diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index c6260a958dea3..f93a60b9281ef 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -12034,8 +12034,8 @@ namespace ts {
                 }
 
                 if (target.flags & TypeFlags.TypeParameter) {
-                    // A source type { [P in keyof T]: X } is related to a target type T if X is related to T[P].
-                    if (getObjectFlags(source) & ObjectFlags.Mapped && getConstraintTypeFromMappedType(<MappedType>source) === getIndexType(target)) {
+                    // A source type { [P in Q]: X } is related to a target type T if keyof T is related to Q and X is related to T[Q].
+                    if (getObjectFlags(source) & ObjectFlags.Mapped && isRelatedTo(getIndexType(target), getConstraintTypeFromMappedType(<MappedType>source))) {
                         if (!(getMappedTypeModifiers(<MappedType>source) & MappedTypeModifiers.IncludeOptional)) {
                             const templateType = getTemplateTypeFromMappedType(<MappedType>source);
                             const indexedAccessType = getIndexedAccessType(target, getTypeParameterFromMappedType(<MappedType>source));
@@ -12089,7 +12089,7 @@ namespace ts {
                             (<IndexedAccessType>template).indexType === getTypeParameterFromMappedType(target)) {
                             return Ternary.True;
                         }
-                        // A source type T is related to a target type { [P in keyof T]: X } if T[P] is related to X.
+                        // A source type T is related to a target type { [P in Q]: X } if Q is related to keyof T and T[Q] is related to X.
                         if (!isGenericMappedType(source) && isRelatedTo(getConstraintTypeFromMappedType(target), getIndexType(source))) {
                             const indexedAccessType = getIndexedAccessType(source, getTypeParameterFromMappedType(target));
                             const templateType = getTemplateTypeFromMappedType(target);
diff --git a/tests/baselines/reference/reactHOCSpreadprops.js b/tests/baselines/reference/reactHOCSpreadprops.js
new file mode 100644
index 0000000000000..45ecbe35f6829
--- /dev/null
+++ b/tests/baselines/reference/reactHOCSpreadprops.js
@@ -0,0 +1,53 @@
+//// [reactHOCSpreadprops.tsx]
+/// <reference path="/.lib/react16.d.ts" />
+import React = require("react");
+function f<P>(App: React.ComponentClass<P> | React.StatelessComponent<P>): void {
+    class C extends React.Component<P & { x: number }> {
+        render() {
+            return <App {...this.props} />;
+        }
+    }
+}
+
+
+//// [reactHOCSpreadprops.js]
+"use strict";
+var __extends = (this && this.__extends) || (function () {
+    var extendStatics = function (d, b) {
+        extendStatics = Object.setPrototypeOf ||
+            ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
+            function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; };
+        return extendStatics(d, b);
+    };
+    return function (d, b) {
+        extendStatics(d, b);
+        function __() { this.constructor = d; }
+        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+    };
+})();
+var __assign = (this && this.__assign) || function () {
+    __assign = Object.assign || function(t) {
+        for (var s, i = 1, n = arguments.length; i < n; i++) {
+            s = arguments[i];
+            for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+                t[p] = s[p];
+        }
+        return t;
+    };
+    return __assign.apply(this, arguments);
+};
+exports.__esModule = true;
+/// <reference path="react16.d.ts" />
+var React = require("react");
+function f(App) {
+    var C = /** @class */ (function (_super) {
+        __extends(C, _super);
+        function C() {
+            return _super !== null && _super.apply(this, arguments) || this;
+        }
+        C.prototype.render = function () {
+            return React.createElement(App, __assign({}, this.props));
+        };
+        return C;
+    }(React.Component));
+}
diff --git a/tests/baselines/reference/reactHOCSpreadprops.symbols b/tests/baselines/reference/reactHOCSpreadprops.symbols
new file mode 100644
index 0000000000000..06e698014f4ab
--- /dev/null
+++ b/tests/baselines/reference/reactHOCSpreadprops.symbols
@@ -0,0 +1,36 @@
+=== tests/cases/compiler/reactHOCSpreadprops.tsx ===
+/// <reference path="react16.d.ts" />
+import React = require("react");
+>React : Symbol(React, Decl(reactHOCSpreadprops.tsx, 0, 0))
+
+function f<P>(App: React.ComponentClass<P> | React.StatelessComponent<P>): void {
+>f : Symbol(f, Decl(reactHOCSpreadprops.tsx, 1, 32))
+>P : Symbol(P, Decl(reactHOCSpreadprops.tsx, 2, 11))
+>App : Symbol(App, Decl(reactHOCSpreadprops.tsx, 2, 14))
+>React : Symbol(React, Decl(reactHOCSpreadprops.tsx, 0, 0))
+>ComponentClass : Symbol(React.ComponentClass, Decl(react16.d.ts, 421, 9))
+>P : Symbol(P, Decl(reactHOCSpreadprops.tsx, 2, 11))
+>React : Symbol(React, Decl(reactHOCSpreadprops.tsx, 0, 0))
+>StatelessComponent : Symbol(React.StatelessComponent, Decl(react16.d.ts, 406, 49))
+>P : Symbol(P, Decl(reactHOCSpreadprops.tsx, 2, 11))
+
+    class C extends React.Component<P & { x: number }> {
+>C : Symbol(C, Decl(reactHOCSpreadprops.tsx, 2, 81))
+>React.Component : Symbol(React.Component, Decl(react16.d.ts, 345, 54), Decl(react16.d.ts, 349, 94))
+>React : Symbol(React, Decl(reactHOCSpreadprops.tsx, 0, 0))
+>Component : Symbol(React.Component, Decl(react16.d.ts, 345, 54), Decl(react16.d.ts, 349, 94))
+>P : Symbol(P, Decl(reactHOCSpreadprops.tsx, 2, 11))
+>x : Symbol(x, Decl(reactHOCSpreadprops.tsx, 3, 41))
+
+        render() {
+>render : Symbol(C.render, Decl(reactHOCSpreadprops.tsx, 3, 56))
+
+            return <App {...this.props} />;
+>App : Symbol(App, Decl(reactHOCSpreadprops.tsx, 2, 14))
+>this.props : Symbol(React.Component.props, Decl(react16.d.ts, 367, 32))
+>this : Symbol(C, Decl(reactHOCSpreadprops.tsx, 2, 81))
+>props : Symbol(React.Component.props, Decl(react16.d.ts, 367, 32))
+        }
+    }
+}
+
diff --git a/tests/baselines/reference/reactHOCSpreadprops.types b/tests/baselines/reference/reactHOCSpreadprops.types
new file mode 100644
index 0000000000000..b343ea5fc7af3
--- /dev/null
+++ b/tests/baselines/reference/reactHOCSpreadprops.types
@@ -0,0 +1,31 @@
+=== tests/cases/compiler/reactHOCSpreadprops.tsx ===
+/// <reference path="react16.d.ts" />
+import React = require("react");
+>React : typeof React
+
+function f<P>(App: React.ComponentClass<P> | React.StatelessComponent<P>): void {
+>f : <P>(App: React.ComponentClass<P, any> | React.StatelessComponent<P>) => void
+>App : React.ComponentClass<P, any> | React.StatelessComponent<P>
+>React : any
+>React : any
+
+    class C extends React.Component<P & { x: number }> {
+>C : C
+>React.Component : React.Component<P & { x: number; }, {}, any>
+>React : typeof React
+>Component : typeof React.Component
+>x : number
+
+        render() {
+>render : () => JSX.Element
+
+            return <App {...this.props} />;
+><App {...this.props} /> : JSX.Element
+>App : React.ComponentClass<P, any> | React.StatelessComponent<P>
+>this.props : Readonly<{ children?: React.ReactNode; }> & Readonly<P & { x: number; }>
+>this : this
+>props : Readonly<{ children?: React.ReactNode; }> & Readonly<P & { x: number; }>
+        }
+    }
+}
+
diff --git a/tests/cases/compiler/reactHOCSpreadprops.tsx b/tests/cases/compiler/reactHOCSpreadprops.tsx
new file mode 100644
index 0000000000000..3b1b3e747241b
--- /dev/null
+++ b/tests/cases/compiler/reactHOCSpreadprops.tsx
@@ -0,0 +1,11 @@
+// @jsx: react
+// @strict: true
+/// <reference path="/.lib/react16.d.ts" />
+import React = require("react");
+function f<P>(App: React.ComponentClass<P> | React.StatelessComponent<P>): void {
+    class C extends React.Component<P & { x: number }> {
+        render() {
+            return <App {...this.props} />;
+        }
+    }
+}