Speculative fix for array compat issue (ignore)

src/compiler/checker.ts

@@ -25300,6 +25300,11 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
     function getRecursionIdentity(type: Type): object {
         // Object and array literals are known not to contain recursive references and don't need a recursion identity.
         if (type.flags & TypeFlags.Object && !isObjectOrArrayLiteralType(type)) {
+            if (isArrayType(type)) {
+                // Array wrappers are common and finite in non-recursive object graphs; track recursion identity through
+                // the element type instead of the shared global Array symbol to avoid false positives in deep nesting.
+                return getRecursionIdentity(getTypeArguments(type)[0]);
+            }
             if (getObjectFlags(type) & ObjectFlags.Reference && (type as TypeReference).node) {
                 // Deferred type references are tracked through their associated AST node. This gives us finer
                 // granularity than using their associated target because each manifest type reference has a

tests/baselines/reference/issue52912.errors.txt

@@ -0,0 +1,77 @@
+issue52912.ts(18,7): error TS2322: Type 'Source1' is not assignable to type 'Target1'.
+  Types of property 'array' are incompatible.
+    Type 'Source2[]' is not assignable to type 'Target2[]'.
+      Type 'Source2' is not assignable to type 'Target2'.
+        Types of property 'array' are incompatible.
+          Type 'Source3[]' is not assignable to type 'Target3[]'.
+            Type 'Source3' is not assignable to type 'Target3'.
+              Types of property 'array' are incompatible.
+                Type 'Source4[]' is not assignable to type 'Target4[]'.
+                  Property 'someNewProperty' is missing in type 'Source4' but required in type 'Target4'.
+issue52912.ts(19,7): error TS2322: Type 'Source2' is not assignable to type 'Target2'.
+  Types of property 'array' are incompatible.
+    Type 'Source3[]' is not assignable to type 'Target3[]'.
+      Type 'Source3' is not assignable to type 'Target3'.
+        Types of property 'array' are incompatible.
+          Type 'Source4[]' is not assignable to type 'Target4[]'.
+            Property 'someNewProperty' is missing in type 'Source4' but required in type 'Target4'.
+issue52912.ts(20,7): error TS2322: Type 'Source3' is not assignable to type 'Target3'.
+  Types of property 'array' are incompatible.
+    Type 'Source4[]' is not assignable to type 'Target4[]'.
+      Property 'someNewProperty' is missing in type 'Source4' but required in type 'Target4'.
+issue52912.ts(21,7): error TS2741: Property 'someNewProperty' is missing in type 'Source4' but required in type 'Target4'.
+
+
+==== issue52912.ts (4 errors) ====
+    // Repro from #52912
+
+    type Source1 = { array: Source2[] };
+    type Source2 = { array: Source3[] };
+    type Source3 = { array: Source4[] };
+    type Source4 = {};
+
+    type Target1 = { array: Target2[] };
+    type Target2 = { array: Target3[] };
+    type Target3 = { array: Target4[] };
+    type Target4 = { someNewProperty: string };
+
+    declare const source1: Source1;
+    declare const source2: Source2;
+    declare const source3: Source3;
+    declare const source4: Source4;
+
+    const target1: Target1 = source1; // Error
+          ~~~~~~~
+!!! error TS2322: Type 'Source1' is not assignable to type 'Target1'.
+!!! error TS2322:   Types of property 'array' are incompatible.
+!!! error TS2322:     Type 'Source2[]' is not assignable to type 'Target2[]'.
+!!! error TS2322:       Type 'Source2' is not assignable to type 'Target2'.
+!!! error TS2322:         Types of property 'array' are incompatible.
+!!! error TS2322:           Type 'Source3[]' is not assignable to type 'Target3[]'.
+!!! error TS2322:             Type 'Source3' is not assignable to type 'Target3'.
+!!! error TS2322:               Types of property 'array' are incompatible.
+!!! error TS2322:                 Type 'Source4[]' is not assignable to type 'Target4[]'.
+!!! error TS2322:                   Property 'someNewProperty' is missing in type 'Source4' but required in type 'Target4'.
+!!! related TS2728 issue52912.ts:11:18: 'someNewProperty' is declared here.
+    const target2: Target2 = source2; // Error
+          ~~~~~~~
+!!! error TS2322: Type 'Source2' is not assignable to type 'Target2'.
+!!! error TS2322:   Types of property 'array' are incompatible.
+!!! error TS2322:     Type 'Source3[]' is not assignable to type 'Target3[]'.
+!!! error TS2322:       Type 'Source3' is not assignable to type 'Target3'.
+!!! error TS2322:         Types of property 'array' are incompatible.
+!!! error TS2322:           Type 'Source4[]' is not assignable to type 'Target4[]'.
+!!! error TS2322:             Property 'someNewProperty' is missing in type 'Source4' but required in type 'Target4'.
+!!! related TS2728 issue52912.ts:11:18: 'someNewProperty' is declared here.
+    const target3: Target3 = source3; // Error
+          ~~~~~~~
+!!! error TS2322: Type 'Source3' is not assignable to type 'Target3'.
+!!! error TS2322:   Types of property 'array' are incompatible.
+!!! error TS2322:     Type 'Source4[]' is not assignable to type 'Target4[]'.
+!!! error TS2322:       Property 'someNewProperty' is missing in type 'Source4' but required in type 'Target4'.
+!!! related TS2728 issue52912.ts:11:18: 'someNewProperty' is declared here.
+    const target4: Target4 = source4; // Error
+          ~~~~~~~
+!!! error TS2741: Property 'someNewProperty' is missing in type 'Source4' but required in type 'Target4'.
+!!! related TS2728 issue52912.ts:11:18: 'someNewProperty' is declared here.
+

tests/baselines/reference/issue52912.js

@@ -0,0 +1,33 @@
+//// [tests/cases/compiler/issue52912.ts] ////
+
+//// [issue52912.ts]
+// Repro from #52912
+
+type Source1 = { array: Source2[] };
+type Source2 = { array: Source3[] };
+type Source3 = { array: Source4[] };
+type Source4 = {};
+
+type Target1 = { array: Target2[] };
+type Target2 = { array: Target3[] };
+type Target3 = { array: Target4[] };
+type Target4 = { someNewProperty: string };
+
+declare const source1: Source1;
+declare const source2: Source2;
+declare const source3: Source3;
+declare const source4: Source4;
+
+const target1: Target1 = source1; // Error
+const target2: Target2 = source2; // Error
+const target3: Target3 = source3; // Error
+const target4: Target4 = source4; // Error
+
+
+//// [issue52912.js]
+"use strict";
+// Repro from #52912
+const target1 = source1; // Error
+const target2 = source2; // Error
+const target3 = source3; // Error
+const target4 = source4; // Error

tests/baselines/reference/issue52912.symbols

@@ -0,0 +1,78 @@
+//// [tests/cases/compiler/issue52912.ts] ////
+
+=== issue52912.ts ===
+// Repro from #52912
+
+type Source1 = { array: Source2[] };
+>Source1 : Symbol(Source1, Decl(issue52912.ts, 0, 0))
+>array : Symbol(array, Decl(issue52912.ts, 2, 16))
+>Source2 : Symbol(Source2, Decl(issue52912.ts, 2, 36))
+
+type Source2 = { array: Source3[] };
+>Source2 : Symbol(Source2, Decl(issue52912.ts, 2, 36))
+>array : Symbol(array, Decl(issue52912.ts, 3, 16))
+>Source3 : Symbol(Source3, Decl(issue52912.ts, 3, 36))
+
+type Source3 = { array: Source4[] };
+>Source3 : Symbol(Source3, Decl(issue52912.ts, 3, 36))
+>array : Symbol(array, Decl(issue52912.ts, 4, 16))
+>Source4 : Symbol(Source4, Decl(issue52912.ts, 4, 36))
+
+type Source4 = {};
+>Source4 : Symbol(Source4, Decl(issue52912.ts, 4, 36))
+
+type Target1 = { array: Target2[] };
+>Target1 : Symbol(Target1, Decl(issue52912.ts, 5, 18))
+>array : Symbol(array, Decl(issue52912.ts, 7, 16))
+>Target2 : Symbol(Target2, Decl(issue52912.ts, 7, 36))
+
+type Target2 = { array: Target3[] };
+>Target2 : Symbol(Target2, Decl(issue52912.ts, 7, 36))
+>array : Symbol(array, Decl(issue52912.ts, 8, 16))
+>Target3 : Symbol(Target3, Decl(issue52912.ts, 8, 36))
+
+type Target3 = { array: Target4[] };
+>Target3 : Symbol(Target3, Decl(issue52912.ts, 8, 36))
+>array : Symbol(array, Decl(issue52912.ts, 9, 16))
+>Target4 : Symbol(Target4, Decl(issue52912.ts, 9, 36))
+
+type Target4 = { someNewProperty: string };
+>Target4 : Symbol(Target4, Decl(issue52912.ts, 9, 36))
+>someNewProperty : Symbol(someNewProperty, Decl(issue52912.ts, 10, 16))
+
+declare const source1: Source1;
+>source1 : Symbol(source1, Decl(issue52912.ts, 12, 13))
+>Source1 : Symbol(Source1, Decl(issue52912.ts, 0, 0))
+
+declare const source2: Source2;
+>source2 : Symbol(source2, Decl(issue52912.ts, 13, 13))
+>Source2 : Symbol(Source2, Decl(issue52912.ts, 2, 36))
+
+declare const source3: Source3;
+>source3 : Symbol(source3, Decl(issue52912.ts, 14, 13))
+>Source3 : Symbol(Source3, Decl(issue52912.ts, 3, 36))
+
+declare const source4: Source4;
+>source4 : Symbol(source4, Decl(issue52912.ts, 15, 13))
+>Source4 : Symbol(Source4, Decl(issue52912.ts, 4, 36))
+
+const target1: Target1 = source1; // Error
+>target1 : Symbol(target1, Decl(issue52912.ts, 17, 5))
+>Target1 : Symbol(Target1, Decl(issue52912.ts, 5, 18))
+>source1 : Symbol(source1, Decl(issue52912.ts, 12, 13))
+
+const target2: Target2 = source2; // Error
+>target2 : Symbol(target2, Decl(issue52912.ts, 18, 5))
+>Target2 : Symbol(Target2, Decl(issue52912.ts, 7, 36))
+>source2 : Symbol(source2, Decl(issue52912.ts, 13, 13))
+
+const target3: Target3 = source3; // Error
+>target3 : Symbol(target3, Decl(issue52912.ts, 19, 5))
+>Target3 : Symbol(Target3, Decl(issue52912.ts, 8, 36))
+>source3 : Symbol(source3, Decl(issue52912.ts, 14, 13))
+
+const target4: Target4 = source4; // Error
+>target4 : Symbol(target4, Decl(issue52912.ts, 20, 5))
+>Target4 : Symbol(Target4, Decl(issue52912.ts, 9, 36))
+>source4 : Symbol(source4, Decl(issue52912.ts, 15, 13))
+

tests/baselines/reference/issue52912.types

@@ -0,0 +1,91 @@
+//// [tests/cases/compiler/issue52912.ts] ////
+
+=== issue52912.ts ===
+// Repro from #52912
+
+type Source1 = { array: Source2[] };
+>Source1 : Source1
+>        : ^^^^^^^
+>array : Source2[]
+>      : ^^^^^^^^^
+
+type Source2 = { array: Source3[] };
+>Source2 : Source2
+>        : ^^^^^^^
+>array : Source3[]
+>      : ^^^^^^^^^
+
+type Source3 = { array: Source4[] };
+>Source3 : Source3
+>        : ^^^^^^^
+>array : Source4[]
+>      : ^^^^^^^^^
+
+type Source4 = {};
+>Source4 : Source4
+>        : ^^^^^^^
+
+type Target1 = { array: Target2[] };
+>Target1 : Target1
+>        : ^^^^^^^
+>array : Target2[]
+>      : ^^^^^^^^^
+
+type Target2 = { array: Target3[] };
+>Target2 : Target2
+>        : ^^^^^^^
+>array : Target3[]
+>      : ^^^^^^^^^
+
+type Target3 = { array: Target4[] };
+>Target3 : Target3
+>        : ^^^^^^^
+>array : Target4[]
+>      : ^^^^^^^^^
+
+type Target4 = { someNewProperty: string };
+>Target4 : Target4
+>        : ^^^^^^^
+>someNewProperty : string
+>                : ^^^^^^
+
+declare const source1: Source1;
+>source1 : Source1
+>        : ^^^^^^^
+
+declare const source2: Source2;
+>source2 : Source2
+>        : ^^^^^^^
+
+declare const source3: Source3;
+>source3 : Source3
+>        : ^^^^^^^
+
+declare const source4: Source4;
+>source4 : Source4
+>        : ^^^^^^^
+
+const target1: Target1 = source1; // Error
+>target1 : Target1
+>        : ^^^^^^^
+>source1 : Source1
+>        : ^^^^^^^
+
+const target2: Target2 = source2; // Error
+>target2 : Target2
+>        : ^^^^^^^
+>source2 : Source2
+>        : ^^^^^^^
+
+const target3: Target3 = source3; // Error
+>target3 : Target3
+>        : ^^^^^^^
+>source3 : Source3
+>        : ^^^^^^^
+
+const target4: Target4 = source4; // Error
+>target4 : Target4
+>        : ^^^^^^^
+>source4 : Source4
+>        : ^^^^^^^
+

tests/cases/compiler/issue52912.ts

@@ -0,0 +1,23 @@
+// @strict: true
+
+// Repro from #52912
+
+type Source1 = { array: Source2[] };
+type Source2 = { array: Source3[] };
+type Source3 = { array: Source4[] };
+type Source4 = {};
+
+type Target1 = { array: Target2[] };
+type Target2 = { array: Target3[] };
+type Target3 = { array: Target4[] };
+type Target4 = { someNewProperty: string };
+
+declare const source1: Source1;
+declare const source2: Source2;
+declare const source3: Source3;
+declare const source4: Source4;
+
+const target1: Target1 = source1; // Error
+const target2: Target2 = source2; // Error
+const target3: Target3 = source3; // Error
+const target4: Target4 = source4; // Error