diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 408739f480..f9ef54cd36 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -8525,16 +8525,9 @@ namespace ts {
                     }
                 }
                 else if (target.flags & TypeFlags.IndexedAccess) {
-                    // if we have indexed access types with identical index types, see if relationship holds for
-                    // the two object types.
-                    if (source.flags & TypeFlags.IndexedAccess && (<IndexedAccessType>source).indexType === (<IndexedAccessType>target).indexType) {
-                        if (result = isRelatedTo((<IndexedAccessType>source).objectType, (<IndexedAccessType>target).objectType, reportErrors)) {
-                            return result;
-                        }
-                    }
                     // A type S is related to a type T[K] if S is related to A[K], where K is string-like and
                     // A is the apparent type of S.
-                    const constraint = getBaseConstraintOfType(target);
+                    const constraint = getConstraintOfType(<IndexedAccessType>target);
                     if (constraint) {
                         if (result = isRelatedTo(source, constraint, reportErrors)) {
                             errorInfo = saveErrorInfo;
@@ -8581,6 +8574,13 @@ namespace ts {
                             return result;
                         }
                     }
+                    else if (target.flags & TypeFlags.IndexedAccess && (<IndexedAccessType>source).indexType === (<IndexedAccessType>target).indexType) {
+                        // if we have indexed access types with identical index types, see if relationship holds for
+                        // the two object types.
+                        if (result = isRelatedTo((<IndexedAccessType>source).objectType, (<IndexedAccessType>target).objectType, reportErrors)) {
+                            return result;
+                        }
+                    }
                 }
                 else {
                     if (getObjectFlags(source) & ObjectFlags.Reference && getObjectFlags(target) & ObjectFlags.Reference && (<TypeReference>source).target === (<TypeReference>target).target) {
diff --git a/tests/baselines/reference/indexedAccessRelation.js b/tests/baselines/reference/indexedAccessRelation.js
new file mode 100644
index 0000000000..c58c214e69
--- /dev/null
+++ b/tests/baselines/reference/indexedAccessRelation.js
@@ -0,0 +1,56 @@
+//// [indexedAccessRelation.ts]
+// Repro from #14723
+
+class Component<S> {
+    setState<K extends keyof S>(state: Pick<S, K>) {}
+}
+
+export interface State<T> {
+    a?: T;
+}
+
+class Foo {}
+
+class Comp<T extends Foo, S> extends Component<S & State<T>>
+{
+    foo(a: T) {
+        this.setState({ a: a });
+    }
+}
+
+
+//// [indexedAccessRelation.js]
+// Repro from #14723
+"use strict";
+var __extends = (this && this.__extends) || (function () {
+    var 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 function (d, b) {
+        extendStatics(d, b);
+        function __() { this.constructor = d; }
+        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+    };
+})();
+exports.__esModule = true;
+var Component = (function () {
+    function Component() {
+    }
+    Component.prototype.setState = function (state) { };
+    return Component;
+}());
+var Foo = (function () {
+    function Foo() {
+    }
+    return Foo;
+}());
+var Comp = (function (_super) {
+    __extends(Comp, _super);
+    function Comp() {
+        return _super !== null && _super.apply(this, arguments) || this;
+    }
+    Comp.prototype.foo = function (a) {
+        this.setState({ a: a });
+    };
+    return Comp;
+}(Component));
diff --git a/tests/baselines/reference/indexedAccessRelation.symbols b/tests/baselines/reference/indexedAccessRelation.symbols
new file mode 100644
index 0000000000..40fa52652f
--- /dev/null
+++ b/tests/baselines/reference/indexedAccessRelation.symbols
@@ -0,0 +1,53 @@
+=== tests/cases/compiler/indexedAccessRelation.ts ===
+// Repro from #14723
+
+class Component<S> {
+>Component : Symbol(Component, Decl(indexedAccessRelation.ts, 0, 0))
+>S : Symbol(S, Decl(indexedAccessRelation.ts, 2, 16))
+
+    setState<K extends keyof S>(state: Pick<S, K>) {}
+>setState : Symbol(Component.setState, Decl(indexedAccessRelation.ts, 2, 20))
+>K : Symbol(K, Decl(indexedAccessRelation.ts, 3, 13))
+>S : Symbol(S, Decl(indexedAccessRelation.ts, 2, 16))
+>state : Symbol(state, Decl(indexedAccessRelation.ts, 3, 32))
+>Pick : Symbol(Pick, Decl(lib.d.ts, --, --))
+>S : Symbol(S, Decl(indexedAccessRelation.ts, 2, 16))
+>K : Symbol(K, Decl(indexedAccessRelation.ts, 3, 13))
+}
+
+export interface State<T> {
+>State : Symbol(State, Decl(indexedAccessRelation.ts, 4, 1))
+>T : Symbol(T, Decl(indexedAccessRelation.ts, 6, 23))
+
+    a?: T;
+>a : Symbol(State.a, Decl(indexedAccessRelation.ts, 6, 27))
+>T : Symbol(T, Decl(indexedAccessRelation.ts, 6, 23))
+}
+
+class Foo {}
+>Foo : Symbol(Foo, Decl(indexedAccessRelation.ts, 8, 1))
+
+class Comp<T extends Foo, S> extends Component<S & State<T>>
+>Comp : Symbol(Comp, Decl(indexedAccessRelation.ts, 10, 12))
+>T : Symbol(T, Decl(indexedAccessRelation.ts, 12, 11))
+>Foo : Symbol(Foo, Decl(indexedAccessRelation.ts, 8, 1))
+>S : Symbol(S, Decl(indexedAccessRelation.ts, 12, 25))
+>Component : Symbol(Component, Decl(indexedAccessRelation.ts, 0, 0))
+>S : Symbol(S, Decl(indexedAccessRelation.ts, 12, 25))
+>State : Symbol(State, Decl(indexedAccessRelation.ts, 4, 1))
+>T : Symbol(T, Decl(indexedAccessRelation.ts, 12, 11))
+{
+    foo(a: T) {
+>foo : Symbol(Comp.foo, Decl(indexedAccessRelation.ts, 13, 1))
+>a : Symbol(a, Decl(indexedAccessRelation.ts, 14, 8))
+>T : Symbol(T, Decl(indexedAccessRelation.ts, 12, 11))
+
+        this.setState({ a: a });
+>this.setState : Symbol(Component.setState, Decl(indexedAccessRelation.ts, 2, 20))
+>this : Symbol(Comp, Decl(indexedAccessRelation.ts, 10, 12))
+>setState : Symbol(Component.setState, Decl(indexedAccessRelation.ts, 2, 20))
+>a : Symbol(a, Decl(indexedAccessRelation.ts, 15, 23))
+>a : Symbol(a, Decl(indexedAccessRelation.ts, 14, 8))
+    }
+}
+
diff --git a/tests/baselines/reference/indexedAccessRelation.types b/tests/baselines/reference/indexedAccessRelation.types
new file mode 100644
index 0000000000..2564a82702
--- /dev/null
+++ b/tests/baselines/reference/indexedAccessRelation.types
@@ -0,0 +1,55 @@
+=== tests/cases/compiler/indexedAccessRelation.ts ===
+// Repro from #14723
+
+class Component<S> {
+>Component : Component<S>
+>S : S
+
+    setState<K extends keyof S>(state: Pick<S, K>) {}
+>setState : <K extends keyof S>(state: Pick<S, K>) => void
+>K : K
+>S : S
+>state : Pick<S, K>
+>Pick : Pick<T, K>
+>S : S
+>K : K
+}
+
+export interface State<T> {
+>State : State<T>
+>T : T
+
+    a?: T;
+>a : T
+>T : T
+}
+
+class Foo {}
+>Foo : Foo
+
+class Comp<T extends Foo, S> extends Component<S & State<T>>
+>Comp : Comp<T, S>
+>T : T
+>Foo : Foo
+>S : S
+>Component : Component<S & State<T>>
+>S : S
+>State : State<T>
+>T : T
+{
+    foo(a: T) {
+>foo : (a: T) => void
+>a : T
+>T : T
+
+        this.setState({ a: a });
+>this.setState({ a: a }) : void
+>this.setState : <K extends keyof (S & State<T>)>(state: Pick<S & State<T>, K>) => void
+>this : this
+>setState : <K extends keyof (S & State<T>)>(state: Pick<S & State<T>, K>) => void
+>{ a: a } : { a: T; }
+>a : T
+>a : T
+    }
+}
+
diff --git a/tests/baselines/reference/mappedTypeRelationships.errors.txt b/tests/baselines/reference/mappedTypeRelationships.errors.txt
index bc26bb272f..ec2bacbe66 100644
--- a/tests/baselines/reference/mappedTypeRelationships.errors.txt
+++ b/tests/baselines/reference/mappedTypeRelationships.errors.txt
@@ -1,39 +1,71 @@
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(12,5): error TS2322: Type 'T[keyof T]' is not assignable to type 'U[keyof T]'.
   Type 'T[string]' is not assignable to type 'U[keyof T]'.
-    Type 'T' is not assignable to type 'U'.
+    Type 'T[string]' is not assignable to type 'U[string]'.
+      Type 'T' is not assignable to type 'U'.
+        Type 'T[keyof T]' is not assignable to type 'U[string]'.
+          Type 'T[string]' is not assignable to type 'U[string]'.
+            Type 'T' is not assignable to type 'U'.
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(17,5): error TS2322: Type 'T[K]' is not assignable to type 'U[K]'.
   Type 'T[string]' is not assignable to type 'U[K]'.
-    Type 'T' is not assignable to type 'U'.
+    Type 'T[string]' is not assignable to type 'U[string]'.
+      Type 'T' is not assignable to type 'U'.
+        Type 'T[K]' is not assignable to type 'U[string]'.
+          Type 'T[string]' is not assignable to type 'U[string]'.
+            Type 'T' is not assignable to type 'U'.
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(21,5): error TS2536: Type 'keyof U' cannot be used to index type 'T'.
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(22,5): error TS2322: Type 'T[keyof U]' is not assignable to type 'U[keyof U]'.
   Type 'T[string]' is not assignable to type 'U[keyof U]'.
-    Type 'T' is not assignable to type 'U'.
+    Type 'T[string]' is not assignable to type 'U[string]'.
+      Type 'T' is not assignable to type 'U'.
+        Type 'T[keyof U]' is not assignable to type 'U[string]'.
+          Type 'T[string]' is not assignable to type 'U[string]'.
+            Type 'T' is not assignable to type 'U'.
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(22,12): error TS2536: Type 'keyof U' cannot be used to index type 'T'.
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(26,5): error TS2536: Type 'K' cannot be used to index type 'T'.
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(27,5): error TS2322: Type 'T[K]' is not assignable to type 'U[K]'.
   Type 'T[string]' is not assignable to type 'U[K]'.
-    Type 'T' is not assignable to type 'U'.
+    Type 'T[string]' is not assignable to type 'U[string]'.
+      Type 'T' is not assignable to type 'U'.
+        Type 'T[K]' is not assignable to type 'U[string]'.
+          Type 'T[string]' is not assignable to type 'U[string]'.
+            Type 'T' is not assignable to type 'U'.
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(27,12): error TS2536: Type 'K' cannot be used to index type 'T'.
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(31,5): error TS2322: Type 'T[keyof T] | undefined' is not assignable to type 'T[keyof T]'.
   Type 'undefined' is not assignable to type 'T[keyof T]'.
+    Type 'undefined' is not assignable to type 'T[string]'.
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(36,5): error TS2322: Type 'T[K] | undefined' is not assignable to type 'T[K]'.
   Type 'undefined' is not assignable to type 'T[K]'.
+    Type 'undefined' is not assignable to type 'T[string]'.
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(41,5): error TS2322: Type 'U[keyof T] | undefined' is not assignable to type 'T[keyof T]'.
   Type 'undefined' is not assignable to type 'T[keyof T]'.
+    Type 'undefined' is not assignable to type 'T[string]'.
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(42,5): error TS2322: Type 'T[keyof T]' is not assignable to type 'U[keyof T] | undefined'.
   Type 'T[string]' is not assignable to type 'U[keyof T] | undefined'.
     Type 'T[string]' is not assignable to type 'U[keyof T]'.
-      Type 'T[keyof T]' is not assignable to type 'U[keyof T]'.
-        Type 'T[string]' is not assignable to type 'U[keyof T]'.
-          Type 'T' is not assignable to type 'U'.
+      Type 'T[string]' is not assignable to type 'U[string]'.
+        Type 'T' is not assignable to type 'U'.
+          Type 'T[keyof T]' is not assignable to type 'U[keyof T]'.
+            Type 'T[string]' is not assignable to type 'U[keyof T]'.
+              Type 'T[string]' is not assignable to type 'U[string]'.
+                Type 'T' is not assignable to type 'U'.
+                  Type 'T[keyof T]' is not assignable to type 'U[string]'.
+                    Type 'T[string]' is not assignable to type 'U[string]'.
+                      Type 'T' is not assignable to type 'U'.
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(46,5): error TS2322: Type 'U[K] | undefined' is not assignable to type 'T[K]'.
   Type 'undefined' is not assignable to type 'T[K]'.
+    Type 'undefined' is not assignable to type 'T[string]'.
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(47,5): error TS2322: Type 'T[K]' is not assignable to type 'U[K] | undefined'.
   Type 'T[string]' is not assignable to type 'U[K] | undefined'.
     Type 'T[string]' is not assignable to type 'U[K]'.
-      Type 'T[K]' is not assignable to type 'U[K]'.
-        Type 'T[string]' is not assignable to type 'U[K]'.
-          Type 'T' is not assignable to type 'U'.
+      Type 'T[string]' is not assignable to type 'U[string]'.
+        Type 'T' is not assignable to type 'U'.
+          Type 'T[K]' is not assignable to type 'U[K]'.
+            Type 'T[string]' is not assignable to type 'U[K]'.
+              Type 'T[string]' is not assignable to type 'U[string]'.
+                Type 'T' is not assignable to type 'U'.
+                  Type 'T[K]' is not assignable to type 'U[string]'.
+                    Type 'T[string]' is not assignable to type 'U[string]'.
+                      Type 'T' is not assignable to type 'U'.
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(52,5): error TS2542: Index signature in type 'Readonly<T>' only permits reading.
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(57,5): error TS2542: Index signature in type 'Readonly<T>' only permits reading.
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(62,5): error TS2542: Index signature in type 'Readonly<U>' only permits reading.
@@ -44,7 +76,11 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(126,5): error TS
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(142,5): error TS2322: Type '{ [P in keyof T]: T[P]; }' is not assignable to type '{ [P in keyof T]: U[P]; }'.
   Type 'T[P]' is not assignable to type 'U[P]'.
     Type 'T[string]' is not assignable to type 'U[P]'.
-      Type 'T' is not assignable to type 'U'.
+      Type 'T[string]' is not assignable to type 'U[string]'.
+        Type 'T' is not assignable to type 'U'.
+          Type 'T[P]' is not assignable to type 'U[string]'.
+            Type 'T[string]' is not assignable to type 'U[string]'.
+              Type 'T' is not assignable to type 'U'.
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(147,5): error TS2322: Type '{ [P in keyof T]: T[P]; }' is not assignable to type '{ [P in keyof U]: U[P]; }'.
   Type 'keyof U' is not assignable to type 'keyof T'.
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(152,5): error TS2322: Type '{ [P in K]: T[P]; }' is not assignable to type '{ [P in keyof T]: T[P]; }'.
@@ -56,7 +92,11 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(162,5): error TS
 tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(167,5): error TS2322: Type '{ [P in K]: T[P]; }' is not assignable to type '{ [P in K]: U[P]; }'.
   Type 'T[P]' is not assignable to type 'U[P]'.
     Type 'T[string]' is not assignable to type 'U[P]'.
-      Type 'T' is not assignable to type 'U'.
+      Type 'T[string]' is not assignable to type 'U[string]'.
+        Type 'T' is not assignable to type 'U'.
+          Type 'T[P]' is not assignable to type 'U[string]'.
+            Type 'T[string]' is not assignable to type 'U[string]'.
+              Type 'T' is not assignable to type 'U'.
 
 
 ==== tests/cases/conformance/types/mapped/mappedTypeRelationships.ts (27 errors) ====
@@ -75,7 +115,11 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(167,5): error TS
         ~~~~
 !!! error TS2322: Type 'T[keyof T]' is not assignable to type 'U[keyof T]'.
 !!! error TS2322:   Type 'T[string]' is not assignable to type 'U[keyof T]'.
-!!! error TS2322:     Type 'T' is not assignable to type 'U'.
+!!! error TS2322:     Type 'T[string]' is not assignable to type 'U[string]'.
+!!! error TS2322:       Type 'T' is not assignable to type 'U'.
+!!! error TS2322:         Type 'T[keyof T]' is not assignable to type 'U[string]'.
+!!! error TS2322:           Type 'T[string]' is not assignable to type 'U[string]'.
+!!! error TS2322:             Type 'T' is not assignable to type 'U'.
     }
     
     function f4<T, U extends T, K extends keyof T>(x: T, y: U, k: K) {
@@ -84,7 +128,11 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(167,5): error TS
         ~~~~
 !!! error TS2322: Type 'T[K]' is not assignable to type 'U[K]'.
 !!! error TS2322:   Type 'T[string]' is not assignable to type 'U[K]'.
-!!! error TS2322:     Type 'T' is not assignable to type 'U'.
+!!! error TS2322:     Type 'T[string]' is not assignable to type 'U[string]'.
+!!! error TS2322:       Type 'T' is not assignable to type 'U'.
+!!! error TS2322:         Type 'T[K]' is not assignable to type 'U[string]'.
+!!! error TS2322:           Type 'T[string]' is not assignable to type 'U[string]'.
+!!! error TS2322:             Type 'T' is not assignable to type 'U'.
     }
     
     function f5<T, U extends T>(x: T, y: U, k: keyof U) {
@@ -95,7 +143,11 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(167,5): error TS
         ~~~~
 !!! error TS2322: Type 'T[keyof U]' is not assignable to type 'U[keyof U]'.
 !!! error TS2322:   Type 'T[string]' is not assignable to type 'U[keyof U]'.
-!!! error TS2322:     Type 'T' is not assignable to type 'U'.
+!!! error TS2322:     Type 'T[string]' is not assignable to type 'U[string]'.
+!!! error TS2322:       Type 'T' is not assignable to type 'U'.
+!!! error TS2322:         Type 'T[keyof U]' is not assignable to type 'U[string]'.
+!!! error TS2322:           Type 'T[string]' is not assignable to type 'U[string]'.
+!!! error TS2322:             Type 'T' is not assignable to type 'U'.
                ~~~~
 !!! error TS2536: Type 'keyof U' cannot be used to index type 'T'.
     }
@@ -108,7 +160,11 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(167,5): error TS
         ~~~~
 !!! error TS2322: Type 'T[K]' is not assignable to type 'U[K]'.
 !!! error TS2322:   Type 'T[string]' is not assignable to type 'U[K]'.
-!!! error TS2322:     Type 'T' is not assignable to type 'U'.
+!!! error TS2322:     Type 'T[string]' is not assignable to type 'U[string]'.
+!!! error TS2322:       Type 'T' is not assignable to type 'U'.
+!!! error TS2322:         Type 'T[K]' is not assignable to type 'U[string]'.
+!!! error TS2322:           Type 'T[string]' is not assignable to type 'U[string]'.
+!!! error TS2322:             Type 'T' is not assignable to type 'U'.
                ~~~~
 !!! error TS2536: Type 'K' cannot be used to index type 'T'.
     }
@@ -118,6 +174,7 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(167,5): error TS
         ~~~~
 !!! error TS2322: Type 'T[keyof T] | undefined' is not assignable to type 'T[keyof T]'.
 !!! error TS2322:   Type 'undefined' is not assignable to type 'T[keyof T]'.
+!!! error TS2322:     Type 'undefined' is not assignable to type 'T[string]'.
         y[k] = x[k];
     }
     
@@ -126,6 +183,7 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(167,5): error TS
         ~~~~
 !!! error TS2322: Type 'T[K] | undefined' is not assignable to type 'T[K]'.
 !!! error TS2322:   Type 'undefined' is not assignable to type 'T[K]'.
+!!! error TS2322:     Type 'undefined' is not assignable to type 'T[string]'.
         y[k] = x[k];
     }
     
@@ -134,14 +192,21 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(167,5): error TS
         ~~~~
 !!! error TS2322: Type 'U[keyof T] | undefined' is not assignable to type 'T[keyof T]'.
 !!! error TS2322:   Type 'undefined' is not assignable to type 'T[keyof T]'.
+!!! error TS2322:     Type 'undefined' is not assignable to type 'T[string]'.
         y[k] = x[k];  // Error
         ~~~~
 !!! error TS2322: Type 'T[keyof T]' is not assignable to type 'U[keyof T] | undefined'.
 !!! error TS2322:   Type 'T[string]' is not assignable to type 'U[keyof T] | undefined'.
 !!! error TS2322:     Type 'T[string]' is not assignable to type 'U[keyof T]'.
-!!! error TS2322:       Type 'T[keyof T]' is not assignable to type 'U[keyof T]'.
-!!! error TS2322:         Type 'T[string]' is not assignable to type 'U[keyof T]'.
-!!! error TS2322:           Type 'T' is not assignable to type 'U'.
+!!! error TS2322:       Type 'T[string]' is not assignable to type 'U[string]'.
+!!! error TS2322:         Type 'T' is not assignable to type 'U'.
+!!! error TS2322:           Type 'T[keyof T]' is not assignable to type 'U[keyof T]'.
+!!! error TS2322:             Type 'T[string]' is not assignable to type 'U[keyof T]'.
+!!! error TS2322:               Type 'T[string]' is not assignable to type 'U[string]'.
+!!! error TS2322:                 Type 'T' is not assignable to type 'U'.
+!!! error TS2322:                   Type 'T[keyof T]' is not assignable to type 'U[string]'.
+!!! error TS2322:                     Type 'T[string]' is not assignable to type 'U[string]'.
+!!! error TS2322:                       Type 'T' is not assignable to type 'U'.
     }
     
     function f13<T, U extends T, K extends keyof T>(x: T, y: Partial<U>, k: K) {
@@ -149,14 +214,21 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(167,5): error TS
         ~~~~
 !!! error TS2322: Type 'U[K] | undefined' is not assignable to type 'T[K]'.
 !!! error TS2322:   Type 'undefined' is not assignable to type 'T[K]'.
+!!! error TS2322:     Type 'undefined' is not assignable to type 'T[string]'.
         y[k] = x[k];  // Error
         ~~~~
 !!! error TS2322: Type 'T[K]' is not assignable to type 'U[K] | undefined'.
 !!! error TS2322:   Type 'T[string]' is not assignable to type 'U[K] | undefined'.
 !!! error TS2322:     Type 'T[string]' is not assignable to type 'U[K]'.
-!!! error TS2322:       Type 'T[K]' is not assignable to type 'U[K]'.
-!!! error TS2322:         Type 'T[string]' is not assignable to type 'U[K]'.
-!!! error TS2322:           Type 'T' is not assignable to type 'U'.
+!!! error TS2322:       Type 'T[string]' is not assignable to type 'U[string]'.
+!!! error TS2322:         Type 'T' is not assignable to type 'U'.
+!!! error TS2322:           Type 'T[K]' is not assignable to type 'U[K]'.
+!!! error TS2322:             Type 'T[string]' is not assignable to type 'U[K]'.
+!!! error TS2322:               Type 'T[string]' is not assignable to type 'U[string]'.
+!!! error TS2322:                 Type 'T' is not assignable to type 'U'.
+!!! error TS2322:                   Type 'T[K]' is not assignable to type 'U[string]'.
+!!! error TS2322:                     Type 'T[string]' is not assignable to type 'U[string]'.
+!!! error TS2322:                       Type 'T' is not assignable to type 'U'.
     }
     
     function f20<T>(x: T, y: Readonly<T>, k: keyof T) {
@@ -270,7 +342,11 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(167,5): error TS
 !!! error TS2322: Type '{ [P in keyof T]: T[P]; }' is not assignable to type '{ [P in keyof T]: U[P]; }'.
 !!! error TS2322:   Type 'T[P]' is not assignable to type 'U[P]'.
 !!! error TS2322:     Type 'T[string]' is not assignable to type 'U[P]'.
-!!! error TS2322:       Type 'T' is not assignable to type 'U'.
+!!! error TS2322:       Type 'T[string]' is not assignable to type 'U[string]'.
+!!! error TS2322:         Type 'T' is not assignable to type 'U'.
+!!! error TS2322:           Type 'T[P]' is not assignable to type 'U[string]'.
+!!! error TS2322:             Type 'T[string]' is not assignable to type 'U[string]'.
+!!! error TS2322:               Type 'T' is not assignable to type 'U'.
     }
     
     function f72<T, U extends T>(x: { [P in keyof T]: T[P] }, y: { [P in keyof U]: U[P] }) {
@@ -312,6 +388,10 @@ tests/cases/conformance/types/mapped/mappedTypeRelationships.ts(167,5): error TS
 !!! error TS2322: Type '{ [P in K]: T[P]; }' is not assignable to type '{ [P in K]: U[P]; }'.
 !!! error TS2322:   Type 'T[P]' is not assignable to type 'U[P]'.
 !!! error TS2322:     Type 'T[string]' is not assignable to type 'U[P]'.
-!!! error TS2322:       Type 'T' is not assignable to type 'U'.
+!!! error TS2322:       Type 'T[string]' is not assignable to type 'U[string]'.
+!!! error TS2322:         Type 'T' is not assignable to type 'U'.
+!!! error TS2322:           Type 'T[P]' is not assignable to type 'U[string]'.
+!!! error TS2322:             Type 'T[string]' is not assignable to type 'U[string]'.
+!!! error TS2322:               Type 'T' is not assignable to type 'U'.
     }
     
\ No newline at end of file
diff --git a/tests/cases/compiler/indexedAccessRelation.ts b/tests/cases/compiler/indexedAccessRelation.ts
new file mode 100644
index 0000000000..ccfcd559e2
--- /dev/null
+++ b/tests/cases/compiler/indexedAccessRelation.ts
@@ -0,0 +1,18 @@
+// Repro from #14723
+
+class Component<S> {
+    setState<K extends keyof S>(state: Pick<S, K>) {}
+}
+
+export interface State<T> {
+    a?: T;
+}
+
+class Foo {}
+
+class Comp<T extends Foo, S> extends Component<S & State<T>>
+{
+    foo(a: T) {
+        this.setState({ a: a });
+    }
+}