diff --git a/.babelrc.json b/.babelrc.json
index e7e59a32a2..d6bcc04649 100644
--- a/.babelrc.json
+++ b/.babelrc.json
@@ -1,4 +1,9 @@
 {
   "plugins": ["@babel/plugin-transform-flow-strip-types"],
-  "presets": [["@babel/preset-env", { "targets": { "node": "current" } }]]
+  "presets": [
+    [
+      "@babel/preset-env",
+      { "bugfixes": true, "targets": { "node": "current" } }
+    ]
+  ]
 }
diff --git a/src/type/validate.js b/src/type/validate.js
index 9de721adae..919e58248d 100644
--- a/src/type/validate.js
+++ b/src/type/validate.js
@@ -183,11 +183,7 @@ function validateDirectives(context: SchemaValidationContext): void {
       if (isRequiredArgument(arg) && arg.deprecationReason != null) {
         context.reportError(
           `Required argument @${directive.name}(${arg.name}:) cannot be deprecated.`,
-          [
-            getDeprecatedDirectiveNode(arg.astNode),
-            // istanbul ignore next (TODO need to write coverage tests)
-            arg.astNode?.type,
-          ],
+          [getDeprecatedDirectiveNode(arg.astNode), arg.astNode?.type],
         );
       }
     }
@@ -299,11 +295,7 @@ function validateFields(
       if (isRequiredArgument(arg) && arg.deprecationReason != null) {
         context.reportError(
           `Required argument ${type.name}.${field.name}(${argName}:) cannot be deprecated.`,
-          [
-            getDeprecatedDirectiveNode(arg.astNode),
-            // istanbul ignore next (TODO need to write coverage tests)
-            arg.astNode?.type,
-          ],
+          [getDeprecatedDirectiveNode(arg.astNode), arg.astNode?.type],
         );
       }
     }
@@ -376,12 +368,7 @@ function validateTypeImplementsInterface(
         `Interface field ${iface.name}.${fieldName} expects type ` +
           `${inspect(ifaceField.type)} but ${type.name}.${fieldName} ` +
           `is type ${inspect(typeField.type)}.`,
-        [
-          // istanbul ignore next (TODO need to write coverage tests)
-          ifaceField.astNode?.type,
-          // istanbul ignore next (TODO need to write coverage tests)
-          typeField.astNode?.type,
-        ],
+        [ifaceField.astNode?.type, typeField.astNode?.type],
       );
     }
 
diff --git a/src/utilities/__tests__/buildASTSchema-test.js b/src/utilities/__tests__/buildASTSchema-test.js
index 4e3ca524d6..828ffa1abf 100644
--- a/src/utilities/__tests__/buildASTSchema-test.js
+++ b/src/utilities/__tests__/buildASTSchema-test.js
@@ -51,7 +51,6 @@ function cycleSDL(sdl: string): string {
 }
 
 function expectASTNode(obj: ?{ +astNode: ?ASTNode, ... }) {
-  // istanbul ignore next (FIXME)
   invariant(obj?.astNode != null);
   return expect(print(obj.astNode));
 }
diff --git a/src/utilities/__tests__/extendSchema-test.js b/src/utilities/__tests__/extendSchema-test.js
index cd26bcaf7d..67703c07e2 100644
--- a/src/utilities/__tests__/extendSchema-test.js
+++ b/src/utilities/__tests__/extendSchema-test.js
@@ -43,7 +43,6 @@ function expectExtensionASTNodes(obj: {
 }
 
 function expectASTNode(obj: ?{ +astNode: ?ASTNode, ... }) {
-  // istanbul ignore next (FIXME)
   invariant(obj?.astNode != null);
   return expect(print(obj.astNode));
 }
diff --git a/src/utilities/__tests__/getOperationRootType-test.js b/src/utilities/__tests__/getOperationRootType-test.js
index 627b0efb86..d96864fea6 100644
--- a/src/utilities/__tests__/getOperationRootType-test.js
+++ b/src/utilities/__tests__/getOperationRootType-test.js
@@ -36,7 +36,7 @@ const subscriptionType = new GraphQLObjectType({
 
 function getOperationNode(doc: DocumentNode) {
   const operationNode = doc.definitions[0];
-  invariant(operationNode && operationNode.kind === Kind.OPERATION_DEFINITION);
+  invariant(operationNode.kind === Kind.OPERATION_DEFINITION);
   return operationNode;
 }
 
@@ -76,7 +76,7 @@ describe('getOperationRootType', () => {
     `);
 
     const schemaNode = doc.definitions[0];
-    invariant(schemaNode && schemaNode.kind === Kind.SCHEMA_DEFINITION);
+    invariant(schemaNode.kind === Kind.SCHEMA_DEFINITION);
     const [
       queryNode,
       mutationNode,