Remove now-unneeded nongeneric checks

src/compiler/checker.ts

@@ -13121,24 +13121,14 @@ namespace ts {
                 }
                 return Ternary.False;
 
-                function isNonGeneric(type: Type) {
-                    // If we're already in identity relationship checking, we should use `isRelatedTo`
-                    // to catch the `Maybe` from an excessively deep type (which we then assume means
-                    // that the type could possibly contain a generic)
-                    if (relation === identityRelation) {
-                        return isRelatedTo(type, getPermissiveInstantiation(type)) === Ternary.True;
-                    }
-                    return isTypeIdenticalTo(type, getPermissiveInstantiation(type));
-                }
-
                 function relateVariances(sourceTypeArguments: ReadonlyArray<Type> | undefined, targetTypeArguments: ReadonlyArray<Type> | undefined, variances: Variance[]) {
                     if (some(variances, v => v === Variance.Unmeasurable)) {
                         return undefined;
                     }
                     if (result = typeArgumentsRelatedTo(sourceTypeArguments, targetTypeArguments, variances, reportErrors)) {
                         return result;
                     }
-                    const allowStructuralFallback = (targetTypeArguments && hasCovariantVoidArgument(targetTypeArguments, variances)) || isNonGeneric(source) || isNonGeneric(target);
+                    const allowStructuralFallback = targetTypeArguments && hasCovariantVoidArgument(targetTypeArguments, variances);
                     varianceCheckFailed = !allowStructuralFallback;
                     // The type arguments did not relate appropriately, but it may be because we have no variance
                     // information (in which case typeArgumentsRelatedTo defaulted to covariance for all type

tests/baselines/reference/checkInfiniteExpansionTermination.errors.txt

@@ -0,0 +1,32 @@
+tests/cases/compiler/checkInfiniteExpansionTermination.ts(16,1): error TS2322: Type 'ISubject<Bar>' is not assignable to type 'IObservable<Foo>'.
+  Types of property 'n' are incompatible.
+    Type 'IObservable<Bar[]>' is not assignable to type 'IObservable<Foo[]>'.
+      Type 'Bar[]' is not assignable to type 'Foo[]'.
+        Property 'x' is missing in type 'Bar' but required in type 'Foo'.
+
+
+==== tests/cases/compiler/checkInfiniteExpansionTermination.ts (1 errors) ====
+    // Regression test for #1002
+    // Before fix this code would cause infinite loop
+
+    interface IObservable<T> {
+        n: IObservable<T[]>; // Needed, must be T[]
+    }
+
+    // Needed
+    interface ISubject<T> extends IObservable<T> { }
+
+    interface Foo { x }
+    interface Bar { y }
+
+    var values: IObservable<Foo>;
+    var values2: ISubject<Bar>;
+    values = values2;
+    ~~~~~~
+!!! error TS2322: Type 'ISubject<Bar>' is not assignable to type 'IObservable<Foo>'.
+!!! error TS2322:   Types of property 'n' are incompatible.
+!!! error TS2322:     Type 'IObservable<Bar[]>' is not assignable to type 'IObservable<Foo[]>'.
+!!! error TS2322:       Type 'Bar[]' is not assignable to type 'Foo[]'.
+!!! error TS2322:         Property 'x' is missing in type 'Bar' but required in type 'Foo'.
+!!! related TS2728 tests/cases/compiler/checkInfiniteExpansionTermination.ts:11:17: 'x' is declared here.
+

tests/baselines/reference/invariantGenericErrorElaboration.errors.txt

@@ -0,0 +1,52 @@
+tests/cases/compiler/invariantGenericErrorElaboration.ts(3,7): error TS2322: Type 'Num' is not assignable to type 'Runtype<any>'.
+  Types of property 'constraint' are incompatible.
+    Type 'Constraint<Num>' is not assignable to type 'Constraint<Runtype<any>>'.
+      Types of property 'constraint' are incompatible.
+        Type 'Constraint<Constraint<Num>>' is not assignable to type 'Constraint<Constraint<Runtype<any>>>'.
+          Types of property 'constraint' are incompatible.
+            Type 'Constraint<Constraint<Constraint<Num>>>' is not assignable to type 'Constraint<Constraint<Constraint<Runtype<any>>>>'.
+              Type 'Constraint<Constraint<Runtype<any>>>' is not assignable to type 'Constraint<Constraint<Num>>'.
+                Types of property 'underlying' are incompatible.
+                  Type 'Constraint<Runtype<any>>' is not assignable to type 'Constraint<Num>'.
+tests/cases/compiler/invariantGenericErrorElaboration.ts(4,19): error TS2322: Type 'Num' is not assignable to type 'Runtype<any>'.
+
+
+==== tests/cases/compiler/invariantGenericErrorElaboration.ts (2 errors) ====
+    // Repro from #19746
+
+    const wat: Runtype<any> = Num;
+          ~~~
+!!! error TS2322: Type 'Num' is not assignable to type 'Runtype<any>'.
+!!! error TS2322:   Types of property 'constraint' are incompatible.
+!!! error TS2322:     Type 'Constraint<Num>' is not assignable to type 'Constraint<Runtype<any>>'.
+!!! error TS2322:       Types of property 'constraint' are incompatible.
+!!! error TS2322:         Type 'Constraint<Constraint<Num>>' is not assignable to type 'Constraint<Constraint<Runtype<any>>>'.
+!!! error TS2322:           Types of property 'constraint' are incompatible.
+!!! error TS2322:             Type 'Constraint<Constraint<Constraint<Num>>>' is not assignable to type 'Constraint<Constraint<Constraint<Runtype<any>>>>'.
+!!! error TS2322:               Type 'Constraint<Constraint<Runtype<any>>>' is not assignable to type 'Constraint<Constraint<Num>>'.
+!!! error TS2322:                 Types of property 'underlying' are incompatible.
+!!! error TS2322:                   Type 'Constraint<Runtype<any>>' is not assignable to type 'Constraint<Num>'.
+!!! related TS2728 tests/cases/compiler/invariantGenericErrorElaboration.ts:12:3: 'tag' is declared here.
+    const Foo = Obj({ foo: Num })
+                      ~~~
+!!! error TS2322: Type 'Num' is not assignable to type 'Runtype<any>'.
+!!! related TS6501 tests/cases/compiler/invariantGenericErrorElaboration.ts:17:34: The expected type comes from this index signature.
+
+    interface Runtype<A> {
+      constraint: Constraint<this>
+      witness: A
+    }
+
+    interface Num extends Runtype<number> {
+      tag: 'number'
+    }
+    declare const Num: Num
+
+    interface Obj<O extends { [_ in string]: Runtype<any> }> extends Runtype<{[K in keyof O]: O[K]['witness'] }> {}
+    declare function Obj<O extends { [_: string]: Runtype<any> }>(fields: O): Obj<O>;
+
+    interface Constraint<A extends Runtype<any>> extends Runtype<A['witness']> {
+      underlying: A,
+      check: (x: A['witness']) => void,
+    }
+

tests/baselines/reference/invariantGenericErrorElaboration.types

@@ -6,8 +6,8 @@ const wat: Runtype<any> = Num;
 >Num : Num
 
 const Foo = Obj({ foo: Num })
->Foo : Obj<{ foo: Num; }>
->Obj({ foo: Num }) : Obj<{ foo: Num; }>
+>Foo : any
+>Obj({ foo: Num }) : any
 >Obj : <O extends { [_: string]: Runtype<any>; }>(fields: O) => Obj<O>
 >{ foo: Num } : { foo: Num; }
 >foo : Num

tests/baselines/reference/recursiveTypeComparison.errors.txt

@@ -0,0 +1,27 @@
+tests/cases/compiler/recursiveTypeComparison.ts(14,5): error TS2322: Type 'Observable<{}>' is not assignable to type 'Property<number>'.
+  Types of property 'needThisOne' are incompatible.
+    Type 'Observable<{}>' is not assignable to type 'Observable<number>'.
+      Type '{}' is not assignable to type 'number'.
+
+
+==== tests/cases/compiler/recursiveTypeComparison.ts (1 errors) ====
+    // Before fix this would take an exceeding long time to complete (#1170)
+
+    interface Observable<T> {
+        // This member can't be of type T, Property<T>, or Observable<anything but T>
+        needThisOne: Observable<T>;
+        // Add more to make it slower
+        expo1: Property<T[]>; //  0.31 seconds in check
+        expo2: Property<T[]>; //  3.11 seconds
+        expo3: Property<T[]>; // 82.28 seconds
+    }
+    interface Property<T> extends Observable<T> { }
+
+    var p: Observable<{}>;
+    var stuck: Property<number> = p;
+        ~~~~~
+!!! error TS2322: Type 'Observable<{}>' is not assignable to type 'Property<number>'.
+!!! error TS2322:   Types of property 'needThisOne' are incompatible.
+!!! error TS2322:     Type 'Observable<{}>' is not assignable to type 'Observable<number>'.
+!!! error TS2322:       Type '{}' is not assignable to type 'number'.
+

tests/baselines/reference/strictFunctionTypesErrors.errors.txt

@@ -62,9 +62,13 @@ tests/cases/compiler/strictFunctionTypesErrors.ts(84,1): error TS2322: Type 'Fun
 tests/cases/compiler/strictFunctionTypesErrors.ts(111,1): error TS2322: Type 'Comparer2<Dog>' is not assignable to type 'Comparer2<Animal>'.
   Property 'dog' is missing in type 'Animal' but required in type 'Dog'.
 tests/cases/compiler/strictFunctionTypesErrors.ts(126,1): error TS2322: Type 'Crate<Dog>' is not assignable to type 'Crate<Animal>'.
-  Type 'Animal' is not assignable to type 'Dog'.
+  Types of property 'onSetItem' are incompatible.
+    Type '(item: Dog) => void' is not assignable to type '(item: Animal) => void'.
+      Types of parameters 'item' and 'item' are incompatible.
+        Type 'Animal' is not assignable to type 'Dog'.
 tests/cases/compiler/strictFunctionTypesErrors.ts(127,1): error TS2322: Type 'Crate<Animal>' is not assignable to type 'Crate<Dog>'.
-  Type 'Animal' is not assignable to type 'Dog'.
+  Types of property 'item' are incompatible.
+    Type 'Animal' is not assignable to type 'Dog'.
 tests/cases/compiler/strictFunctionTypesErrors.ts(133,1): error TS2322: Type '(f: (x: Dog) => Dog) => void' is not assignable to type '(f: (x: Animal) => Animal) => void'.
   Types of parameters 'f' and 'f' are incompatible.
     Type 'Animal' is not assignable to type 'Dog'.
@@ -304,11 +308,15 @@ tests/cases/compiler/strictFunctionTypesErrors.ts(155,5): error TS2322: Type '(c
     animalCrate = dogCrate;  // Error
     ~~~~~~~~~~~
 !!! error TS2322: Type 'Crate<Dog>' is not assignable to type 'Crate<Animal>'.
-!!! error TS2322:   Type 'Animal' is not assignable to type 'Dog'.
+!!! error TS2322:   Types of property 'onSetItem' are incompatible.
+!!! error TS2322:     Type '(item: Dog) => void' is not assignable to type '(item: Animal) => void'.
+!!! error TS2322:       Types of parameters 'item' and 'item' are incompatible.
+!!! error TS2322:         Type 'Animal' is not assignable to type 'Dog'.
     dogCrate = animalCrate;  // Error
     ~~~~~~~~
 !!! error TS2322: Type 'Crate<Animal>' is not assignable to type 'Crate<Dog>'.
-!!! error TS2322:   Type 'Animal' is not assignable to type 'Dog'.
+!!! error TS2322:   Types of property 'item' are incompatible.
+!!! error TS2322:     Type 'Animal' is not assignable to type 'Dog'.
 
     // Verify that callback parameters are strictly checked