Avoid pulling on setter type when only getter type is needed to break circularity (#47818)

Author: andrewbranch

src/compiler/checker.ts

@@ -9511,11 +9511,12 @@ namespace ts {
             const getter = getDeclarationOfKind<AccessorDeclaration>(symbol, SyntaxKind.GetAccessor);
             const setter = getDeclarationOfKind<AccessorDeclaration>(symbol, SyntaxKind.SetAccessor);
 
-            const setterType = getAnnotatedAccessorType(setter);
-
             // For write operations, prioritize type annotations on the setter
-            if (writing && setterType) {
-                return instantiateTypeIfNeeded(setterType, symbol);
+            if (writing) {
+                const setterType = getAnnotatedAccessorType(setter);
+                if (setterType) {
+                    return instantiateTypeIfNeeded(setterType, symbol);
+                }
             }
             // Else defer to the getter type
 
@@ -9533,6 +9534,7 @@ namespace ts {
             }
 
             // If the user didn't specify a return type, try to use the set-accessor's parameter type.
+            const setterType = getAnnotatedAccessorType(setter);
             if (setterType) {
                 return setterType;
             }

tests/baselines/reference/mappedTypeCircularReferenceInAccessor.js

@@ -0,0 +1,16 @@
+//// [mappedTypeCircularReferenceInAccessor.ts]
+interface User {
+  firstName: string,
+  level: number,
+  get bestFriend(): User
+  set bestFriend(user: SerializablePartial<User>)
+}
+
+type FilteredKeys<T> = { [K in keyof T]: T[K] extends number ? K : T[K] extends string ? K : T[K] extends boolean ? K : never }[keyof T];
+
+type SerializablePartial<T> = {
+  [K in FilteredKeys<T>]: T[K]
+};
+
+
+//// [mappedTypeCircularReferenceInAccessor.js]

tests/baselines/reference/mappedTypeCircularReferenceInAccessor.symbols

@@ -0,0 +1,50 @@
+=== tests/cases/compiler/mappedTypeCircularReferenceInAccessor.ts ===
+interface User {
+>User : Symbol(User, Decl(mappedTypeCircularReferenceInAccessor.ts, 0, 0))
+
+  firstName: string,
+>firstName : Symbol(User.firstName, Decl(mappedTypeCircularReferenceInAccessor.ts, 0, 16))
+
+  level: number,
+>level : Symbol(User.level, Decl(mappedTypeCircularReferenceInAccessor.ts, 1, 20))
+
+  get bestFriend(): User
+>bestFriend : Symbol(User.bestFriend, Decl(mappedTypeCircularReferenceInAccessor.ts, 2, 16), Decl(mappedTypeCircularReferenceInAccessor.ts, 3, 24))
+>User : Symbol(User, Decl(mappedTypeCircularReferenceInAccessor.ts, 0, 0))
+
+  set bestFriend(user: SerializablePartial<User>)
+>bestFriend : Symbol(User.bestFriend, Decl(mappedTypeCircularReferenceInAccessor.ts, 2, 16), Decl(mappedTypeCircularReferenceInAccessor.ts, 3, 24))
+>user : Symbol(user, Decl(mappedTypeCircularReferenceInAccessor.ts, 4, 17))
+>SerializablePartial : Symbol(SerializablePartial, Decl(mappedTypeCircularReferenceInAccessor.ts, 7, 137))
+>User : Symbol(User, Decl(mappedTypeCircularReferenceInAccessor.ts, 0, 0))
+}
+
+type FilteredKeys<T> = { [K in keyof T]: T[K] extends number ? K : T[K] extends string ? K : T[K] extends boolean ? K : never }[keyof T];
+>FilteredKeys : Symbol(FilteredKeys, Decl(mappedTypeCircularReferenceInAccessor.ts, 5, 1))
+>T : Symbol(T, Decl(mappedTypeCircularReferenceInAccessor.ts, 7, 18))
+>K : Symbol(K, Decl(mappedTypeCircularReferenceInAccessor.ts, 7, 26))
+>T : Symbol(T, Decl(mappedTypeCircularReferenceInAccessor.ts, 7, 18))
+>T : Symbol(T, Decl(mappedTypeCircularReferenceInAccessor.ts, 7, 18))
+>K : Symbol(K, Decl(mappedTypeCircularReferenceInAccessor.ts, 7, 26))
+>K : Symbol(K, Decl(mappedTypeCircularReferenceInAccessor.ts, 7, 26))
+>T : Symbol(T, Decl(mappedTypeCircularReferenceInAccessor.ts, 7, 18))
+>K : Symbol(K, Decl(mappedTypeCircularReferenceInAccessor.ts, 7, 26))
+>K : Symbol(K, Decl(mappedTypeCircularReferenceInAccessor.ts, 7, 26))
+>T : Symbol(T, Decl(mappedTypeCircularReferenceInAccessor.ts, 7, 18))
+>K : Symbol(K, Decl(mappedTypeCircularReferenceInAccessor.ts, 7, 26))
+>K : Symbol(K, Decl(mappedTypeCircularReferenceInAccessor.ts, 7, 26))
+>T : Symbol(T, Decl(mappedTypeCircularReferenceInAccessor.ts, 7, 18))
+
+type SerializablePartial<T> = {
+>SerializablePartial : Symbol(SerializablePartial, Decl(mappedTypeCircularReferenceInAccessor.ts, 7, 137))
+>T : Symbol(T, Decl(mappedTypeCircularReferenceInAccessor.ts, 9, 25))
+
+  [K in FilteredKeys<T>]: T[K]
+>K : Symbol(K, Decl(mappedTypeCircularReferenceInAccessor.ts, 10, 3))
+>FilteredKeys : Symbol(FilteredKeys, Decl(mappedTypeCircularReferenceInAccessor.ts, 5, 1))
+>T : Symbol(T, Decl(mappedTypeCircularReferenceInAccessor.ts, 9, 25))
+>T : Symbol(T, Decl(mappedTypeCircularReferenceInAccessor.ts, 9, 25))
+>K : Symbol(K, Decl(mappedTypeCircularReferenceInAccessor.ts, 10, 3))
+
+};
+

tests/baselines/reference/mappedTypeCircularReferenceInAccessor.types

@@ -0,0 +1,25 @@
+=== tests/cases/compiler/mappedTypeCircularReferenceInAccessor.ts ===
+interface User {
+  firstName: string,
+>firstName : string
+
+  level: number,
+>level : number
+
+  get bestFriend(): User
+>bestFriend : User
+
+  set bestFriend(user: SerializablePartial<User>)
+>bestFriend : User
+>user : SerializablePartial<User>
+}
+
+type FilteredKeys<T> = { [K in keyof T]: T[K] extends number ? K : T[K] extends string ? K : T[K] extends boolean ? K : never }[keyof T];
+>FilteredKeys : FilteredKeys<T>
+
+type SerializablePartial<T> = {
+>SerializablePartial : SerializablePartial<T>
+
+  [K in FilteredKeys<T>]: T[K]
+};
+

tests/cases/compiler/mappedTypeCircularReferenceInAccessor.ts

@@ -0,0 +1,12 @@
+interface User {
+  firstName: string,
+  level: number,
+  get bestFriend(): User
+  set bestFriend(user: SerializablePartial<User>)
+}
+
+type FilteredKeys<T> = { [K in keyof T]: T[K] extends number ? K : T[K] extends string ? K : T[K] extends boolean ? K : never }[keyof T];
+
+type SerializablePartial<T> = {
+  [K in FilteredKeys<T>]: T[K]
+};