feat: isSubtypeOf always returns true if 1. op is Nothing or 2.…

… op is `Any?`
Safe-DS · Feb 20, 2024 · bf18e02 · bf18e02
1 parent 9d6ce28
commit bf18e02
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Showing 2 changed files with 36 additions and 4 deletions.
diff --git a/packages/safe-ds-lang/src/language/typing/safe-ds-type-checker.ts b/packages/safe-ds-lang/src/language/typing/safe-ds-type-checker.ts
@@ -61,9 +61,13 @@ export class SafeDsTypeChecker {
      * Checks whether {@link type} is a subtype of {@link other}.
      */
     isSubtypeOf = (type: Type, other: Type, options: TypeCheckOptions = {}): boolean => {
-        if (type === UnknownType || other === UnknownType) {
+        if (type.equals(this.coreTypes.Nothing) || other.equals(this.coreTypes.AnyOrNull)) {
+            return true;
+        } else if (type === UnknownType || other === UnknownType) {
             return false;
-        } else if (other instanceof TypeParameterType) {
+        }
+
+        if (other instanceof TypeParameterType) {
             const otherUpperBound = this.typeComputer().computeUpperBound(other);
             return this.isSubtypeOf(type, otherUpperBound, options);
         } else if (other instanceof UnionType) {
@@ -281,6 +285,8 @@ export class SafeDsTypeChecker {
     private staticTypeIsSubtypeOf(type: StaticType, other: Type, options: TypeCheckOptions): boolean {
         if (other instanceof CallableType) {
             return this.isSubtypeOf(this.associatedCallableTypeForStaticType(type), other, options);
+        } else if (other instanceof ClassType) {
+            return other.declaration === this.builtinClasses.Any;
         } else {
             return type.equals(other);
         }

diff --git a/packages/safe-ds-lang/tests/language/typing/type checker/isSubOrSupertypeOf.test.ts b/packages/safe-ds-lang/tests/language/typing/type checker/isSubOrSupertypeOf.test.ts
@@ -604,6 +604,22 @@ const basic = async (): Promise<IsSubOrSupertypeOfTest[]> => {
             type2: callableType12,
             expected: true,
         },
+        // Static type to class type
+        {
+            type1: factory.createStaticType(classType1),
+            type2: classType1,
+            expected: false,
+        },
+        {
+            type1: factory.createStaticType(classType1),
+            type2: coreTypes.Any,
+            expected: true,
+        },
+        {
+            type1: factory.createStaticType(classType1),
+            type2: coreTypes.AnyOrNull,
+            expected: true,
+        },
         // Static type to static type
         {
             type1: factory.createStaticType(classType1),
@@ -658,6 +674,16 @@ const basic = async (): Promise<IsSubOrSupertypeOfTest[]> => {
             type2: UnknownType,
             expected: false,
         },
+        {
+            type1: coreTypes.Nothing,
+            type2: UnknownType,
+            expected: true,
+        },
+        {
+            type1: UnknownType,
+            type2: coreTypes.AnyOrNull,
+            expected: true,
+        },
     ];
 };
 
@@ -1011,7 +1037,7 @@ const typeParameterTypes = async (): Promise<IsSubOrSupertypeOfTest[]> => {
         {
             type1: unresolved,
             type2: unbounded,
-            expected: false,
+            expected: true,
         },
         {
             type1: coreTypes.AnyOrNull,
@@ -1107,7 +1133,7 @@ const typeParameterTypes = async (): Promise<IsSubOrSupertypeOfTest[]> => {
         {
             type1: coreTypes.Nothing,
             type2: unresolved,
-            expected: false,
+            expected: true,
         },
 
         // Compare to some other type