diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 480f7189fce31..9bcfa8d76a664 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -23701,8 +23701,8 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                 // Check if source type `S` is related to target type `{ [P in Q]: T }` or `{ [P in Q as R]: T}`.
                 const keysRemapped = !!target.declaration.nameType;
                 const templateType = getTemplateTypeFromMappedType(target);
-                const modifiers = getMappedTypeModifiers(target);
-                if (!(modifiers & MappedTypeModifiers.ExcludeOptional)) {
+                const combinedOptionality = getCombinedMappedTypeOptionality(target);
+                if (combinedOptionality !== -1) {
                     // If the mapped type has shape `{ [P in Q]: T[P] }`,
                     // source `S` is related to target if `T` = `S`, i.e. `S` is related to `{ [P in Q]: S[P] }`.
                     if (
@@ -23717,7 +23717,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                         const targetKeys = keysRemapped ? getNameTypeFromMappedType(target)! : getConstraintTypeFromMappedType(target);
                         // Type of the keys of source type `S`, i.e. `keyof S`.
                         const sourceKeys = getIndexType(source, IndexFlags.NoIndexSignatures);
-                        const includeOptional = modifiers & MappedTypeModifiers.IncludeOptional;
+                        const includeOptional = combinedOptionality === 1;
                         const filteredByApplicability = includeOptional ? intersectTypes(targetKeys, sourceKeys) : undefined;
                         // A source type `S` is related to a target type `{ [P in Q]: T }` if `Q` is related to `keyof S` and `S[Q]` is related to `T`.
                         // A source type `S` is related to a target type `{ [P in Q as R]: T }` if `R` is related to `keyof S` and `S[R]` is related to `T.
@@ -23734,10 +23734,8 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                             // Fastpath: When the template type has the form `Obj[P]` where `P` is the mapped type parameter, directly compare source `S` with `Obj`
                             // to avoid creating the (potentially very large) number of new intermediate types made by manufacturing `S[P]`.
                             const nonNullComponent = extractTypesOfKind(templateType, ~TypeFlags.Nullable);
-                            if (!keysRemapped && nonNullComponent.flags & TypeFlags.IndexedAccess && (nonNullComponent as IndexedAccessType).indexType === typeParameter) {
-                                if (result = isRelatedTo(source, (nonNullComponent as IndexedAccessType).objectType, RecursionFlags.Target, reportErrors)) {
-                                    return result;
-                                }
+                            if (!keysRemapped && nonNullComponent.flags & TypeFlags.IndexedAccess && (nonNullComponent as IndexedAccessType).indexType === typeParameter && (result = isRelatedTo(source, (nonNullComponent as IndexedAccessType).objectType, RecursionFlags.Target, reportErrors))) {
+                                return result;
                             }
                             else {
                                 // We need to compare the type of a property on the source type `S` to the type of the same property on the target type,
diff --git a/tests/baselines/reference/mappedTypeRelationships2.errors.txt b/tests/baselines/reference/mappedTypeRelationships2.errors.txt
new file mode 100644
index 0000000000000..c82474fedece6
--- /dev/null
+++ b/tests/baselines/reference/mappedTypeRelationships2.errors.txt
@@ -0,0 +1,40 @@
+mappedTypeRelationships2.ts(21,38): error TS2344: Type 'ABC' does not satisfy the constraint 'WithNumber<Record<keyof T, any>>'.
+
+
+==== mappedTypeRelationships2.ts (1 errors) ====
+    // https://github.com/microsoft/TypeScript/issues/62717
+    
+    type Alias1<T extends object, U extends { [K in keyof T]?: any }> = U;
+    type Alias2<T extends object, U extends Partial<Record<keyof T, any>>> = U;
+    
+    type AB = { a: string; b: string };
+    type B = { b: string };
+    
+    type Test1 = Alias1<AB, B>; // ok
+    type Test2 = Alias2<AB, B>; // ok
+    
+    type Test3<T extends AB> = Alias1<T, B>; // ok
+    type Test4<T extends AB> = Alias2<T, B>; // ok
+    
+    type WithNumber<T> = { [K in keyof T]: T[K] | number };
+    type Alias3<T extends object, U extends WithNumber<Record<keyof T, any>>> = U;
+    
+    type ABC = { a: string; b: string; c: string };
+    
+    type Test5 = Alias3<AB, ABC>; // ok
+    type Test6<T extends AB> = Alias3<T, ABC>; // error
+                                         ~~~
+!!! error TS2344: Type 'ABC' does not satisfy the constraint 'WithNumber<Record<keyof T, any>>'.
+    
+    type Alias4<T extends object, U extends WithNumber<Partial<Record<keyof T, any>>>> = U;
+    
+    type Test7 = Alias4<AB, ABC>; // ok
+    type Test8<T extends AB> = Alias4<T, ABC>; // ok
+    
+    type Alias5<T extends object, U extends Partial<WithNumber<Record<keyof T, any>>>> = U;
+    
+    type Test9 = Alias5<AB, ABC>; // ok
+    type Test10<T extends AB> = Alias5<T, ABC>; // ok
+    
+    export {};
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/mappedTypeRelationships2.symbols b/tests/baselines/reference/mappedTypeRelationships2.symbols
new file mode 100644
index 0000000000000..d0328500a2c01
--- /dev/null
+++ b/tests/baselines/reference/mappedTypeRelationships2.symbols
@@ -0,0 +1,146 @@
+//// [tests/cases/conformance/types/mapped/mappedTypeRelationships2.ts] ////
+
+=== mappedTypeRelationships2.ts ===
+// https://github.com/microsoft/TypeScript/issues/62717
+
+type Alias1<T extends object, U extends { [K in keyof T]?: any }> = U;
+>Alias1 : Symbol(Alias1, Decl(mappedTypeRelationships2.ts, 0, 0))
+>T : Symbol(T, Decl(mappedTypeRelationships2.ts, 2, 12))
+>U : Symbol(U, Decl(mappedTypeRelationships2.ts, 2, 29))
+>K : Symbol(K, Decl(mappedTypeRelationships2.ts, 2, 43))
+>T : Symbol(T, Decl(mappedTypeRelationships2.ts, 2, 12))
+>U : Symbol(U, Decl(mappedTypeRelationships2.ts, 2, 29))
+
+type Alias2<T extends object, U extends Partial<Record<keyof T, any>>> = U;
+>Alias2 : Symbol(Alias2, Decl(mappedTypeRelationships2.ts, 2, 70))
+>T : Symbol(T, Decl(mappedTypeRelationships2.ts, 3, 12))
+>U : Symbol(U, Decl(mappedTypeRelationships2.ts, 3, 29))
+>Partial : Symbol(Partial, Decl(lib.es5.d.ts, --, --))
+>Record : Symbol(Record, Decl(lib.es5.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypeRelationships2.ts, 3, 12))
+>U : Symbol(U, Decl(mappedTypeRelationships2.ts, 3, 29))
+
+type AB = { a: string; b: string };
+>AB : Symbol(AB, Decl(mappedTypeRelationships2.ts, 3, 75))
+>a : Symbol(a, Decl(mappedTypeRelationships2.ts, 5, 11))
+>b : Symbol(b, Decl(mappedTypeRelationships2.ts, 5, 22))
+
+type B = { b: string };
+>B : Symbol(B, Decl(mappedTypeRelationships2.ts, 5, 35))
+>b : Symbol(b, Decl(mappedTypeRelationships2.ts, 6, 10))
+
+type Test1 = Alias1<AB, B>; // ok
+>Test1 : Symbol(Test1, Decl(mappedTypeRelationships2.ts, 6, 23))
+>Alias1 : Symbol(Alias1, Decl(mappedTypeRelationships2.ts, 0, 0))
+>AB : Symbol(AB, Decl(mappedTypeRelationships2.ts, 3, 75))
+>B : Symbol(B, Decl(mappedTypeRelationships2.ts, 5, 35))
+
+type Test2 = Alias2<AB, B>; // ok
+>Test2 : Symbol(Test2, Decl(mappedTypeRelationships2.ts, 8, 27))
+>Alias2 : Symbol(Alias2, Decl(mappedTypeRelationships2.ts, 2, 70))
+>AB : Symbol(AB, Decl(mappedTypeRelationships2.ts, 3, 75))
+>B : Symbol(B, Decl(mappedTypeRelationships2.ts, 5, 35))
+
+type Test3<T extends AB> = Alias1<T, B>; // ok
+>Test3 : Symbol(Test3, Decl(mappedTypeRelationships2.ts, 9, 27))
+>T : Symbol(T, Decl(mappedTypeRelationships2.ts, 11, 11))
+>AB : Symbol(AB, Decl(mappedTypeRelationships2.ts, 3, 75))
+>Alias1 : Symbol(Alias1, Decl(mappedTypeRelationships2.ts, 0, 0))
+>T : Symbol(T, Decl(mappedTypeRelationships2.ts, 11, 11))
+>B : Symbol(B, Decl(mappedTypeRelationships2.ts, 5, 35))
+
+type Test4<T extends AB> = Alias2<T, B>; // ok
+>Test4 : Symbol(Test4, Decl(mappedTypeRelationships2.ts, 11, 40))
+>T : Symbol(T, Decl(mappedTypeRelationships2.ts, 12, 11))
+>AB : Symbol(AB, Decl(mappedTypeRelationships2.ts, 3, 75))
+>Alias2 : Symbol(Alias2, Decl(mappedTypeRelationships2.ts, 2, 70))
+>T : Symbol(T, Decl(mappedTypeRelationships2.ts, 12, 11))
+>B : Symbol(B, Decl(mappedTypeRelationships2.ts, 5, 35))
+
+type WithNumber<T> = { [K in keyof T]: T[K] | number };
+>WithNumber : Symbol(WithNumber, Decl(mappedTypeRelationships2.ts, 12, 40))
+>T : Symbol(T, Decl(mappedTypeRelationships2.ts, 14, 16))
+>K : Symbol(K, Decl(mappedTypeRelationships2.ts, 14, 24))
+>T : Symbol(T, Decl(mappedTypeRelationships2.ts, 14, 16))
+>T : Symbol(T, Decl(mappedTypeRelationships2.ts, 14, 16))
+>K : Symbol(K, Decl(mappedTypeRelationships2.ts, 14, 24))
+
+type Alias3<T extends object, U extends WithNumber<Record<keyof T, any>>> = U;
+>Alias3 : Symbol(Alias3, Decl(mappedTypeRelationships2.ts, 14, 55))
+>T : Symbol(T, Decl(mappedTypeRelationships2.ts, 15, 12))
+>U : Symbol(U, Decl(mappedTypeRelationships2.ts, 15, 29))
+>WithNumber : Symbol(WithNumber, Decl(mappedTypeRelationships2.ts, 12, 40))
+>Record : Symbol(Record, Decl(lib.es5.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypeRelationships2.ts, 15, 12))
+>U : Symbol(U, Decl(mappedTypeRelationships2.ts, 15, 29))
+
+type ABC = { a: string; b: string; c: string };
+>ABC : Symbol(ABC, Decl(mappedTypeRelationships2.ts, 15, 78))
+>a : Symbol(a, Decl(mappedTypeRelationships2.ts, 17, 12))
+>b : Symbol(b, Decl(mappedTypeRelationships2.ts, 17, 23))
+>c : Symbol(c, Decl(mappedTypeRelationships2.ts, 17, 34))
+
+type Test5 = Alias3<AB, ABC>; // ok
+>Test5 : Symbol(Test5, Decl(mappedTypeRelationships2.ts, 17, 47))
+>Alias3 : Symbol(Alias3, Decl(mappedTypeRelationships2.ts, 14, 55))
+>AB : Symbol(AB, Decl(mappedTypeRelationships2.ts, 3, 75))
+>ABC : Symbol(ABC, Decl(mappedTypeRelationships2.ts, 15, 78))
+
+type Test6<T extends AB> = Alias3<T, ABC>; // error
+>Test6 : Symbol(Test6, Decl(mappedTypeRelationships2.ts, 19, 29))
+>T : Symbol(T, Decl(mappedTypeRelationships2.ts, 20, 11))
+>AB : Symbol(AB, Decl(mappedTypeRelationships2.ts, 3, 75))
+>Alias3 : Symbol(Alias3, Decl(mappedTypeRelationships2.ts, 14, 55))
+>T : Symbol(T, Decl(mappedTypeRelationships2.ts, 20, 11))
+>ABC : Symbol(ABC, Decl(mappedTypeRelationships2.ts, 15, 78))
+
+type Alias4<T extends object, U extends WithNumber<Partial<Record<keyof T, any>>>> = U;
+>Alias4 : Symbol(Alias4, Decl(mappedTypeRelationships2.ts, 20, 42))
+>T : Symbol(T, Decl(mappedTypeRelationships2.ts, 22, 12))
+>U : Symbol(U, Decl(mappedTypeRelationships2.ts, 22, 29))
+>WithNumber : Symbol(WithNumber, Decl(mappedTypeRelationships2.ts, 12, 40))
+>Partial : Symbol(Partial, Decl(lib.es5.d.ts, --, --))
+>Record : Symbol(Record, Decl(lib.es5.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypeRelationships2.ts, 22, 12))
+>U : Symbol(U, Decl(mappedTypeRelationships2.ts, 22, 29))
+
+type Test7 = Alias4<AB, ABC>; // ok
+>Test7 : Symbol(Test7, Decl(mappedTypeRelationships2.ts, 22, 87))
+>Alias4 : Symbol(Alias4, Decl(mappedTypeRelationships2.ts, 20, 42))
+>AB : Symbol(AB, Decl(mappedTypeRelationships2.ts, 3, 75))
+>ABC : Symbol(ABC, Decl(mappedTypeRelationships2.ts, 15, 78))
+
+type Test8<T extends AB> = Alias4<T, ABC>; // ok
+>Test8 : Symbol(Test8, Decl(mappedTypeRelationships2.ts, 24, 29))
+>T : Symbol(T, Decl(mappedTypeRelationships2.ts, 25, 11))
+>AB : Symbol(AB, Decl(mappedTypeRelationships2.ts, 3, 75))
+>Alias4 : Symbol(Alias4, Decl(mappedTypeRelationships2.ts, 20, 42))
+>T : Symbol(T, Decl(mappedTypeRelationships2.ts, 25, 11))
+>ABC : Symbol(ABC, Decl(mappedTypeRelationships2.ts, 15, 78))
+
+type Alias5<T extends object, U extends Partial<WithNumber<Record<keyof T, any>>>> = U;
+>Alias5 : Symbol(Alias5, Decl(mappedTypeRelationships2.ts, 25, 42))
+>T : Symbol(T, Decl(mappedTypeRelationships2.ts, 27, 12))
+>U : Symbol(U, Decl(mappedTypeRelationships2.ts, 27, 29))
+>Partial : Symbol(Partial, Decl(lib.es5.d.ts, --, --))
+>WithNumber : Symbol(WithNumber, Decl(mappedTypeRelationships2.ts, 12, 40))
+>Record : Symbol(Record, Decl(lib.es5.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypeRelationships2.ts, 27, 12))
+>U : Symbol(U, Decl(mappedTypeRelationships2.ts, 27, 29))
+
+type Test9 = Alias5<AB, ABC>; // ok
+>Test9 : Symbol(Test9, Decl(mappedTypeRelationships2.ts, 27, 87))
+>Alias5 : Symbol(Alias5, Decl(mappedTypeRelationships2.ts, 25, 42))
+>AB : Symbol(AB, Decl(mappedTypeRelationships2.ts, 3, 75))
+>ABC : Symbol(ABC, Decl(mappedTypeRelationships2.ts, 15, 78))
+
+type Test10<T extends AB> = Alias5<T, ABC>; // ok
+>Test10 : Symbol(Test10, Decl(mappedTypeRelationships2.ts, 29, 29))
+>T : Symbol(T, Decl(mappedTypeRelationships2.ts, 30, 12))
+>AB : Symbol(AB, Decl(mappedTypeRelationships2.ts, 3, 75))
+>Alias5 : Symbol(Alias5, Decl(mappedTypeRelationships2.ts, 25, 42))
+>T : Symbol(T, Decl(mappedTypeRelationships2.ts, 30, 12))
+>ABC : Symbol(ABC, Decl(mappedTypeRelationships2.ts, 15, 78))
+
+export {};
+
diff --git a/tests/baselines/reference/mappedTypeRelationships2.types b/tests/baselines/reference/mappedTypeRelationships2.types
new file mode 100644
index 0000000000000..667642744f899
--- /dev/null
+++ b/tests/baselines/reference/mappedTypeRelationships2.types
@@ -0,0 +1,95 @@
+//// [tests/cases/conformance/types/mapped/mappedTypeRelationships2.ts] ////
+
+=== mappedTypeRelationships2.ts ===
+// https://github.com/microsoft/TypeScript/issues/62717
+
+type Alias1<T extends object, U extends { [K in keyof T]?: any }> = U;
+>Alias1 : U
+>       : ^
+
+type Alias2<T extends object, U extends Partial<Record<keyof T, any>>> = U;
+>Alias2 : U
+>       : ^
+
+type AB = { a: string; b: string };
+>AB : AB
+>   : ^^
+>a : string
+>  : ^^^^^^
+>b : string
+>  : ^^^^^^
+
+type B = { b: string };
+>B : B
+>  : ^
+>b : string
+>  : ^^^^^^
+
+type Test1 = Alias1<AB, B>; // ok
+>Test1 : B
+>      : ^
+
+type Test2 = Alias2<AB, B>; // ok
+>Test2 : B
+>      : ^
+
+type Test3<T extends AB> = Alias1<T, B>; // ok
+>Test3 : B
+>      : ^
+
+type Test4<T extends AB> = Alias2<T, B>; // ok
+>Test4 : B
+>      : ^
+
+type WithNumber<T> = { [K in keyof T]: T[K] | number };
+>WithNumber : WithNumber<T>
+>           : ^^^^^^^^^^^^^
+
+type Alias3<T extends object, U extends WithNumber<Record<keyof T, any>>> = U;
+>Alias3 : U
+>       : ^
+
+type ABC = { a: string; b: string; c: string };
+>ABC : ABC
+>    : ^^^
+>a : string
+>  : ^^^^^^
+>b : string
+>  : ^^^^^^
+>c : string
+>  : ^^^^^^
+
+type Test5 = Alias3<AB, ABC>; // ok
+>Test5 : ABC
+>      : ^^^
+
+type Test6<T extends AB> = Alias3<T, ABC>; // error
+>Test6 : ABC
+>      : ^^^
+
+type Alias4<T extends object, U extends WithNumber<Partial<Record<keyof T, any>>>> = U;
+>Alias4 : U
+>       : ^
+
+type Test7 = Alias4<AB, ABC>; // ok
+>Test7 : ABC
+>      : ^^^
+
+type Test8<T extends AB> = Alias4<T, ABC>; // ok
+>Test8 : ABC
+>      : ^^^
+
+type Alias5<T extends object, U extends Partial<WithNumber<Record<keyof T, any>>>> = U;
+>Alias5 : U
+>       : ^
+
+type Test9 = Alias5<AB, ABC>; // ok
+>Test9 : ABC
+>      : ^^^
+
+type Test10<T extends AB> = Alias5<T, ABC>; // ok
+>Test10 : ABC
+>       : ^^^
+
+export {};
+
diff --git a/tests/cases/conformance/types/mapped/mappedTypeRelationships2.ts b/tests/cases/conformance/types/mapped/mappedTypeRelationships2.ts
new file mode 100644
index 0000000000000..415c7870918fa
--- /dev/null
+++ b/tests/cases/conformance/types/mapped/mappedTypeRelationships2.ts
@@ -0,0 +1,36 @@
+// @strict: true
+// @noEmit: true
+
+// https://github.com/microsoft/TypeScript/issues/62717
+
+type Alias1<T extends object, U extends { [K in keyof T]?: any }> = U;
+type Alias2<T extends object, U extends Partial<Record<keyof T, any>>> = U;
+
+type AB = { a: string; b: string };
+type B = { b: string };
+
+type Test1 = Alias1<AB, B>; // ok
+type Test2 = Alias2<AB, B>; // ok
+
+type Test3<T extends AB> = Alias1<T, B>; // ok
+type Test4<T extends AB> = Alias2<T, B>; // ok
+
+type WithNumber<T> = { [K in keyof T]: T[K] | number };
+type Alias3<T extends object, U extends WithNumber<Record<keyof T, any>>> = U;
+
+type ABC = { a: string; b: string; c: string };
+
+type Test5 = Alias3<AB, ABC>; // ok
+type Test6<T extends AB> = Alias3<T, ABC>; // error
+
+type Alias4<T extends object, U extends WithNumber<Partial<Record<keyof T, any>>>> = U;
+
+type Test7 = Alias4<AB, ABC>; // ok
+type Test8<T extends AB> = Alias4<T, ABC>; // ok
+
+type Alias5<T extends object, U extends Partial<WithNumber<Record<keyof T, any>>>> = U;
+
+type Test9 = Alias5<AB, ABC>; // ok
+type Test10<T extends AB> = Alias5<T, ABC>; // ok
+
+export {};