[cfe] Remove IsSubtypeOf.onlyIfIgnoringNullabilities

Change-Id: I584e079c273e48a007590fd63575321fe49f4b6a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/434060
Reviewed-by: Johnni Winther <[email protected]>
Commit-Queue: Chloe Stefantsova <[email protected]>

Author: chloestefantsova

pkg/kernel/lib/src/types.dart

@@ -92,10 +92,7 @@ class Types with StandardBounds {
           when tClassReference == hierarchy.coreTypes.objectClass.reference &&
               s.extensionTypeErasure.isPotentiallyNullable &&
               !t.isPotentiallyNullable:
-        return new IsSubtypeOf.onlyIfIgnoringNullabilities(
-          subtype: s,
-          supertype: t,
-        );
+        return const IsSubtypeOf.failure();
       case (_, InterfaceType(classReference: Reference tClassReference))
           when tClassReference == hierarchy.coreTypes.objectClass.reference &&
               s is! FutureOrType:
@@ -364,12 +361,7 @@ class Types with StandardBounds {
                 /// From the NNBD spec: For each j such that r0j is required,
                 /// then there exists an i in n+1...q such that xj = yi, and r1i
                 /// is required
-                result = result.and(
-                  new IsSubtypeOf.onlyIfIgnoringNullabilities(
-                    subtype: sFunctionType,
-                    supertype: tFunctionType,
-                  ),
-                );
+                result = const IsSubtypeOf.failure();
               }
             }
             if (sCount == sNamedParameters.length) {
@@ -393,12 +385,7 @@ class Types with StandardBounds {
             /// there exists an i in n+1...q such that xj = yi, and r1i is
             /// required
             if (sNamedParameter.isRequired && !tNamedParameter.isRequired) {
-              result = result.and(
-                new IsSubtypeOf.onlyIfIgnoringNullabilities(
-                  subtype: sFunctionType,
-                  supertype: tFunctionType,
-                ),
-              );
+              result = const IsSubtypeOf.failure();
             }
           }
           for (; sCount < sNamedParameters.length; sCount++) {
@@ -407,12 +394,7 @@ class Types with StandardBounds {
               /// From the NNBD spec: For each j such that r0j is required, then
               /// there exists an i in n+1...q such that xj = yi, and r1i is
               /// required
-              result = result.and(
-                new IsSubtypeOf.onlyIfIgnoringNullabilities(
-                  subtype: sFunctionType,
-                  supertype: tFunctionType,
-                ),
-              );
+              result = const IsSubtypeOf.failure();
             }
           }
         }

pkg/kernel/lib/type_environment.dart

@@ -557,12 +557,6 @@ class IsSubtypeOf {
   /// Subtype check succeeds.
   const IsSubtypeOf.success() : this._internal(true, null, null);
 
-  /// Legacy constructor for pre-Null Safe mode.
-  // TODO(cstefantsova): Remove this.
-  const IsSubtypeOf.onlyIfIgnoringNullabilities(
-      {DartType? subtype, DartType? supertype})
-      : this._internal(false, subtype, supertype);
-
   /// Subtype check fails.
   const IsSubtypeOf.failure() : this._internal(false, null, null);
 
@@ -582,12 +576,10 @@ class IsSubtypeOf {
       if (supertype is InvalidType) {
         return const IsSubtypeOf.success();
       }
-      return new IsSubtypeOf.onlyIfIgnoringNullabilities(
-          subtype: subtype, supertype: supertype);
+      return const IsSubtypeOf.failure();
     }
     if (supertype is InvalidType) {
-      return new IsSubtypeOf.onlyIfIgnoringNullabilities(
-          subtype: subtype, supertype: supertype);
+      return const IsSubtypeOf.failure();
     }
 
     return _basedSolelyOnNullabilitiesNotInvalidType(subtype, supertype);
@@ -624,8 +616,7 @@ class IsSubtypeOf {
           return const IsSubtypeOf.success();
         }
       }
-      return new IsSubtypeOf.onlyIfIgnoringNullabilities(
-          subtype: subtype, supertype: supertype);
+      return const IsSubtypeOf.failure();
     }
     return const IsSubtypeOf.success();
   }