From c4deeeee60446f8fe9ad32b3f59bfeb8df23b759 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <nathansa@microsoft.com>
Date: Mon, 2 Oct 2017 10:23:55 -0700
Subject: [PATCH] Strict function variance fixes round 1, stage 2

---
 types/knockout/index.d.ts    |   4 +-
 types/knockout/tsconfig.json |   3 +-
 types/lodash/index.d.ts      | 169 ++++++++++++++++++++++++++---------
 types/lodash/lodash-tests.ts | 146 +++++++++++++++---------------
 types/lodash/tsconfig.json   |   3 +-
 types/log4js/log4js-tests.ts |   4 +-
 types/log4js/tsconfig.json   |   3 +-
 types/node/node-tests.ts     |   4 +-
 8 files changed, 213 insertions(+), 123 deletions(-)

diff --git a/types/knockout/index.d.ts b/types/knockout/index.d.ts
index 3a206fd04c..4ef3bc8739 100644
--- a/types/knockout/index.d.ts
+++ b/types/knockout/index.d.ts
@@ -151,8 +151,8 @@ interface KnockoutAllBindingsAccessor {
 
 interface KnockoutBindingHandler {
     after?: Array<string>;
-    init?: (element: any, valueAccessor: () => any, allBindingsAccessor?: KnockoutAllBindingsAccessor, viewModel?: any, bindingContext?: KnockoutBindingContext) => void | { controlsDescendantBindings: boolean; };
-    update?: (element: any, valueAccessor: () => any, allBindingsAccessor?: KnockoutAllBindingsAccessor, viewModel?: any, bindingContext?: KnockoutBindingContext) => void;
+    init?: (element: any, valueAccessor: () => any, allBindingsAccessor: KnockoutAllBindingsAccessor, viewModel: any, bindingContext: KnockoutBindingContext) => void | { controlsDescendantBindings: boolean; };
+    update?: (element: any, valueAccessor: () => any, allBindingsAccessor: KnockoutAllBindingsAccessor, viewModel: any, bindingContext: KnockoutBindingContext) => void;
     options?: any;
     preprocess?: (value: string, name: string, addBindingCallback?: (name: string, value: string) => void) => string;
     [s: string]: any;
diff --git a/types/knockout/tsconfig.json b/types/knockout/tsconfig.json
index f6f1635804..9e76a7c908 100644
--- a/types/knockout/tsconfig.json
+++ b/types/knockout/tsconfig.json
@@ -8,6 +8,7 @@
         "noImplicitAny": false,
         "noImplicitThis": false,
         "strictNullChecks": true,
+        "strictFunctionTypes": true,
         "baseUrl": "../",
         "typeRoots": [
             "../"
@@ -21,4 +22,4 @@
         "test/templatingBehaviors.ts",
         "test/index.ts"
     ]
-}
\ No newline at end of file
+}
diff --git a/types/lodash/index.d.ts b/types/lodash/index.d.ts
index d487135799..58698cb4f3 100644
--- a/types/lodash/index.d.ts
+++ b/types/lodash/index.d.ts
@@ -4794,6 +4794,14 @@ declare namespace _ {
          * _.uniqBy([{ 'x': 1 }, { 'x': 2 }, { 'x': 1 }], 'x');
          * // => [{ 'x': 1 }, { 'x': 2 }]
          */
+        uniqBy<TString extends string | null | undefined>(
+            array: TString,
+            iteratee: StringIterator<any>
+        ): TString[];
+
+        /**
+         * @see _.uniqBy
+         */
         uniqBy<T>(
             array: List<T> | null | undefined,
             iteratee: ListIterator<T, any>
@@ -4832,6 +4840,24 @@ declare namespace _ {
         ): T[];
     }
 
+    interface LoDashImplicitStringWrapper {
+        /**
+         * @see _.uniqBy
+         */
+        uniqBy(
+            iteratee: StringIterator<any>
+        ): LoDashImplicitArrayWrapper<string>;
+    }
+
+    interface LoDashExplicitStringWrapper {
+        /**
+         * @see _.uniqBy
+         */
+        uniqBy(
+            iteratee: StringIterator<any>
+        ): LoDashExplicitArrayWrapper<string>;
+    }
+
     interface LoDashImplicitWrapper<T> {
         /**
          * @see _.uniqBy
@@ -5074,6 +5100,14 @@ declare namespace _ {
          * _.sortedUniqBy([1.1, 1.2, 2.3, 2.4], Math.floor);
          * // => [1.1, 2.2]
          */
+        sortedUniqBy<TString extends string | null | undefined>(
+            array: TString,
+            iteratee: StringIterator<any>
+        ): TString[];
+
+        /**
+         * @see _.sortedUniqBy
+         */
         sortedUniqBy<T>(
             array: List<T> | null | undefined,
             iteratee: ListIterator<T, any>
@@ -5112,6 +5146,24 @@ declare namespace _ {
         ): T[];
     }
 
+    interface LoDashImplicitStringWrapper {
+        /**
+         * @see _.sortedUniqBy
+         */
+        sortedUniqBy(
+            iteratee: StringIterator<any>
+        ): LoDashImplicitArrayWrapper<string>;
+    }
+
+    interface LoDashExplicitStringWrapper {
+        /**
+         * @see _.sortedUniqBy
+         */
+        sortedUniqBy(
+            iteratee: StringIterator<any>
+        ): LoDashExplicitArrayWrapper<string>;
+    }
+
     interface LoDashImplicitWrapper<T> {
         /**
          * @see _.sortedUniqBy
@@ -5823,6 +5875,13 @@ declare namespace _ {
         chain(value: any): LoDashExplicitWrapper<any>;
     }
 
+    interface LoDashImplicitStringWrapper {
+        /**
+         * @see _.chain
+         */
+        chain(): LoDashExplicitStringWrapper;
+    }
+
     interface LoDashImplicitWrapper<T> {
         /**
          * @see _.chain
@@ -7796,6 +7855,14 @@ declare namespace _ {
          * @param thisArg The this binding of iteratee.
          * @return Returns the composed aggregate object.
          */
+        groupBy<TString extends string | null | undefined, TKey>(
+            collection: TString,
+            iteratee?: StringIterator<TKey>
+        ): Dictionary<TString[]>;
+
+        /**
+         * @see _.groupBy
+         */
         groupBy<T, TKey>(
             collection: List<T> | null | undefined,
             iteratee?: ListIterator<T, TKey>
@@ -8165,6 +8232,24 @@ declare namespace _ {
         ): Dictionary<T>;
     }
 
+    interface LoDashImplicitStringWrapper {
+        /**
+         * @see _.keyBy
+         */
+        keyBy(
+            iteratee?: StringIterator<any> | undefined
+        ): LoDashImplicitObjectWrapper<Dictionary<string>>
+    }
+
+    interface LoDashExplicitStringWrapper {
+        /**
+         * @see _.keyBy
+         */
+        keyBy(
+            iteratee?: StringIterator<any> | undefined
+        ): LoDashExplicitObjectWrapper<Dictionary<string>>
+    }
+
     interface LoDashImplicitWrapper<T> {
         /**
          * @see _.keyBy
@@ -8849,53 +8934,53 @@ declare namespace _ {
             accumulator: TResult): TResult;
 
         /**
-        * @see _.reduce
-        **/
+         * @see _.reduce
+         **/
         reduce<T, TResult>(
             collection: List<T> | null | undefined,
             callback: MemoIterator<T, TResult>,
             accumulator: TResult): TResult;
 
         /**
-        * @see _.reduce
-        **/
+         * @see _.reduce
+         **/
         reduce<T, TResult>(
             collection: Dictionary<T> | null | undefined,
             callback: MemoIterator<T, TResult>,
             accumulator: TResult): TResult;
 
         /**
-        * @see _.reduce
-        **/
+         * @see _.reduce
+         **/
         reduce<T, TResult>(
             collection: NumericDictionary<T> | null | undefined,
             callback: MemoIterator<T, TResult>,
             accumulator: TResult): TResult;
 
         /**
-        * @see _.reduce
-        **/
+         * @see _.reduce
+         **/
         reduce<T, TResult>(
             collection: T[] | null | undefined,
             callback: MemoIterator<T, TResult>): TResult | undefined;
 
         /**
-        * @see _.reduce
-        **/
+         * @see _.reduce
+         **/
         reduce<T, TResult>(
             collection: List<T> | null | undefined,
             callback: MemoIterator<T, TResult>): TResult | undefined;
 
         /**
-        * @see _.reduce
-        **/
+         * @see _.reduce
+         **/
         reduce<T, TResult>(
             collection: Dictionary<T> | null | undefined,
             callback: MemoIterator<T, TResult>): TResult | undefined;
 
         /**
-        * @see _.reduce
-        **/
+         * @see _.reduce
+         **/
         reduce<T, TResult>(
             collection: NumericDictionary<T> | null | undefined,
             callback: MemoIterator<T, TResult>): TResult | undefined;
@@ -12606,7 +12691,7 @@ declare namespace _ {
     }
 
     //_.isMatchWith
-    type isMatchWithCustomizer = (value: any, other: any, indexOrKey?: number|string) => boolean;
+    type isMatchWithCustomizer = (value: any, other: any, indexOrKey: number|string) => boolean;
 
     interface LoDashStatic {
         /**
@@ -14155,7 +14240,7 @@ declare namespace _ {
          * @see _.sumBy
          */
         sumBy(
-            iteratee: ListIterator<{}, number>
+            iteratee: ListIterator<TObject, number>
         ): number;
 
         /**
@@ -14198,7 +14283,7 @@ declare namespace _ {
          * @see _.sumBy
          */
         sumBy(
-            iteratee: ListIterator<{}, number>
+            iteratee: ListIterator<TObject, number>
         ): LoDashExplicitWrapper<number>;
 
         /**
@@ -16955,7 +17040,7 @@ declare namespace _ {
     }
 
     //_.mergeWith
-    type MergeWithCustomizer = (value: any, srcValue: any, key?: string, object?: Object, source?: Object) => any;
+    type MergeWithCustomizer = { bivariantHack(value: any, srcValue: any, key: string, object: any, source: any): any; }["bivariantHack"]
 
     interface LoDashStatic {
         /**
@@ -17438,31 +17523,31 @@ declare namespace _ {
          * @parem customizer The function to customize assigned values.
          * @return Returns object.
          */
+        setWith<O, V, TResult>(
+            object: O,
+            path: Many<StringRepresentable>,
+            value: V,
+            customizer?: SetWithCustomizer<O>
+        ): TResult;
+
+        /**
+         * @see _.setWith
+         */
         setWith<TResult>(
-            object: Object,
+            object: any,
             path: Many<StringRepresentable>,
             value: any,
-            customizer?: SetWithCustomizer<Object>
+            customizer?: SetWithCustomizer<any>
         ): TResult;
 
         /**
          * @see _.setWith
          */
         setWith<V, TResult>(
-            object: Object,
+            object: any,
             path: Many<StringRepresentable>,
             value: V,
-            customizer?: SetWithCustomizer<Object>
-        ): TResult;
-
-        /**
-         * @see _.setWith
-         */
-        setWith<O, V, TResult>(
-            object: O,
-            path: Many<StringRepresentable>,
-            value: V,
-            customizer?: SetWithCustomizer<O>
+            customizer?: SetWithCustomizer<any>
         ): TResult;
     }
 
@@ -17782,22 +17867,22 @@ declare namespace _ {
          * _.updateWith(object, '[0][1]', _.constant('a'), Object);
          * // => { '0': { '1': 'a' } }
          */
-        updateWith<TResult>(
-            object: Object,
-            path: Many<StringRepresentable>,
-            updater: (oldValue: any) => any,
-            customizer?: SetWithCustomizer<Object>
-        ): TResult;
-
-        /**
-         * @see _.updateWith
-         */
         updateWith<O extends {}, TResult>(
             object: O,
             path: Many<StringRepresentable>,
             updater: (oldValue: any) => any,
             customizer?: SetWithCustomizer<O>
         ): TResult;
+
+        /**
+         * @see _.updateWith
+         */
+        updateWith<TResult>(
+            object: any,
+            path: Many<StringRepresentable>,
+            updater: (oldValue: any) => any,
+            customizer?: SetWithCustomizer<any>
+        ): TResult;
     }
 
     interface LoDashImplicitObjectWrapper<T> {
diff --git a/types/lodash/lodash-tests.ts b/types/lodash/lodash-tests.ts
index ed80175d6f..3e13b70ac8 100644
--- a/types/lodash/lodash-tests.ts
+++ b/types/lodash/lodash-tests.ts
@@ -2256,7 +2256,7 @@ namespace TestUniqBy {
         let result: string[];
 
         result = _.uniqBy<string>('abc', stringIterator);
-        result = _.uniqBy<string, string>('abc', stringIterator);
+        result = _.uniqBy('abc', stringIterator);
     }
 
     {
@@ -2278,7 +2278,7 @@ namespace TestUniqBy {
     {
         let result: _.LoDashImplicitArrayWrapper<string>;
 
-        result = _('abc').uniqBy<string>(stringIterator);
+        result = _('abc').uniqBy(stringIterator);
     }
 
     {
@@ -2298,7 +2298,7 @@ namespace TestUniqBy {
     {
         let result: _.LoDashExplicitArrayWrapper<string>;
 
-        result = _('abc').chain().uniqBy<string>(stringIterator);
+        result = _('abc').chain().uniqBy(stringIterator);
     }
 
     {
@@ -2371,7 +2371,7 @@ namespace TestSortedUniqBy {
         let result: string[];
 
         result = _.sortedUniqBy<string>('abc', stringIterator);
-        result = _.sortedUniqBy<string, string>('abc', stringIterator);
+        result = _.sortedUniqBy('abc', stringIterator);
     }
 
     {
@@ -2393,7 +2393,7 @@ namespace TestSortedUniqBy {
     {
         let result: _.LoDashImplicitArrayWrapper<string>;
 
-        result = _('abc').sortedUniqBy<string>(stringIterator);
+        result = _('abc').sortedUniqBy(stringIterator);
     }
 
     {
@@ -2413,7 +2413,7 @@ namespace TestSortedUniqBy {
     {
         let result: _.LoDashExplicitArrayWrapper<string>;
 
-        result = _('abc').chain().sortedUniqBy<string>(stringIterator);
+        result = _('abc').chain().sortedUniqBy(stringIterator);
     }
 
     {
@@ -3345,7 +3345,7 @@ namespace TestCountBy {
     let dictionary: _.Dictionary<TResult> | null | undefined = obj;
     let numericDictionary: _.NumericDictionary<TResult> | null | undefined = obj;
 
-    let stringIterator: (value: string, index: number, collection: string) => any = (value: string, index: number, collection: string) => 1;
+    let stringIterator: (value: string, index: number, collection: ArrayLike<string>) => any = (value: string, index: number, collection: ArrayLike<string>) => 1;
     let listIterator: (value: TResult, index: number, collection: _.List<TResult>) => any = (value: TResult, index: number, collection: _.List<TResult>) => 1;
     let dictionaryIterator: (value: TResult, key: string, collection: _.Dictionary<TResult>) => any = (value: TResult, key: string, collection: _.Dictionary<TResult>) => 1;
     let numericDictionaryIterator: (value: TResult, key: number, collection: _.NumericDictionary<TResult>) => any = (value: TResult, key: number, collection: _.NumericDictionary<TResult>) => 1;
@@ -4557,7 +4557,7 @@ namespace TestForEach {
 
     {
         let result: TResult[];
-        result = _.forEach(array, (value, index, collection: TResult[]) => {
+        result = _.forEach(array, (value, index, collection: ArrayLike<TResult>) => {
             value; // $ExpectType TResult
             index; // $ExpectType number
         });
@@ -4572,7 +4572,7 @@ namespace TestForEach {
     {
         let result: TResult[] | null | undefined;
 
-        result = _.forEach(array, (value, index, collection: TResult[]) => {
+        result = _.forEach(array, (value, index, collection: ArrayLike<TResult>) => {
             value; // $ExpectType TResult
             index; // $ExpectType number
         });
@@ -4990,7 +4990,7 @@ namespace TestGroupBy {
         let result: _.LoDashImplicitObjectWrapper<_.Dictionary<string[]>>;
 
         result = _('').groupBy();
-        result = _('').groupBy<number>(stringIterator);
+        result = _('').groupBy<number>((char: string, index: number, string: ArrayLike<string>) => 0);
     }
 
     {
@@ -5025,7 +5025,7 @@ namespace TestGroupBy {
         let result: _.LoDashExplicitObjectWrapper<_.Dictionary<string[]>>;
 
         result = _('').chain().groupBy();
-        result = _('').chain().groupBy<number>(stringIterator);
+        result = _('').chain().groupBy<number>((char: string, index: number, string: ArrayLike<string>) => 0);
     }
 
     {
@@ -5547,7 +5547,7 @@ namespace TestReduce {
     result = <ABC>_.reduce({ 'a': 1, 'b': 2, 'c': 3 }, (r: ABC, num: number, key: string) => {
         r[key] = num * 3;
         return r;
-    }, {});
+    }, {} as ABC);
 
     result = <number>_([1, 2, 3]).reduce<number>((sum: number, num: number) => sum + num);
     result = <ABC>_({ 'a': 1, 'b': 2, 'c': 3 }).reduce<number, ABC>((r: ABC, num: number, key: string) => {
@@ -6487,6 +6487,7 @@ namespace TestDebounce {
     interface ResultFunc {
         (n: number, s: string): boolean;
         cancel(): void;
+        flush(): void;
     }
 
     let func: SampleFunc = (a, b) => true;
@@ -6959,6 +6960,7 @@ namespace TestThrottle {
     interface ResultFunc {
         (n: number, s: string): boolean;
         cancel(): void;
+        flush(): void;
     }
 
     let func: SampleFunc = (a, b) => true;
@@ -8980,7 +8982,7 @@ namespace TestSumBy {
         result = _(array).sumBy(listIterator);
         result = _(objectArray).sumBy('age');
 
-        result = _(list).sumBy(listIterator);
+        result = _(list).sumBy((value: _.List<number> | null | undefined, index: number, collection: _.List<_.List<number> | null | undefined>) => 0);
         result = _(objectList).sumBy('age');
     }
 
@@ -8990,7 +8992,7 @@ namespace TestSumBy {
         result = _(array).chain().sumBy(listIterator);
         result = _(objectArray).chain().sumBy('age');
 
-        result = _(list).chain().sumBy(listIterator);
+        result = _(list).chain().sumBy((value: _.List<number> | null | undefined, index: number, collection: _.List<_.List<number> | null | undefined>) => 0);
         result = _(objectList).chain().sumBy('age');
     }
 }
@@ -9146,25 +9148,25 @@ namespace TestAssign {
     }
 
     {
-        let result: _.LoDashImplicitObjectWrapper<{ a: number }>;
+        let result: _.LoDashImplicitObjectWrapper<{ a: number & string }>;
 
         result = _(obj).assign(s1);
     }
 
     {
-        let result: _.LoDashImplicitObjectWrapper<{ a: number, b: number }>;
+        let result: _.LoDashImplicitObjectWrapper<{ a: number & string, b: number }>;
 
         result = _(obj).assign(s1, s2);
     }
 
     {
-        let result: _.LoDashImplicitObjectWrapper<{ a: number, b: number, c: number }>;
+        let result: _.LoDashImplicitObjectWrapper<{ a: number & string, b: number, c: number }>;
 
         result = _(obj).assign(s1, s2, s3);
     }
 
     {
-        let result: _.LoDashImplicitObjectWrapper<{ a: number, b: number, c: number, d: number }>;
+        let result: _.LoDashImplicitObjectWrapper<{ a: number & string, b: number, c: number, d: number }>;
 
         result = _(obj).assign(s1, s2, s3, s4);
     }
@@ -9182,25 +9184,25 @@ namespace TestAssign {
     }
 
     {
-        let result: _.LoDashExplicitObjectWrapper<{ a: number }>;
+        let result: _.LoDashExplicitObjectWrapper<{ a: number & string }>;
 
         result = _(obj).chain().assign(s1);
     }
 
     {
-        let result: _.LoDashExplicitObjectWrapper<{ a: number, b: number }>;
+        let result: _.LoDashExplicitObjectWrapper<{ a: number & string, b: number }>;
 
         result = _(obj).chain().assign(s1, s2);
     }
 
     {
-        let result: _.LoDashExplicitObjectWrapper<{ a: number, b: number, c: number }>;
+        let result: _.LoDashExplicitObjectWrapper<{ a: number & string, b: number, c: number }>;
 
         result = _(obj).chain().assign(s1, s2, s3);
     }
 
     {
-        let result: _.LoDashExplicitObjectWrapper<{ a: number, b: number, c: number, d: number }>;
+        let result: _.LoDashExplicitObjectWrapper<{ a: number & string, b: number, c: number, d: number }>;
 
         result = _(obj).chain().assign(s1, s2, s3, s4);
     }
@@ -9268,22 +9270,22 @@ namespace TestAssignWith {
     }
 
     {
-        let result: _.LoDashImplicitObjectWrapper<{ a: number }>;
+        let result: _.LoDashImplicitObjectWrapper<{ a: number & string }>;
         result = _(obj).assignWith(s1, customizer);
     }
 
     {
-        let result: _.LoDashImplicitObjectWrapper<{ a: number, b: number }>;
+        let result: _.LoDashImplicitObjectWrapper<{ a: number & string, b: number }>;
         result = _(obj).assignWith(s1, s2, customizer);
     }
 
     {
-        let result: _.LoDashImplicitObjectWrapper<{ a: number, b: number, c: number }>;
+        let result: _.LoDashImplicitObjectWrapper<{ a: number & string, b: number, c: number }>;
         result = _(obj).assignWith(s1, s2, s3, customizer);
     }
 
     {
-        let result: _.LoDashImplicitObjectWrapper<{ a: number, b: number, c: number, d: number }>;
+        let result: _.LoDashImplicitObjectWrapper<{ a: number & string, b: number, c: number, d: number }>;
         result = _(obj).assignWith(s1, s2, s3, s4, customizer);
     }
 
@@ -9299,22 +9301,22 @@ namespace TestAssignWith {
     }
 
     {
-        let result: _.LoDashExplicitObjectWrapper<{ a: number }>;
+        let result: _.LoDashExplicitObjectWrapper<{ a: number & string }>;
         result = _(obj).chain().assignWith(s1, customizer);
     }
 
     {
-        let result: _.LoDashExplicitObjectWrapper<{ a: number, b: number }>;
+        let result: _.LoDashExplicitObjectWrapper<{ a: number & string, b: number }>;
         result = _(obj).chain().assignWith(s1, s2, customizer);
     }
 
     {
-        let result: _.LoDashExplicitObjectWrapper<{ a: number, b: number, c: number }>;
+        let result: _.LoDashExplicitObjectWrapper<{ a: number & string, b: number, c: number }>;
         result = _(obj).chain().assignWith(s1, s2, s3, customizer);
     }
 
     {
-        let result: _.LoDashExplicitObjectWrapper<{ a: number, b: number, c: number, d: number }>;
+        let result: _.LoDashExplicitObjectWrapper<{ a: number & string, b: number, c: number, d: number }>;
         result = _(obj).chain().assignWith(s1, s2, s3, s4, customizer);
     }
 
@@ -9385,25 +9387,25 @@ namespace TestAssignIn {
     }
 
     {
-        let result: _.LoDashImplicitObjectWrapper<{ a: number }>;
+        let result: _.LoDashImplicitObjectWrapper<{ a: number & string }>;
 
         result = _(obj).assignIn(s1);
     }
 
     {
-        let result: _.LoDashImplicitObjectWrapper<{ a: number, b: number }>;
+        let result: _.LoDashImplicitObjectWrapper<{ a: number & string, b: number }>;
 
         result = _(obj).assignIn(s1, s2);
     }
 
     {
-        let result: _.LoDashImplicitObjectWrapper<{ a: number, b: number, c: number }>;
+        let result: _.LoDashImplicitObjectWrapper<{ a: number & string, b: number, c: number }>;
 
         result = _(obj).assignIn(s1, s2, s3);
     }
 
     {
-        let result: _.LoDashImplicitObjectWrapper<{ a: number, b: number, c: number, d: number }>;
+        let result: _.LoDashImplicitObjectWrapper<{ a: number & string, b: number, c: number, d: number }>;
 
         result = _(obj).assignIn(s1, s2, s3, s4);
     }
@@ -9421,25 +9423,25 @@ namespace TestAssignIn {
     }
 
     {
-        let result: _.LoDashExplicitObjectWrapper<{ a: number }>;
+        let result: _.LoDashExplicitObjectWrapper<{ a: number & string }>;
 
         result = _(obj).chain().assignIn(s1);
     }
 
     {
-        let result: _.LoDashExplicitObjectWrapper<{ a: number, b: number }>;
+        let result: _.LoDashExplicitObjectWrapper<{ a: number & string, b: number }>;
 
         result = _(obj).chain().assignIn(s1, s2);
     }
 
     {
-        let result: _.LoDashExplicitObjectWrapper<{ a: number, b: number, c: number }>;
+        let result: _.LoDashExplicitObjectWrapper<{ a: number & string, b: number, c: number }>;
 
         result = _(obj).chain().assignIn(s1, s2, s3);
     }
 
     {
-        let result: _.LoDashExplicitObjectWrapper<{ a: number, b: number, c: number, d: number }>;
+        let result: _.LoDashExplicitObjectWrapper<{ a: number & string, b: number, c: number, d: number }>;
 
         result = _(obj).chain().assignIn(s1, s2, s3, s4);
     }
@@ -9507,22 +9509,22 @@ namespace TestAssignInWith {
     }
 
     {
-        let result: _.LoDashImplicitObjectWrapper<{ a: number }>;
+        let result: _.LoDashImplicitObjectWrapper<{ a: number & string }>;
         result = _(obj).assignInWith(s1, customizer);
     }
 
     {
-        let result: _.LoDashImplicitObjectWrapper<{ a: number, b: number }>;
+        let result: _.LoDashImplicitObjectWrapper<{ a: number & string, b: number }>;
         result = _(obj).assignInWith(s1, s2, customizer);
     }
 
     {
-        let result: _.LoDashImplicitObjectWrapper<{ a: number, b: number, c: number }>;
+        let result: _.LoDashImplicitObjectWrapper<{ a: number & string, b: number, c: number }>;
         result = _(obj).assignInWith(s1, s2, s3, customizer);
     }
 
     {
-        let result: _.LoDashImplicitObjectWrapper<{ a: number, b: number, c: number, d: number }>;
+        let result: _.LoDashImplicitObjectWrapper<{ a: number & string, b: number, c: number, d: number }>;
         result = _(obj).assignInWith(s1, s2, s3, s4, customizer);
     }
 
@@ -9538,22 +9540,22 @@ namespace TestAssignInWith {
     }
 
     {
-        let result: _.LoDashExplicitObjectWrapper<{ a: number }>;
+        let result: _.LoDashExplicitObjectWrapper<{ a: number & string }>;
         result = _(obj).chain().assignInWith(s1, customizer);
     }
 
     {
-        let result: _.LoDashExplicitObjectWrapper<{ a: number, b: number }>;
+        let result: _.LoDashExplicitObjectWrapper<{ a: number & string, b: number }>;
         result = _(obj).chain().assignInWith(s1, s2, customizer);
     }
 
     {
-        let result: _.LoDashExplicitObjectWrapper<{ a: number, b: number, c: number }>;
+        let result: _.LoDashExplicitObjectWrapper<{ a: number & string, b: number, c: number }>;
         result = _(obj).chain().assignInWith(s1, s2, s3, customizer);
     }
 
     {
-        let result: _.LoDashExplicitObjectWrapper<{ a: number, b: number, c: number, d: number }>;
+        let result: _.LoDashExplicitObjectWrapper<{ a: number & string, b: number, c: number, d: number }>;
         result = _(obj).chain().assignInWith(s1, s2, s3, s4, customizer);
     }
 
@@ -9652,25 +9654,25 @@ namespace TestDefaults {
     }
 
     {
-    let result: _.LoDashImplicitObjectWrapper<{ a: string }>;
+    let result: _.LoDashImplicitObjectWrapper<{ a: string & number }>;
 
     result = _(obj).defaults(s1);
     }
 
     {
-    let result: _.LoDashImplicitObjectWrapper<{ a: string, b: number }>;
+    let result: _.LoDashImplicitObjectWrapper<{ a: string & number, b: number }>;
 
     result = _(obj).defaults(s1, s2);
     }
 
     {
-    let result: _.LoDashImplicitObjectWrapper<{ a: string, b: number, c: number }>;
+    let result: _.LoDashImplicitObjectWrapper<{ a: string & number, b: number, c: number }>;
 
     result = _(obj).defaults(s1, s2, s3);
     }
 
     {
-    let result: _.LoDashImplicitObjectWrapper<{ a: string, b: number, c: number, d: number }>;
+    let result: _.LoDashImplicitObjectWrapper<{ a: string & number, b: number, c: number, d: number }>;
 
     result = _(obj).defaults(s1, s2, s3, s4);
     }
@@ -9688,25 +9690,25 @@ namespace TestDefaults {
     }
 
     {
-    let result: _.LoDashExplicitObjectWrapper<{ a: string }>;
+    let result: _.LoDashExplicitObjectWrapper<{ a: string & number }>;
 
     result = _(obj).chain().defaults(s1);
     }
 
     {
-    let result: _.LoDashExplicitObjectWrapper<{ a: string, b: number }>;
+    let result: _.LoDashExplicitObjectWrapper<{ a: string & number, b: number }>;
 
     result = _(obj).chain().defaults(s1, s2);
     }
 
     {
-    let result: _.LoDashExplicitObjectWrapper<{ a: string, b: number, c: number }>;
+    let result: _.LoDashExplicitObjectWrapper<{ a: string & number, b: number, c: number }>;
 
     result = _(obj).chain().defaults(s1, s2, s3);
     }
 
     {
-    let result: _.LoDashExplicitObjectWrapper<{ a: string, b: number, c: number, d: number }>;
+    let result: _.LoDashExplicitObjectWrapper<{ a: string & number, b: number, c: number, d: number }>;
 
     result = _(obj).chain().defaults(s1, s2, s3, s4);
     }
@@ -9873,25 +9875,25 @@ namespace TestExtend {
     }
 
     {
-        let result: _.LoDashImplicitObjectWrapper<{ a: number }>;
+        let result: _.LoDashImplicitObjectWrapper<{ a: number & string }>;
 
         result = _(obj).extend(s1);
     }
 
     {
-        let result: _.LoDashImplicitObjectWrapper<{ a: number, b: number }>;
+        let result: _.LoDashImplicitObjectWrapper<{ a: number & string, b: number }>;
 
         result = _(obj).extend(s1, s2);
     }
 
     {
-        let result: _.LoDashImplicitObjectWrapper<{ a: number, b: number, c: number }>;
+        let result: _.LoDashImplicitObjectWrapper<{ a: number & string, b: number, c: number }>;
 
         result = _(obj).extend(s1, s2, s3);
     }
 
     {
-        let result: _.LoDashImplicitObjectWrapper<{ a: number, b: number, c: number, d: number }>;
+        let result: _.LoDashImplicitObjectWrapper<{ a: number & string, b: number, c: number, d: number }>;
 
         result = _(obj).extend(s1, s2, s3, s4);
     }
@@ -9909,25 +9911,25 @@ namespace TestExtend {
     }
 
     {
-        let result: _.LoDashExplicitObjectWrapper<{ a: number }>;
+        let result: _.LoDashExplicitObjectWrapper<{ a: number & string }>;
 
         result = _(obj).chain().extend(s1);
     }
 
     {
-        let result: _.LoDashExplicitObjectWrapper<{ a: number, b: number }>;
+        let result: _.LoDashExplicitObjectWrapper<{ a: number & string, b: number }>;
 
         result = _(obj).chain().extend(s1, s2);
     }
 
     {
-        let result: _.LoDashExplicitObjectWrapper<{ a: number, b: number, c: number }>;
+        let result: _.LoDashExplicitObjectWrapper<{ a: number & string, b: number, c: number }>;
 
         result = _(obj).chain().extend(s1, s2, s3);
     }
 
     {
-        let result: _.LoDashExplicitObjectWrapper<{ a: number, b: number, c: number, d: number }>;
+        let result: _.LoDashExplicitObjectWrapper<{ a: number & string, b: number, c: number, d: number }>;
 
         result = _(obj).chain().extend(s1, s2, s3, s4);
     }
@@ -10000,25 +10002,25 @@ namespace TestExtendWith {
     }
 
     {
-        let result: _.LoDashImplicitObjectWrapper<{ a: number }>;
+        let result: _.LoDashImplicitObjectWrapper<{ a: number & string }>;
 
         result = _(obj).extendWith(s1, customizer);
     }
 
     {
-        let result: _.LoDashImplicitObjectWrapper<{ a: number, b: number }>;
+        let result: _.LoDashImplicitObjectWrapper<{ a: number & string, b: number }>;
 
         result = _(obj).extendWith(s1, s2, customizer);
     }
 
     {
-        let result: _.LoDashImplicitObjectWrapper<{ a: number, b: number, c: number }>;
+        let result: _.LoDashImplicitObjectWrapper<{ a: number & string, b: number, c: number }>;
 
         result = _(obj).extendWith(s1, s2, s3, customizer);
     }
 
     {
-        let result: _.LoDashImplicitObjectWrapper<{ a: number, b: number, c: number, d: number }>;
+        let result: _.LoDashImplicitObjectWrapper<{ a: number & string, b: number, c: number, d: number }>;
 
         result = _(obj).extendWith(s1, s2, s3, s4, customizer);
     }
@@ -10036,25 +10038,25 @@ namespace TestExtendWith {
     }
 
     {
-        let result: _.LoDashExplicitObjectWrapper<{ a: number }>;
+        let result: _.LoDashExplicitObjectWrapper<{ a: number & string }>;
 
         result = _(obj).chain().extendWith(s1, customizer);
     }
 
     {
-        let result: _.LoDashExplicitObjectWrapper<{ a: number, b: number }>;
+        let result: _.LoDashExplicitObjectWrapper<{ a: number & string, b: number }>;
 
         result = _(obj).chain().extendWith(s1, s2, customizer);
     }
 
     {
-        let result: _.LoDashExplicitObjectWrapper<{ a: number, b: number, c: number }>;
+        let result: _.LoDashExplicitObjectWrapper<{ a: number & string, b: number, c: number }>;
 
         result = _(obj).chain().extendWith(s1, s2, s3, customizer);
     }
 
     {
-        let result: _.LoDashExplicitObjectWrapper<{ a: number, b: number, c: number, d: number }>;
+        let result: _.LoDashExplicitObjectWrapper<{ a: number & string, b: number, c: number, d: number }>;
 
         result = _(obj).chain().extendWith(s1, s2, s3, s4, customizer);
     }
@@ -10986,7 +10988,7 @@ namespace TestMergeWith {
     type ExpectedResult = { a: number, b: string };
     let result: ExpectedResult;
 
-    let customizer: (value: any, srcValue: any, key?: string, object?: InitialValue, source?: MergingValue) => any = (value: any, srcValue: any, key?: string, object?: InitialValue, source?: MergingValue) => 1;
+    let customizer: (value: any, srcValue: any, key: string, object: InitialValue, source: MergingValue) => any = (value: any, srcValue: any, key: string, object: InitialValue, source: MergingValue) => 1;
 
     // Test for basic merging
     result = _.mergeWith(initialValue, mergingValue, customizer);
@@ -11003,7 +11005,7 @@ namespace TestMergeWith {
     result = _(initialValue).mergeWith({}, {}, mergingValue, customizer).value();
     result = _(initialValue).mergeWith({}, {}, {}, mergingValue, customizer).value();
 
-    // Once we get to the varargs version, you have to specify the result explicitl
+    // Once we get to the varargs version, you have to specify the result explicitly
     result = _(initialValue).mergeWith<ExpectedResult>({}, {}, {}, {}, mergingValue, customizer).value();
 }
 
diff --git a/types/lodash/tsconfig.json b/types/lodash/tsconfig.json
index 8239e4f277..5ba4c4bcf6 100644
--- a/types/lodash/tsconfig.json
+++ b/types/lodash/tsconfig.json
@@ -7,6 +7,7 @@
         "noImplicitAny": true,
         "noImplicitThis": true,
         "strictNullChecks": true,
+        "strictFunctionTypes": true,
         "baseUrl": "../",
         "typeRoots": [
             "../"
@@ -315,4 +316,4 @@
         "zipObjectDeep.d.ts",
         "zipWith.d.ts"
     ]
-}
\ No newline at end of file
+}
diff --git a/types/log4js/log4js-tests.ts b/types/log4js/log4js-tests.ts
index af4a706e1c..9ab50d3344 100644
--- a/types/log4js/log4js-tests.ts
+++ b/types/log4js/log4js-tests.ts
@@ -90,10 +90,10 @@ var myAppender: log4js.AppenderModule = {
     return cb(null);
   },
 
-  configure: function (config: MyAppenderConfig, options?: { [key: string]: any }): log4js.Appender {
+  configure: function (config: log4js.CustomAppenderConfig, options?: { [key: string]: any }): log4js.Appender {
     var mycfg = config.mycfg;
     return this.appender(mycfg);
   }
 }
 
-log4js.loadAppender("my-log4js-appender", myAppender);
\ No newline at end of file
+log4js.loadAppender("my-log4js-appender", myAppender);
diff --git a/types/log4js/tsconfig.json b/types/log4js/tsconfig.json
index a71e03c82a..ea6450c12b 100644
--- a/types/log4js/tsconfig.json
+++ b/types/log4js/tsconfig.json
@@ -7,6 +7,7 @@
         "noImplicitAny": true,
         "noImplicitThis": false,
         "strictNullChecks": false,
+        "strictFunctionTypes": true,
         "baseUrl": "../",
         "typeRoots": [
             "../"
@@ -19,4 +20,4 @@
         "index.d.ts",
         "log4js-tests.ts"
     ]
-}
\ No newline at end of file
+}
diff --git a/types/node/node-tests.ts b/types/node/node-tests.ts
index bfd1eaa02e..4c31be7ea8 100644
--- a/types/node/node-tests.ts
+++ b/types/node/node-tests.ts
@@ -2252,8 +2252,8 @@ namespace process_tests {
         process.once("warning", (warning: Error) => { });
         process.prependListener("message", (message: any, sendHandle: any) => { });
         process.prependOnceListener("SIGBREAK", () => { });
-        process.on("newListener", (event: string, listener: Function) => { });
-        process.once("removeListener", (event: string, listener: Function) => { });
+        process.on("newListener", (event: string | symbol, listener: Function) => { });
+        process.once("removeListener", (event: string | symbol, listener: Function) => { });
 
         const listeners = process.listeners('uncaughtException');
         const oldHandler = listeners[listeners.length - 1];