index 33dfd2617c9..e7eb352da84 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -3940,6 +3940,27 @@ namespace ts {
         return getStringFromExpandedCharCodes(expandedCharCodes);
     }
 
+    export function readJson(path: string, host: { readFile(fileName: string): string | undefined }): object {
+        try {
+            const jsonText = host.readFile(path);
+            if (!jsonText) return {};
+            const result = parseConfigFileTextToJson(path, jsonText);
+            if (result.error) {
+                return {};
+            }
+            return result.config;
+        }
+        catch (e) {
+            // gracefully handle if readFile fails or returns not JSON
+            return {};
+        }
+    }
+
+    export function directoryProbablyExists(directoryName: string, host: { directoryExists?: (directoryName: string) => boolean }): boolean {
+        // if host does not support 'directoryExists' assume that directory will exist
+        return !host.directoryExists || host.directoryExists(directoryName);
+    }
+
     const carriageReturnLineFeed = "\r\n";
     const lineFeed = "\n";
     export function getNewLineCharacter(options: CompilerOptions | PrinterOptions, getNewLine?: () => string): string {
diff --git a/src/services/codefixes/fixCannotFindModule.ts b/src/services/codefixes/fixCannotFindModule.ts
index 68fa3a5c030..6822cae7911 100644
--- a/src/services/codefixes/fixCannotFindModule.ts
+++ b/src/services/codefixes/fixCannotFindModule.ts
@@ -29,7 +29,7 @@ namespace ts.codefix {
 
     function getTypesPackageNameToInstall(host: LanguageServiceHost, sourceFile: SourceFile, pos: number, diagCode: number): string | undefined {
         const moduleName = cast(getTokenAtPosition(sourceFile, pos), isStringLiteral).text;
-        const { packageName } = getPackageName(moduleName);
+        const { packageName } = parsePackageName(moduleName);
         return diagCode === errorCodeCannotFindModule
             ? (JsTyping.nodeCoreModules.has(packageName) ? "@types/node" : undefined)
             : (host.isKnownTypesPackageName!(packageName) ? getTypesPackageName(packageName) : undefined); // TODO: GH#18217
diff --git a/src/services/pathCompletions.ts b/src/services/pathCompletions.ts
index 8ab7cc315ad..3a546573db7 100644
--- a/src/services/pathCompletions.ts
+++ b/src/services/pathCompletions.ts
@@ -329,7 +329,7 @@ namespace ts.Completions.PathCompletions {
         const seen = createMap<true>();
         if (options.types) {
             for (const typesName of options.types) {
-                const moduleName = getUnmangledNameForScopedPackage(typesName);
+                const moduleName = unmangleScopedPackageName(typesName);
                 pushResult(moduleName);
             }
         }
@@ -363,7 +363,7 @@ namespace ts.Completions.PathCompletions {
                     for (let typeDirectory of directories) {
                         typeDirectory = normalizePath(typeDirectory);
                         const directoryName = getBaseFileName(typeDirectory);
-                        const moduleName = getUnmangledNameForScopedPackage(directoryName);
+                        const moduleName = unmangleScopedPackageName(directoryName);
                         pushResult(moduleName);
                     }
                 }
diff --git a/tests/baselines/reference/duplicatePackage_relativeImportWithinPackage.trace.json b/tests/baselines/reference/duplicatePackage_relativeImportWithinPackage.trace.json
index d75683d210f..dbf67e3802c 100644
--- a/tests/baselines/reference/duplicatePackage_relativeImportWithinPackage.trace.json
+++ b/tests/baselines/reference/duplicatePackage_relativeImportWithinPackage.trace.json
@@ -2,6 +2,7 @@
     "======== Resolving module 'foo/use' from '/index.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
     "Loading module 'foo/use' from 'node_modules' folder, target file type 'TypeScript'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "Found 'package.json' at '/node_modules/foo/package.json'. Package ID is 'foo/use/index.d.ts@1.2.3'.",
     "File '/node_modules/foo/use.ts' does not exist.",
     "File '/node_modules/foo/use.tsx' does not exist.",
@@ -26,11 +27,13 @@
     "File '/node_modules/foo/index.ts' does not exist.",
     "File '/node_modules/foo/index.tsx' does not exist.",
     "File '/node_modules/foo/index.d.ts' exist - use it as a name resolution result.",
+    "'package.json' does not have a 'typesVersions' field.",
     "Found 'package.json' at '/node_modules/foo/package.json'. Package ID is 'foo/index.d.ts@1.2.3'.",
     "======== Module name './index' was successfully resolved to '/node_modules/foo/index.d.ts'. ========",
     "======== Resolving module 'foo' from '/node_modules/a/index.d.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
     "Loading module 'foo' from 'node_modules' folder, target file type 'TypeScript'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' does not have a 'typings' field.",
     "'package.json' does not have a 'types' field.",
     "'package.json' does not have a 'main' field.",
diff --git a/tests/baselines/reference/duplicatePackage_relativeImportWithinPackage_scoped.trace.json b/tests/baselines/reference/duplicatePackage_relativeImportWithinPackage_scoped.trace.json
index 7b07ecd66e4..d3d3dfac064 100644
--- a/tests/baselines/reference/duplicatePackage_relativeImportWithinPackage_scoped.trace.json
+++ b/tests/baselines/reference/duplicatePackage_relativeImportWithinPackage_scoped.trace.json
@@ -2,6 +2,7 @@
     "======== Resolving module '@foo/bar/use' from '/index.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
     "Loading module '@foo/bar/use' from 'node_modules' folder, target file type 'TypeScript'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "Found 'package.json' at '/node_modules/@foo/bar/package.json'. Package ID is '@foo/bar/use/index.d.ts@1.2.3'.",
     "File '/node_modules/@foo/bar/use.ts' does not exist.",
     "File '/node_modules/@foo/bar/use.tsx' does not exist.",
@@ -26,11 +27,13 @@
     "File '/node_modules/@foo/bar/index.ts' does not exist.",
     "File '/node_modules/@foo/bar/index.tsx' does not exist.",
     "File '/node_modules/@foo/bar/index.d.ts' exist - use it as a name resolution result.",
+    "'package.json' does not have a 'typesVersions' field.",
     "Found 'package.json' at '/node_modules/@foo/bar/package.json'. Package ID is '@foo/bar/index.d.ts@1.2.3'.",
     "======== Module name './index' was successfully resolved to '/node_modules/@foo/bar/index.d.ts'. ========",
     "======== Resolving module '@foo/bar' from '/node_modules/a/index.d.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
     "Loading module '@foo/bar' from 'node_modules' folder, target file type 'TypeScript'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' does not have a 'typings' field.",
     "'package.json' does not have a 'types' field.",
     "'package.json' does not have a 'main' field.",
diff --git a/tests/baselines/reference/library-reference-10.trace.json b/tests/baselines/reference/library-reference-10.trace.json
index ad34c0b1dc3..d24bc21f283 100644
--- a/tests/baselines/reference/library-reference-10.trace.json
+++ b/tests/baselines/reference/library-reference-10.trace.json
@@ -1,6 +1,7 @@
 [
     "======== Resolving type reference directive 'jquery', containing file '/foo/consumer.ts', root directory './types'. ========",
     "Resolving with primary search path './types'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' has 'typings' field 'jquery.d.ts' that references 'types/jquery/jquery.d.ts'.",
     "Found 'package.json' at './types/jquery/package.json'.",
     "'package.json' has 'typings' field 'jquery.d.ts' that references 'types/jquery/jquery.d.ts'.",
@@ -9,6 +10,7 @@
     "======== Type reference directive 'jquery' was successfully resolved to '/foo/types/jquery/jquery.d.ts', primary: true. ========",
     "======== Resolving type reference directive 'jquery', containing file '/foo/__inferred type names__.ts', root directory './types'. ========",
     "Resolving with primary search path './types'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' has 'typings' field 'jquery.d.ts' that references 'types/jquery/jquery.d.ts'.",
     "Found 'package.json' at './types/jquery/package.json'.",
     "'package.json' has 'typings' field 'jquery.d.ts' that references 'types/jquery/jquery.d.ts'.",
diff --git a/tests/baselines/reference/library-reference-11.trace.json b/tests/baselines/reference/library-reference-11.trace.json
index be260b6bc6e..5b2d6695356 100644
--- a/tests/baselines/reference/library-reference-11.trace.json
+++ b/tests/baselines/reference/library-reference-11.trace.json
@@ -3,6 +3,7 @@
     "Root directory cannot be determined, skipping primary search paths.",
     "Looking up in 'node_modules' folder, initial location '/a/b'.",
     "Directory '/a/b/node_modules' does not exist, skipping all lookups in it.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' has 'typings' field 'jquery.d.ts' that references '/a/node_modules/jquery/jquery.d.ts'.",
     "Found 'package.json' at '/a/node_modules/jquery/package.json'.",
     "File '/a/node_modules/jquery.d.ts' does not exist.",
diff --git a/tests/baselines/reference/library-reference-12.trace.json b/tests/baselines/reference/library-reference-12.trace.json
index 26361703708..f6c1aef4811 100644
--- a/tests/baselines/reference/library-reference-12.trace.json
+++ b/tests/baselines/reference/library-reference-12.trace.json
@@ -3,6 +3,7 @@
     "Root directory cannot be determined, skipping primary search paths.",
     "Looking up in 'node_modules' folder, initial location '/a/b'.",
     "Directory '/a/b/node_modules' does not exist, skipping all lookups in it.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' does not have a 'typings' field.",
     "'package.json' has 'types' field 'dist/jquery.d.ts' that references '/a/node_modules/jquery/dist/jquery.d.ts'.",
     "Found 'package.json' at '/a/node_modules/jquery/package.json'.",
diff --git a/tests/baselines/reference/library-reference-2.trace.json b/tests/baselines/reference/library-reference-2.trace.json
index 649189fbbdd..baef46d8995 100644
--- a/tests/baselines/reference/library-reference-2.trace.json
+++ b/tests/baselines/reference/library-reference-2.trace.json
@@ -1,6 +1,7 @@
 [
     "======== Resolving type reference directive 'jquery', containing file '/consumer.ts', root directory '/types'. ========",
     "Resolving with primary search path '/types'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' does not have a 'typings' field.",
     "'package.json' has 'types' field 'jquery.d.ts' that references '/types/jquery/jquery.d.ts'.",
     "Found 'package.json' at '/types/jquery/package.json'.",
@@ -11,6 +12,7 @@
     "======== Type reference directive 'jquery' was successfully resolved to '/types/jquery/jquery.d.ts', primary: true. ========",
     "======== Resolving type reference directive 'jquery', containing file '/test/__inferred type names__.ts', root directory '/types'. ========",
     "Resolving with primary search path '/types'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' does not have a 'typings' field.",
     "'package.json' has 'types' field 'jquery.d.ts' that references '/types/jquery/jquery.d.ts'.",
     "Found 'package.json' at '/types/jquery/package.json'.",
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_unexpected.trace.json b/tests/baselines/reference/moduleResolutionWithExtensions_unexpected.trace.json
index 60cdab44a29..2f743d9e200 100644
--- a/tests/baselines/reference/moduleResolutionWithExtensions_unexpected.trace.json
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_unexpected.trace.json
@@ -2,6 +2,7 @@
     "======== Resolving module 'normalize.css' from '/a.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
     "Loading module 'normalize.css' from 'node_modules' folder, target file type 'TypeScript'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' does not have a 'typings' field.",
     "'package.json' does not have a 'types' field.",
     "'package.json' has 'main' field 'normalize.css' that references '/node_modules/normalize.css/normalize.css'.",
@@ -24,6 +25,7 @@
     "File '/node_modules/normalize.css/index.d.ts' does not exist.",
     "Directory '/node_modules/@types' does not exist, skipping all lookups in it.",
     "Loading module 'normalize.css' from 'node_modules' folder, target file type 'JavaScript'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' does not have a 'typings' field.",
     "'package.json' does not have a 'types' field.",
     "'package.json' has 'main' field 'normalize.css' that references '/node_modules/normalize.css/normalize.css'.",
diff --git a/tests/baselines/reference/moduleResolutionWithExtensions_unexpected2.trace.json b/tests/baselines/reference/moduleResolutionWithExtensions_unexpected2.trace.json
index bab6be18d39..06610253558 100644
--- a/tests/baselines/reference/moduleResolutionWithExtensions_unexpected2.trace.json
+++ b/tests/baselines/reference/moduleResolutionWithExtensions_unexpected2.trace.json
@@ -2,6 +2,7 @@
     "======== Resolving module 'foo' from '/a.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
     "Loading module 'foo' from 'node_modules' folder, target file type 'TypeScript'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' does not have a 'typings' field.",
     "'package.json' has 'types' field 'foo.js' that references '/node_modules/foo/foo.js'.",
     "Found 'package.json' at '/node_modules/foo/package.json'.",
@@ -26,6 +27,7 @@
     "File '/node_modules/foo/index.d.ts' does not exist.",
     "Directory '/node_modules/@types' does not exist, skipping all lookups in it.",
     "Loading module 'foo' from 'node_modules' folder, target file type 'JavaScript'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' does not have a 'typings' field.",
     "'package.json' has 'types' field 'foo.js' that references '/node_modules/foo/foo.js'.",
     "Found 'package.json' at '/node_modules/foo/package.json'.",
diff --git a/tests/baselines/reference/moduleResolution_packageJson_notAtPackageRoot.trace.json b/tests/baselines/reference/moduleResolution_packageJson_notAtPackageRoot.trace.json
index 3473f33c1f2..2a4a1e71a4a 100644
--- a/tests/baselines/reference/moduleResolution_packageJson_notAtPackageRoot.trace.json
+++ b/tests/baselines/reference/moduleResolution_packageJson_notAtPackageRoot.trace.json
@@ -2,6 +2,7 @@
     "======== Resolving module 'foo/bar' from '/a.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
     "Loading module 'foo/bar' from 'node_modules' folder, target file type 'TypeScript'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' does not have a 'typings' field.",
     "'package.json' has 'types' field 'types.d.ts' that references '/node_modules/foo/bar/types.d.ts'.",
     "Found 'package.json' at '/node_modules/foo/bar/package.json'.",
diff --git a/tests/baselines/reference/moduleResolution_packageJson_notAtPackageRoot_fakeScopedPackage.trace.json b/tests/baselines/reference/moduleResolution_packageJson_notAtPackageRoot_fakeScopedPackage.trace.json
index 07dc908b745..b54519397ab 100644
--- a/tests/baselines/reference/moduleResolution_packageJson_notAtPackageRoot_fakeScopedPackage.trace.json
+++ b/tests/baselines/reference/moduleResolution_packageJson_notAtPackageRoot_fakeScopedPackage.trace.json
@@ -2,6 +2,7 @@
     "======== Resolving module 'foo/@bar' from '/a.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
     "Loading module 'foo/@bar' from 'node_modules' folder, target file type 'TypeScript'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' does not have a 'typings' field.",
     "'package.json' has 'types' field 'types.d.ts' that references '/node_modules/foo/@bar/types.d.ts'.",
     "Found 'package.json' at '/node_modules/foo/@bar/package.json'.",
diff --git a/tests/baselines/reference/moduleResolution_packageJson_scopedPackage.trace.json b/tests/baselines/reference/moduleResolution_packageJson_scopedPackage.trace.json
index 77ea6a244c1..389bd892d2f 100644
--- a/tests/baselines/reference/moduleResolution_packageJson_scopedPackage.trace.json
+++ b/tests/baselines/reference/moduleResolution_packageJson_scopedPackage.trace.json
@@ -2,6 +2,7 @@
     "======== Resolving module '@foo/bar' from '/a.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
     "Loading module '@foo/bar' from 'node_modules' folder, target file type 'TypeScript'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' does not have a 'typings' field.",
     "'package.json' has 'types' field 'types.d.ts' that references '/node_modules/@foo/bar/types.d.ts'.",
     "Found 'package.json' at '/node_modules/@foo/bar/package.json'.",
diff --git a/tests/baselines/reference/moduleResolution_packageJson_yesAtPackageRoot.trace.json b/tests/baselines/reference/moduleResolution_packageJson_yesAtPackageRoot.trace.json
index 453f5c088a3..873805b8b57 100644
--- a/tests/baselines/reference/moduleResolution_packageJson_yesAtPackageRoot.trace.json
+++ b/tests/baselines/reference/moduleResolution_packageJson_yesAtPackageRoot.trace.json
@@ -3,6 +3,7 @@
     "Module resolution kind is not specified, using 'NodeJs'.",
     "Loading module 'foo/bar' from 'node_modules' folder, target file type 'TypeScript'.",
     "File '/node_modules/foo/bar/package.json' does not exist.",
+    "'package.json' does not have a 'typesVersions' field.",
     "Found 'package.json' at '/node_modules/foo/package.json'. Package ID is 'foo/bar/index.d.ts@1.2.3'.",
     "File '/node_modules/foo/bar.ts' does not exist.",
     "File '/node_modules/foo/bar.tsx' does not exist.",
@@ -13,6 +14,7 @@
     "Directory '/node_modules/@types' does not exist, skipping all lookups in it.",
     "Loading module 'foo/bar' from 'node_modules' folder, target file type 'JavaScript'.",
     "File '/node_modules/foo/bar/package.json' does not exist.",
+    "'package.json' does not have a 'typesVersions' field.",
     "Found 'package.json' at '/node_modules/foo/package.json'. Package ID is 'foo/bar/index.d.ts@1.2.3'.",
     "File '/node_modules/foo/bar.js' does not exist.",
     "File '/node_modules/foo/bar.jsx' does not exist.",
diff --git a/tests/baselines/reference/moduleResolution_packageJson_yesAtPackageRoot_fakeScopedPackage.trace.json b/tests/baselines/reference/moduleResolution_packageJson_yesAtPackageRoot_fakeScopedPackage.trace.json
index b84bac8993a..95beae1393e 100644
--- a/tests/baselines/reference/moduleResolution_packageJson_yesAtPackageRoot_fakeScopedPackage.trace.json
+++ b/tests/baselines/reference/moduleResolution_packageJson_yesAtPackageRoot_fakeScopedPackage.trace.json
@@ -3,6 +3,7 @@
     "Module resolution kind is not specified, using 'NodeJs'.",
     "Loading module 'foo/@bar' from 'node_modules' folder, target file type 'TypeScript'.",
     "File '/node_modules/foo/@bar/package.json' does not exist.",
+    "'package.json' does not have a 'typesVersions' field.",
     "Found 'package.json' at '/node_modules/foo/package.json'. Package ID is 'foo/@bar/index.d.ts@1.2.3'.",
     "File '/node_modules/foo/@bar.ts' does not exist.",
     "File '/node_modules/foo/@bar.tsx' does not exist.",
@@ -13,6 +14,7 @@
     "Directory '/node_modules/@types' does not exist, skipping all lookups in it.",
     "Loading module 'foo/@bar' from 'node_modules' folder, target file type 'JavaScript'.",
     "File '/node_modules/foo/@bar/package.json' does not exist.",
+    "'package.json' does not have a 'typesVersions' field.",
     "Found 'package.json' at '/node_modules/foo/package.json'. Package ID is 'foo/@bar/index.d.ts@1.2.3'.",
     "File '/node_modules/foo/@bar.js' does not exist.",
     "File '/node_modules/foo/@bar.jsx' does not exist.",
diff --git a/tests/baselines/reference/moduleResolution_packageJson_yesAtPackageRoot_mainFieldInSubDirectory.trace.json b/tests/baselines/reference/moduleResolution_packageJson_yesAtPackageRoot_mainFieldInSubDirectory.trace.json
index 849b65ee59f..84b7a4873c0 100644
--- a/tests/baselines/reference/moduleResolution_packageJson_yesAtPackageRoot_mainFieldInSubDirectory.trace.json
+++ b/tests/baselines/reference/moduleResolution_packageJson_yesAtPackageRoot_mainFieldInSubDirectory.trace.json
@@ -2,6 +2,7 @@
     "======== Resolving module 'foo' from '/index.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
     "Loading module 'foo' from 'node_modules' folder, target file type 'TypeScript'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' does not have a 'typings' field.",
     "'package.json' does not have a 'types' field.",
     "'package.json' has 'main' field 'src/index.js' that references '/node_modules/foo/src/index.js'.",
diff --git a/tests/baselines/reference/packageJsonMain.trace.json b/tests/baselines/reference/packageJsonMain.trace.json
index 06c8cff6643..583fc96774e 100644
--- a/tests/baselines/reference/packageJsonMain.trace.json
+++ b/tests/baselines/reference/packageJsonMain.trace.json
@@ -2,6 +2,7 @@
     "======== Resolving module 'foo' from '/a.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
     "Loading module 'foo' from 'node_modules' folder, target file type 'TypeScript'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' does not have a 'typings' field.",
     "'package.json' does not have a 'types' field.",
     "'package.json' has 'main' field 'oof' that references '/node_modules/foo/oof'.",
@@ -23,6 +24,7 @@
     "File '/node_modules/foo/index.d.ts' does not exist.",
     "Directory '/node_modules/@types' does not exist, skipping all lookups in it.",
     "Loading module 'foo' from 'node_modules' folder, target file type 'JavaScript'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' does not have a 'typings' field.",
     "'package.json' does not have a 'types' field.",
     "'package.json' has 'main' field 'oof' that references '/node_modules/foo/oof'.",
@@ -38,6 +40,7 @@
     "======== Resolving module 'bar' from '/a.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
     "Loading module 'bar' from 'node_modules' folder, target file type 'TypeScript'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' does not have a 'typings' field.",
     "'package.json' does not have a 'types' field.",
     "'package.json' has 'main' field 'rab.js' that references '/node_modules/bar/rab.js'.",
@@ -64,6 +67,7 @@
     "File '/node_modules/bar/index.d.ts' does not exist.",
     "Directory '/node_modules/@types' does not exist, skipping all lookups in it.",
     "Loading module 'bar' from 'node_modules' folder, target file type 'JavaScript'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' does not have a 'typings' field.",
     "'package.json' does not have a 'types' field.",
     "'package.json' has 'main' field 'rab.js' that references '/node_modules/bar/rab.js'.",
@@ -77,6 +81,7 @@
     "======== Resolving module 'baz' from '/a.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
     "Loading module 'baz' from 'node_modules' folder, target file type 'TypeScript'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' does not have a 'typings' field.",
     "'package.json' does not have a 'types' field.",
     "'package.json' has 'main' field 'zab' that references '/node_modules/baz/zab'.",
@@ -100,6 +105,7 @@
     "File '/node_modules/baz/index.d.ts' does not exist.",
     "Directory '/node_modules/@types' does not exist, skipping all lookups in it.",
     "Loading module 'baz' from 'node_modules' folder, target file type 'JavaScript'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' does not have a 'typings' field.",
     "'package.json' does not have a 'types' field.",
     "'package.json' has 'main' field 'zab' that references '/node_modules/baz/zab'.",
diff --git a/tests/baselines/reference/packageJsonMain_isNonRecursive.trace.json b/tests/baselines/reference/packageJsonMain_isNonRecursive.trace.json
index a2878a2a4fe..b7d26d0f852 100644
--- a/tests/baselines/reference/packageJsonMain_isNonRecursive.trace.json
+++ b/tests/baselines/reference/packageJsonMain_isNonRecursive.trace.json
@@ -2,6 +2,7 @@
     "======== Resolving module 'foo' from '/a.ts'. ========",
     "Module resolution kind is not specified, using 'NodeJs'.",
     "Loading module 'foo' from 'node_modules' folder, target file type 'TypeScript'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' does not have a 'typings' field.",
     "'package.json' does not have a 'types' field.",
     "'package.json' has 'main' field 'oof' that references '/node_modules/foo/oof'.",
@@ -25,6 +26,7 @@
     "File '/node_modules/foo/index.d.ts' does not exist.",
     "Directory '/node_modules/@types' does not exist, skipping all lookups in it.",
     "Loading module 'foo' from 'node_modules' folder, target file type 'JavaScript'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' does not have a 'typings' field.",
     "'package.json' does not have a 'types' field.",
     "'package.json' has 'main' field 'oof' that references '/node_modules/foo/oof'.",
diff --git a/tests/baselines/reference/typesVersions.ambientModules.js b/tests/baselines/reference/typesVersions.ambientModules.js
new file mode 100644
index 00000000000..c7f198b8467
--- /dev/null
+++ b/tests/baselines/reference/typesVersions.ambientModules.js
@@ -0,0 +1,43 @@
+//// [tests/cases/conformance/moduleResolution/typesVersions.ambientModules.ts] ////
+
+//// [package.json]
+{
+    "name": "ext",
+    "version": "1.0.0",
+    "types": "index",
+    "typesVersions": {
+        "3.0": "ts3.0"
+    }
+}
+
+//// [index.d.ts]
+declare module "ext" {
+    export const a = "default a";
+}
+declare module "ext/other" {
+    export const b = "default b";
+}
+
+//// [index.d.ts]
+declare module "ext" {
+    export const a = "ts3.0 a";
+}
+declare module "ext/other" {
+    export const b = "ts3.0 b";
+}
+
+//// [main.ts]
+import { a } from "ext";
+import { b } from "ext/other";
+
+const aa: "ts3.0 a" = a;
+const bb: "ts3.0 b" = b;
+
+
+//// [main.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+const ext_1 = require("ext");
+const other_1 = require("ext/other");
+const aa = ext_1.a;
+const bb = other_1.b;
diff --git a/tests/baselines/reference/typesVersions.ambientModules.symbols b/tests/baselines/reference/typesVersions.ambientModules.symbols
new file mode 100644
index 00000000000..d8a0ab0f2ca
--- /dev/null
+++ b/tests/baselines/reference/typesVersions.ambientModules.symbols
@@ -0,0 +1,29 @@
+=== tests/cases/conformance/moduleResolution/main.ts ===
+import { a } from "ext";
+>a : Symbol(a, Decl(main.ts, 0, 8))
+
+import { b } from "ext/other";
+>b : Symbol(b, Decl(main.ts, 1, 8))
+
+const aa: "ts3.0 a" = a;
+>aa : Symbol(aa, Decl(main.ts, 3, 5))
+>a : Symbol(a, Decl(main.ts, 0, 8))
+
+const bb: "ts3.0 b" = b;
+>bb : Symbol(bb, Decl(main.ts, 4, 5))
+>b : Symbol(b, Decl(main.ts, 1, 8))
+
+=== tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/index.d.ts ===
+declare module "ext" {
+>"ext" : Symbol("ext", Decl(index.d.ts, 0, 0))
+
+    export const a = "ts3.0 a";
+>a : Symbol(a, Decl(index.d.ts, 1, 16))
+}
+declare module "ext/other" {
+>"ext/other" : Symbol("ext/other", Decl(index.d.ts, 2, 1))
+
+    export const b = "ts3.0 b";
+>b : Symbol(b, Decl(index.d.ts, 4, 16))
+}
+
diff --git a/tests/baselines/reference/typesVersions.ambientModules.trace.json b/tests/baselines/reference/typesVersions.ambientModules.trace.json
new file mode 100644
index 00000000000..990834accc2
--- /dev/null
+++ b/tests/baselines/reference/typesVersions.ambientModules.trace.json
@@ -0,0 +1,46 @@
+[
+    "======== Resolving module 'ext' from 'tests/cases/conformance/moduleResolution/main.ts'. ========",
+    "Module resolution kind is not specified, using 'NodeJs'.",
+    "Loading module 'ext' from 'node_modules' folder, target file type 'TypeScript'.",
+    "'package.json' has 'typesVersion['3.0']' field 'ts3.0' that references 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0'.",
+    "'package.json' does not have a 'typings' field.",
+    "'package.json' has 'types' field 'index' that references 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/index'.",
+    "Found 'package.json' at 'tests/cases/conformance/moduleResolution/node_modules/ext/package.json'. Package ID is 'ext/ts3.0/index.d.ts@1.0.0'.",
+    "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0.ts' does not exist.",
+    "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0.tsx' does not exist.",
+    "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0.d.ts' does not exist.",
+    "'package.json' does not have a 'typings' field.",
+    "'package.json' has 'types' field 'index' that references 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/index'.",
+    "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/index' does not exist.",
+    "Loading module as file / folder, candidate module location 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/index', target file type 'TypeScript'.",
+    "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/index.ts' does not exist.",
+    "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/index.tsx' does not exist.",
+    "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/index.d.ts' exist - use it as a name resolution result.",
+    "Resolving real path for 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/index.d.ts', result 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/index.d.ts'.",
+    "======== Module name 'ext' was successfully resolved to 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/index.d.ts'. ========",
+    "======== Resolving module 'ext/other' from 'tests/cases/conformance/moduleResolution/main.ts'. ========",
+    "Module resolution kind is not specified, using 'NodeJs'.",
+    "Loading module 'ext/other' from 'node_modules' folder, target file type 'TypeScript'.",
+    "'package.json' has 'typesVersion['3.0']' field 'ts3.0' that references 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0'.",
+    "Found 'package.json' at 'tests/cases/conformance/moduleResolution/node_modules/ext/package.json'. Package ID is 'ext/ts3.0/other/index.d.ts@1.0.0'.",
+    "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/other.ts' does not exist.",
+    "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/other.tsx' does not exist.",
+    "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/other.d.ts' does not exist.",
+    "Directory 'tests/cases/conformance/moduleResolution/node_modules/@types' does not exist, skipping all lookups in it.",
+    "Directory 'tests/cases/conformance/node_modules' does not exist, skipping all lookups in it.",
+    "Directory 'tests/cases/node_modules' does not exist, skipping all lookups in it.",
+    "Directory 'tests/node_modules' does not exist, skipping all lookups in it.",
+    "Directory 'node_modules' does not exist, skipping all lookups in it.",
+    "Directory '/node_modules' does not exist, skipping all lookups in it.",
+    "Loading module 'ext/other' from 'node_modules' folder, target file type 'JavaScript'.",
+    "'package.json' has 'typesVersion['3.0']' field 'ts3.0' that references 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0'.",
+    "Found 'package.json' at 'tests/cases/conformance/moduleResolution/node_modules/ext/package.json'. Package ID is 'ext/ts3.0/other/index.d.ts@1.0.0'.",
+    "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/other.js' does not exist.",
+    "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/other.jsx' does not exist.",
+    "Directory 'tests/cases/conformance/node_modules' does not exist, skipping all lookups in it.",
+    "Directory 'tests/cases/node_modules' does not exist, skipping all lookups in it.",
+    "Directory 'tests/node_modules' does not exist, skipping all lookups in it.",
+    "Directory 'node_modules' does not exist, skipping all lookups in it.",
+    "Directory '/node_modules' does not exist, skipping all lookups in it.",
+    "======== Module name 'ext/other' was not resolved. ========"
+]
\ No newline at end of file
diff --git a/tests/baselines/reference/typesVersions.ambientModules.types b/tests/baselines/reference/typesVersions.ambientModules.types
new file mode 100644
index 00000000000..20cd4112ebe
--- /dev/null
+++ b/tests/baselines/reference/typesVersions.ambientModules.types
@@ -0,0 +1,31 @@
+=== tests/cases/conformance/moduleResolution/main.ts ===
+import { a } from "ext";
+>a : "ts3.0 a"
+
+import { b } from "ext/other";
+>b : "ts3.0 b"
+
+const aa: "ts3.0 a" = a;
+>aa : "ts3.0 a"
+>a : "ts3.0 a"
+
+const bb: "ts3.0 b" = b;
+>bb : "ts3.0 b"
+>b : "ts3.0 b"
+
+=== tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/index.d.ts ===
+declare module "ext" {
+>"ext" : typeof import("ext")
+
+    export const a = "ts3.0 a";
+>a : "ts3.0 a"
+>"ts3.0 a" : "ts3.0 a"
+}
+declare module "ext/other" {
+>"ext/other" : typeof import("ext/other")
+
+    export const b = "ts3.0 b";
+>b : "ts3.0 b"
+>"ts3.0 b" : "ts3.0 b"
+}
+
diff --git a/tests/baselines/reference/typesVersions.multiFile.js b/tests/baselines/reference/typesVersions.multiFile.js
new file mode 100644
index 00000000000..98a1331500b
--- /dev/null
+++ b/tests/baselines/reference/typesVersions.multiFile.js
@@ -0,0 +1,39 @@
+//// [tests/cases/conformance/moduleResolution/typesVersions.multiFile.ts] ////
+
+//// [package.json]
+{
+    "name": "ext",
+    "version": "1.0.0",
+    "types": "index",
+    "typesVersions": {
+        "3.0": "ts3.0"
+    }
+}
+
+//// [index.d.ts]
+export const a = "default a";
+
+//// [other.d.ts]
+export const b = "default b";
+
+//// [index.d.ts]
+export const a = "ts3.0 a";
+
+//// [other.d.ts]
+export const b = "ts3.0 b";
+
+//// [main.ts]
+import { a } from "ext";
+import { b } from "ext/other";
+
+const aa: "ts3.0 a" = a;
+const bb: "ts3.0 b" = b;
+
+
+//// [main.js]
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+const ext_1 = require("ext");
+const other_1 = require("ext/other");
+const aa = ext_1.a;
+const bb = other_1.b;
diff --git a/tests/baselines/reference/typesVersions.multiFile.symbols b/tests/baselines/reference/typesVersions.multiFile.symbols
new file mode 100644
index 00000000000..c79bb054609
--- /dev/null
+++ b/tests/baselines/reference/typesVersions.multiFile.symbols
@@ -0,0 +1,31 @@
+=== tests/cases/conformance/moduleResolution/node_modules/ext/index.d.ts ===
+export const a = "default a";
+>a : Symbol(a, Decl(index.d.ts, 0, 12))
+
+=== tests/cases/conformance/moduleResolution/node_modules/ext/other.d.ts ===
+export const b = "default b";
+>b : Symbol(b, Decl(other.d.ts, 0, 12))
+
+=== tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/index.d.ts ===
+export const a = "ts3.0 a";
+>a : Symbol(a, Decl(index.d.ts, 0, 12))
+
+=== tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/other.d.ts ===
+export const b = "ts3.0 b";
+>b : Symbol(b, Decl(other.d.ts, 0, 12))
+
+=== tests/cases/conformance/moduleResolution/main.ts ===
+import { a } from "ext";
+>a : Symbol(a, Decl(main.ts, 0, 8))
+
+import { b } from "ext/other";
+>b : Symbol(b, Decl(main.ts, 1, 8))
+
+const aa: "ts3.0 a" = a;
+>aa : Symbol(aa, Decl(main.ts, 3, 5))
+>a : Symbol(a, Decl(main.ts, 0, 8))
+
+const bb: "ts3.0 b" = b;
+>bb : Symbol(bb, Decl(main.ts, 4, 5))
+>b : Symbol(b, Decl(main.ts, 1, 8))
+
diff --git a/tests/baselines/reference/typesVersions.multiFile.trace.json b/tests/baselines/reference/typesVersions.multiFile.trace.json
new file mode 100644
index 00000000000..0ef02bb8a02
--- /dev/null
+++ b/tests/baselines/reference/typesVersions.multiFile.trace.json
@@ -0,0 +1,31 @@
+[
+    "======== Resolving module 'ext' from 'tests/cases/conformance/moduleResolution/main.ts'. ========",
+    "Module resolution kind is not specified, using 'NodeJs'.",
+    "Loading module 'ext' from 'node_modules' folder, target file type 'TypeScript'.",
+    "'package.json' has 'typesVersion['3.0']' field 'ts3.0' that references 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0'.",
+    "'package.json' does not have a 'typings' field.",
+    "'package.json' has 'types' field 'index' that references 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/index'.",
+    "Found 'package.json' at 'tests/cases/conformance/moduleResolution/node_modules/ext/package.json'. Package ID is 'ext/ts3.0/index.d.ts@1.0.0'.",
+    "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0.ts' does not exist.",
+    "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0.tsx' does not exist.",
+    "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0.d.ts' does not exist.",
+    "'package.json' does not have a 'typings' field.",
+    "'package.json' has 'types' field 'index' that references 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/index'.",
+    "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/index' does not exist.",
+    "Loading module as file / folder, candidate module location 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/index', target file type 'TypeScript'.",
+    "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/index.ts' does not exist.",
+    "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/index.tsx' does not exist.",
+    "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/index.d.ts' exist - use it as a name resolution result.",
+    "Resolving real path for 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/index.d.ts', result 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/index.d.ts'.",
+    "======== Module name 'ext' was successfully resolved to 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/index.d.ts'. ========",
+    "======== Resolving module 'ext/other' from 'tests/cases/conformance/moduleResolution/main.ts'. ========",
+    "Module resolution kind is not specified, using 'NodeJs'.",
+    "Loading module 'ext/other' from 'node_modules' folder, target file type 'TypeScript'.",
+    "'package.json' has 'typesVersion['3.0']' field 'ts3.0' that references 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0'.",
+    "Found 'package.json' at 'tests/cases/conformance/moduleResolution/node_modules/ext/package.json'. Package ID is 'ext/ts3.0/other/index.d.ts@1.0.0'.",
+    "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/other.ts' does not exist.",
+    "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/other.tsx' does not exist.",
+    "File 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/other.d.ts' exist - use it as a name resolution result.",
+    "Resolving real path for 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/other.d.ts', result 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/other.d.ts'.",
+    "======== Module name 'ext/other' was successfully resolved to 'tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/other.d.ts'. ========"
+]
\ No newline at end of file
diff --git a/tests/baselines/reference/typesVersions.multiFile.types b/tests/baselines/reference/typesVersions.multiFile.types
new file mode 100644
index 00000000000..c0634803d29
--- /dev/null
+++ b/tests/baselines/reference/typesVersions.multiFile.types
@@ -0,0 +1,35 @@
+=== tests/cases/conformance/moduleResolution/node_modules/ext/index.d.ts ===
+export const a = "default a";
+>a : "default a"
+>"default a" : "default a"
+
+=== tests/cases/conformance/moduleResolution/node_modules/ext/other.d.ts ===
+export const b = "default b";
+>b : "default b"
+>"default b" : "default b"
+
+=== tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/index.d.ts ===
+export const a = "ts3.0 a";
+>a : "ts3.0 a"
+>"ts3.0 a" : "ts3.0 a"
+
+=== tests/cases/conformance/moduleResolution/node_modules/ext/ts3.0/other.d.ts ===
+export const b = "ts3.0 b";
+>b : "ts3.0 b"
+>"ts3.0 b" : "ts3.0 b"
+
+=== tests/cases/conformance/moduleResolution/main.ts ===
+import { a } from "ext";
+>a : "ts3.0 a"
+
+import { b } from "ext/other";
+>b : "ts3.0 b"
+
+const aa: "ts3.0 a" = a;
+>aa : "ts3.0 a"
+>a : "ts3.0 a"
+
+const bb: "ts3.0 b" = b;
+>bb : "ts3.0 b"
+>b : "ts3.0 b"
+
diff --git a/tests/baselines/reference/typingsLookup4.trace.json b/tests/baselines/reference/typingsLookup4.trace.json
index 6cd025d099a..30d0122b8fd 100644
--- a/tests/baselines/reference/typingsLookup4.trace.json
+++ b/tests/baselines/reference/typingsLookup4.trace.json
@@ -5,6 +5,7 @@
     "File '/node_modules/jquery.ts' does not exist.",
     "File '/node_modules/jquery.tsx' does not exist.",
     "File '/node_modules/jquery.d.ts' does not exist.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' has 'typings' field 'jquery.d.ts' that references '/node_modules/@types/jquery/jquery.d.ts'.",
     "Found 'package.json' at '/node_modules/@types/jquery/package.json'.",
     "File '/node_modules/@types/jquery.d.ts' does not exist.",
@@ -18,6 +19,7 @@
     "File '/node_modules/kquery.ts' does not exist.",
     "File '/node_modules/kquery.tsx' does not exist.",
     "File '/node_modules/kquery.d.ts' does not exist.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' has 'typings' field 'kquery' that references '/node_modules/@types/kquery/kquery'.",
     "Found 'package.json' at '/node_modules/@types/kquery/package.json'.",
     "File '/node_modules/@types/kquery.d.ts' does not exist.",
@@ -35,6 +37,7 @@
     "File '/node_modules/lquery.ts' does not exist.",
     "File '/node_modules/lquery.tsx' does not exist.",
     "File '/node_modules/lquery.d.ts' does not exist.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' has 'typings' field 'lquery' that references '/node_modules/@types/lquery/lquery'.",
     "Found 'package.json' at '/node_modules/@types/lquery/package.json'.",
     "File '/node_modules/@types/lquery.d.ts' does not exist.",
@@ -50,6 +53,7 @@
     "File '/node_modules/mquery.ts' does not exist.",
     "File '/node_modules/mquery.tsx' does not exist.",
     "File '/node_modules/mquery.d.ts' does not exist.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' has 'typings' field 'mquery' that references '/node_modules/@types/mquery/mquery'.",
     "Found 'package.json' at '/node_modules/@types/mquery/package.json'.",
     "File '/node_modules/@types/mquery.d.ts' does not exist.",
@@ -65,6 +69,7 @@
     "======== Module name 'mquery' was successfully resolved to '/node_modules/@types/mquery/mquery/index.tsx'. ========",
     "======== Resolving type reference directive 'jquery', containing file '/__inferred type names__.ts', root directory '/node_modules/@types'. ========",
     "Resolving with primary search path '/node_modules/@types'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' has 'typings' field 'jquery.d.ts' that references '/node_modules/@types/jquery/jquery.d.ts'.",
     "Found 'package.json' at '/node_modules/@types/jquery/package.json'.",
     "'package.json' has 'typings' field 'jquery.d.ts' that references '/node_modules/@types/jquery/jquery.d.ts'.",
@@ -73,6 +78,7 @@
     "======== Type reference directive 'jquery' was successfully resolved to '/node_modules/@types/jquery/jquery.d.ts', primary: true. ========",
     "======== Resolving type reference directive 'kquery', containing file '/__inferred type names__.ts', root directory '/node_modules/@types'. ========",
     "Resolving with primary search path '/node_modules/@types'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' has 'typings' field 'kquery' that references '/node_modules/@types/kquery/kquery'.",
     "Found 'package.json' at '/node_modules/@types/kquery/package.json'.",
     "'package.json' has 'typings' field 'kquery' that references '/node_modules/@types/kquery/kquery'.",
@@ -85,6 +91,7 @@
     "======== Type reference directive 'kquery' was successfully resolved to '/node_modules/@types/kquery/kquery.d.ts', primary: true. ========",
     "======== Resolving type reference directive 'lquery', containing file '/__inferred type names__.ts', root directory '/node_modules/@types'. ========",
     "Resolving with primary search path '/node_modules/@types'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' has 'typings' field 'lquery' that references '/node_modules/@types/lquery/lquery'.",
     "Found 'package.json' at '/node_modules/@types/lquery/package.json'.",
     "'package.json' has 'typings' field 'lquery' that references '/node_modules/@types/lquery/lquery'.",
@@ -95,6 +102,7 @@
     "======== Type reference directive 'lquery' was successfully resolved to '/node_modules/@types/lquery/lquery.ts', primary: true. ========",
     "======== Resolving type reference directive 'mquery', containing file '/__inferred type names__.ts', root directory '/node_modules/@types'. ========",
     "Resolving with primary search path '/node_modules/@types'.",
+    "'package.json' does not have a 'typesVersions' field.",
     "'package.json' has 'typings' field 'mquery' that references '/node_modules/@types/mquery/mquery'.",
     "Found 'package.json' at '/node_modules/@types/mquery/package.json'.",
     "'package.json' has 'typings' field 'mquery' that references '/node_modules/@types/mquery/mquery'.",
diff --git a/tests/cases/conformance/moduleResolution/typesVersions.ambientModules.ts b/tests/cases/conformance/moduleResolution/typesVersions.ambientModules.ts
new file mode 100644
index 00000000000..781740d96d2
--- /dev/null
+++ b/tests/cases/conformance/moduleResolution/typesVersions.ambientModules.ts
@@ -0,0 +1,39 @@
+// @traceResolution: true
+// @target: esnext
+// @module: commonjs
+// @noImplicitReferences: true
+// @filename: node_modules/ext/package.json
+{
+    "name": "ext",
+    "version": "1.0.0",
+    "types": "index",
+    "typesVersions": {
+        "3.0": "ts3.0"
+    }
+}
+
+// @filename: node_modules/ext/index.d.ts
+declare module "ext" {
+    export const a = "default a";
+}
+declare module "ext/other" {
+    export const b = "default b";
+}
+
+// @filename: node_modules/ext/ts3.0/index.d.ts
+declare module "ext" {
+    export const a = "ts3.0 a";
+}
+declare module "ext/other" {
+    export const b = "ts3.0 b";
+}
+
+// @filename: main.ts
+import { a } from "ext";
+import { b } from "ext/other";
+
+const aa: "ts3.0 a" = a;
+const bb: "ts3.0 b" = b;
+
+// @filename: tsconfig.json
+{}
\ No newline at end of file
diff --git a/tests/cases/conformance/moduleResolution/typesVersions.multiFile.ts b/tests/cases/conformance/moduleResolution/typesVersions.multiFile.ts
new file mode 100644
index 00000000000..44cf98e45c6
--- /dev/null
+++ b/tests/cases/conformance/moduleResolution/typesVersions.multiFile.ts
@@ -0,0 +1,34 @@
+// @traceResolution: true
+// @target: esnext
+// @module: commonjs
+// @filename: node_modules/ext/package.json
+{
+    "name": "ext",
+    "version": "1.0.0",
+    "types": "index",
+    "typesVersions": {
+        "3.0": "ts3.0"
+    }
+}
+
+// @filename: node_modules/ext/index.d.ts
+export const a = "default a";
+
+// @filename: node_modules/ext/other.d.ts
+export const b = "default b";
+
+// @filename: node_modules/ext/ts3.0/index.d.ts
+export const a = "ts3.0 a";
+
+// @filename: node_modules/ext/ts3.0/other.d.ts
+export const b = "ts3.0 b";
+
+// @filename: main.ts
+import { a } from "ext";
+import { b } from "ext/other";
+
+const aa: "ts3.0 a" = a;
+const bb: "ts3.0 b" = b;
+
+// @filename: tsconfig.json
+{}
\ No newline at end of file