diff --git a/.pnp.js b/.pnp.js
index 234a9ff9..56ab87a6 100755
--- a/.pnp.js
+++ b/.pnp.js
@@ -255,7 +255,7 @@ function $$SETUP_STATE(hydrateRuntimeState, basePath) {
       ],
       [
         "typescript",
-        "patch:typescript@npm%3A3.8.3#builtin<compat/typescript>::version=3.8.3&hash=c79188"
+        "patch:typescript@npm%3A3.9.0-dev.20200415#builtin<compat/typescript>::version=3.9.0-dev.20200415&hash=c79188"
       ],
       [
         "yaml",
@@ -329,7 +329,7 @@ function $$SETUP_STATE(hydrateRuntimeState, basePath) {
             ["ts-toolbelt", "npm:6.4.2"],
             ["ts-type-guards", "npm:0.6.1"],
             ["typeorm", "npm:0.2.24"],
-            ["typescript", "patch:typescript@npm%3A3.8.3#builtin<compat/typescript>::version=3.8.3&hash=c79188"],
+            ["typescript", "patch:typescript@npm%3A3.9.0-dev.20200415#builtin<compat/typescript>::version=3.9.0-dev.20200415&hash=c79188"],
             ["yaml", "npm:1.8.3"],
             ["yargs-parser", "npm:18.1.2"]
           ],
@@ -1389,7 +1389,7 @@ function $$SETUP_STATE(hydrateRuntimeState, basePath) {
             ["lodash.flatmap", "npm:4.5.0"],
             ["semver", "npm:6.3.0"],
             ["tslib", "npm:1.11.1"],
-            ["typescript", "patch:typescript@npm%3A3.8.3#builtin<compat/typescript>::version=3.8.3&hash=c79188"]
+            ["typescript", "patch:typescript@npm%3A3.9.0-dev.20200415#builtin<compat/typescript>::version=3.9.0-dev.20200415&hash=c79188"]
           ],
           "packagePeers": [
             "@stryker-mutator/core",
@@ -1725,7 +1725,7 @@ function $$SETUP_STATE(hydrateRuntimeState, basePath) {
             ["functional-red-black-tree", "npm:1.0.1"],
             ["regexpp", "npm:3.1.0"],
             ["tsutils", "virtual:699d88d3efcfc8c3b8e8fdb7b09c3a57f78f0707631e38ba146a639ca7f81d65f1f79a6af9167f1bdd70e674fb8cfdd2ed7ef8c24f6c232ef610d7a70508c96c#npm:3.17.1"],
-            ["typescript", "patch:typescript@npm%3A3.8.3#builtin<compat/typescript>::version=3.8.3&hash=c79188"]
+            ["typescript", "patch:typescript@npm%3A3.9.0-dev.20200415#builtin<compat/typescript>::version=3.9.0-dev.20200415&hash=c79188"]
           ],
           "packagePeers": [
             "eslint",
@@ -1762,7 +1762,7 @@ function $$SETUP_STATE(hydrateRuntimeState, basePath) {
             ["@typescript-eslint/typescript-estree", "virtual:10218aec97e5aa7a0aadd2419bf3b5b9aa0f4994381f5d2c0f9d198eb96ecff474c707524a13e223af4cb0674c2488a531376813f1c250c8577278cc5e4eb82c#npm:2.28.0"],
             ["eslint", "npm:6.8.0"],
             ["eslint-visitor-keys", "npm:1.1.0"],
-            ["typescript", "patch:typescript@npm%3A3.8.3#builtin<compat/typescript>::version=3.8.3&hash=c79188"]
+            ["typescript", "patch:typescript@npm%3A3.9.0-dev.20200415#builtin<compat/typescript>::version=3.9.0-dev.20200415&hash=c79188"]
           ],
           "packagePeers": [
             "eslint",
@@ -1783,7 +1783,7 @@ function $$SETUP_STATE(hydrateRuntimeState, basePath) {
             ["lodash", "npm:4.17.15"],
             ["semver", "npm:6.3.0"],
             ["tsutils", "virtual:699d88d3efcfc8c3b8e8fdb7b09c3a57f78f0707631e38ba146a639ca7f81d65f1f79a6af9167f1bdd70e674fb8cfdd2ed7ef8c24f6c232ef610d7a70508c96c#npm:3.17.1"],
-            ["typescript", "patch:typescript@npm%3A3.8.3#builtin<compat/typescript>::version=3.8.3&hash=c79188"]
+            ["typescript", "patch:typescript@npm%3A3.9.0-dev.20200415#builtin<compat/typescript>::version=3.9.0-dev.20200415&hash=c79188"]
           ],
           "packagePeers": [
             "typescript"
@@ -8126,7 +8126,7 @@ function $$SETUP_STATE(hydrateRuntimeState, basePath) {
             ["ts-toolbelt", "npm:6.4.2"],
             ["ts-type-guards", "npm:0.6.1"],
             ["typeorm", "npm:0.2.24"],
-            ["typescript", "patch:typescript@npm%3A3.8.3#builtin<compat/typescript>::version=3.8.3&hash=c79188"],
+            ["typescript", "patch:typescript@npm%3A3.9.0-dev.20200415#builtin<compat/typescript>::version=3.9.0-dev.20200415&hash=c79188"],
             ["yaml", "npm:1.8.3"],
             ["yargs-parser", "npm:18.1.2"]
           ],
@@ -10690,7 +10690,7 @@ function $$SETUP_STATE(hydrateRuntimeState, basePath) {
             ["diff", "npm:4.0.2"],
             ["make-error", "npm:1.3.6"],
             ["source-map-support", "npm:0.5.16"],
-            ["typescript", "patch:typescript@npm%3A3.8.3#builtin<compat/typescript>::version=3.8.3&hash=c79188"],
+            ["typescript", "patch:typescript@npm%3A3.9.0-dev.20200415#builtin<compat/typescript>::version=3.9.0-dev.20200415&hash=c79188"],
             ["yn", "npm:3.1.1"]
           ],
           "packagePeers": [
@@ -10732,7 +10732,7 @@ function $$SETUP_STATE(hydrateRuntimeState, basePath) {
           "packageDependencies": [
             ["tsutils", "virtual:699d88d3efcfc8c3b8e8fdb7b09c3a57f78f0707631e38ba146a639ca7f81d65f1f79a6af9167f1bdd70e674fb8cfdd2ed7ef8c24f6c232ef610d7a70508c96c#npm:3.17.1"],
             ["tslib", "npm:1.11.1"],
-            ["typescript", "patch:typescript@npm%3A3.8.3#builtin<compat/typescript>::version=3.8.3&hash=c79188"]
+            ["typescript", "patch:typescript@npm%3A3.9.0-dev.20200415#builtin<compat/typescript>::version=3.9.0-dev.20200415&hash=c79188"]
           ],
           "packagePeers": [
             "typescript"
@@ -10885,6 +10885,13 @@ function $$SETUP_STATE(hydrateRuntimeState, basePath) {
             ["typescript", "patch:typescript@npm%3A3.8.3#builtin<compat/typescript>::version=3.8.3&hash=c79188"]
           ],
           "linkType": "HARD",
+        }],
+        ["patch:typescript@npm%3A3.9.0-dev.20200415#builtin<compat/typescript>::version=3.9.0-dev.20200415&hash=c79188", {
+          "packageLocation": "./.yarn/cache/typescript-patch-1c362703ff-2.zip/node_modules/typescript/",
+          "packageDependencies": [
+            ["typescript", "patch:typescript@npm%3A3.9.0-dev.20200415#builtin<compat/typescript>::version=3.9.0-dev.20200415&hash=c79188"]
+          ],
+          "linkType": "HARD",
         }]
       ]],
       ["underscore", [
diff --git a/.yarn/cache/typescript-npm-3.9.0-dev.20200415-2f8a315906-2.zip b/.yarn/cache/typescript-npm-3.9.0-dev.20200415-2f8a315906-2.zip
new file mode 100644
index 00000000..d6e9d4d2
Binary files /dev/null and b/.yarn/cache/typescript-npm-3.9.0-dev.20200415-2f8a315906-2.zip differ
diff --git a/.yarn/cache/typescript-patch-1c362703ff-2.zip b/.yarn/cache/typescript-patch-1c362703ff-2.zip
new file mode 100644
index 00000000..a52557c2
Binary files /dev/null and b/.yarn/cache/typescript-patch-1c362703ff-2.zip differ
diff --git a/package.json b/package.json
index 5f5e3886..d5d95df7 100644
--- a/package.json
+++ b/package.json
@@ -99,7 +99,7 @@
     "ts-jest": "~25.3.1",
     "ts-node": "~8.8.2",
     "ts-toolbelt": "~6.4.2",
-    "typescript": "~3.8.3"
+    "typescript": "next"
   },
   "dependencies": {
     "array-flat-polyfill": "~1.0.1",
diff --git a/test/common/testers/repositoryProviderTester.ts b/test/common/testers/repositoryProviderTester.ts
index 19b70fff..6ed6c8d9 100644
--- a/test/common/testers/repositoryProviderTester.ts
+++ b/test/common/testers/repositoryProviderTester.ts
@@ -14,6 +14,7 @@ export const testRepositoryProvider = <E extends IEntity, P extends IRepositoryP
   describe(`${Entity} repository provider`, () => {
     const repositoryMock = mock<Repository<E>>();
     const connectionMock = mock<Connection>();
+    // @ts-ignore
     connectionMock.getRepository.mockReturnValue(repositoryMock);
     const connectionProviderMock = mock<IConnectionProvider>();
     connectionProviderMock.getConnection.mockResolvedValue(connectionMock);
diff --git a/test/src/db/impl/connectionProvider.spec.ts b/test/src/db/impl/connectionProvider.spec.ts
index 5c4df509..198997eb 100644
--- a/test/src/db/impl/connectionProvider.spec.ts
+++ b/test/src/db/impl/connectionProvider.spec.ts
@@ -11,6 +11,7 @@ describe(`connection provider`, () => {
   let tmpDir: string;
   const connectionMock = mock<Connection>();
   const typeOrmMock = mock<TypeOrm>();
+  // @ts-ignore
   typeOrmMock.createConnection.mockResolvedValue(connectionMock);
 
   beforeEach(() => {
diff --git a/test/src/resolvers/cacheResolver/impl/cacheResolver.spec.ts b/test/src/resolvers/cacheResolver/impl/cacheResolver.spec.ts
index 488051bd..656b3d83 100644
--- a/test/src/resolvers/cacheResolver/impl/cacheResolver.spec.ts
+++ b/test/src/resolvers/cacheResolver/impl/cacheResolver.spec.ts
@@ -7,6 +7,7 @@ import { mock, mockReset } from 'jest-mock-extended';
 describe(`cache resolver`, () => {
   const repositoryMock = mock<Repository<Dependency>>();
   const dependencyRepositoryProviderMock = mock<IDependencyRepositoryProvider>();
+  // @ts-ignore
   dependencyRepositoryProviderMock.getRepository.mockResolvedValue(repositoryMock);
   const cacheResolver = new CacheResolver(dependencyRepositoryProviderMock, loggerFactory);
 
diff --git a/yarn.lock b/yarn.lock
index 1916518b..ff0dd693 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -7180,7 +7180,7 @@ fsevents@^2.1.2:
     ts-toolbelt: ~6.4.2
     ts-type-guards: ~0.6.1
     typeorm: ~0.2.24
-    typescript: ~3.8.3
+    typescript: next
     yaml: ~1.8.3
     yargs-parser: ~18.1.2
   bin:
@@ -9691,7 +9691,7 @@ resolve@1.1.7:
   languageName: node
   linkType: hard
 
-"typescript@^3.6.3, typescript@~3.8.3":
+typescript@^3.6.3:
   version: 3.8.3
   resolution: "typescript@npm:3.8.3"
   bin:
@@ -9701,7 +9701,17 @@ resolve@1.1.7:
   languageName: node
   linkType: hard
 
-"typescript@patch:typescript@^3.6.3#builtin<compat/typescript>, typescript@patch:typescript@~3.8.3#builtin<compat/typescript>":
+typescript@next:
+  version: 3.9.0-dev.20200415
+  resolution: "typescript@npm:3.9.0-dev.20200415"
+  bin:
+    tsc: bin/tsc
+    tsserver: bin/tsserver
+  checksum: 2/9973b0c706b38eee0ac2738fbdf871507751545a21be864b160344dbbb5860275c6ff75fd15cb1cf184d227dec81626182ebbd0de334721aafd22e4e5c706813
+  languageName: node
+  linkType: hard
+
+"typescript@patch:typescript@^3.6.3#builtin<compat/typescript>":
   version: 3.8.3
   resolution: "typescript@patch:typescript@npm%3A3.8.3#builtin<compat/typescript>::version=3.8.3&hash=c79188"
   bin:
@@ -9711,6 +9721,16 @@ resolve@1.1.7:
   languageName: node
   linkType: hard
 
+"typescript@patch:typescript@next#builtin<compat/typescript>":
+  version: 3.9.0-dev.20200415
+  resolution: "typescript@patch:typescript@npm%3A3.9.0-dev.20200415#builtin<compat/typescript>::version=3.9.0-dev.20200415&hash=c79188"
+  bin:
+    tsc: bin/tsc
+    tsserver: bin/tsserver
+  checksum: 2/027c594d74500a6fe66997c2d3ab3b9677509fc5d64c057233908054bd93cf5e1a7ef34560c2039d1b04c8273d0bc3fedb48d462397ccc816fe581501d1b6cbe
+  languageName: node
+  linkType: hard
+
 "underscore@npm:1.8.3":
   version: 1.8.3
   resolution: "underscore@npm:1.8.3"