feat: check whether type parameter bounds are named types (#878)

Closes #876 ### Summary of Changes Add a check to ensure that the bound of a type parameter is a named type.
Safe-DS · Feb 10, 2024 · d8b4168 · d8b4168
1 parent aa444d4
commit d8b4168
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Showing 4 changed files with 151 additions and 23 deletions.
diff --git a/packages/safe-ds-lang/src/language/validation/other/declarations/typeParameters.ts b/packages/safe-ds-lang/src/language/validation/other/declarations/typeParameters.ts
@@ -12,12 +12,16 @@ import {
     SdsClass,
     SdsDeclaration,
     SdsTypeParameter,
+    SdsTypeParameterBound,
 } from '../../../generated/ast.js';
 import { isStatic, TypeParameter } from '../../../helpers/nodeProperties.js';
 import { SafeDsServices } from '../../../safe-ds-module.js';
 import { SafeDsNodeMapper } from '../../../helpers/safe-ds-node-mapper.js';
+import { NamedType, UnknownType } from '../../../typing/model.js';
+import { SafeDsTypeComputer } from '../../../typing/safe-ds-type-computer.js';
 
 export const CODE_TYPE_PARAMETER_INSUFFICIENT_CONTEXT = 'type-parameter/insufficient-context';
+export const CODE_TYPE_PARAMETER_INVALID_BOUND = 'type-parameter/invalid-bound';
 export const CODE_TYPE_PARAMETER_MULTIPLE_BOUNDS = 'type-parameter/multiple-bounds';
 export const CODE_TYPE_PARAMETER_USAGE = 'type-parameter/usage';
 export const CODE_TYPE_PARAMETER_VARIANCE = 'type-parameter/variance';
@@ -59,32 +63,54 @@ export const typeParameterMustHaveSufficientContext = (node: SdsTypeParameter, a
     }
 };
 
-export const typeParameterMustNotHaveMultipleBounds = (node: SdsTypeParameter, accept: ValidationAcceptor) => {
-    const bounds = TypeParameter.getBounds(node);
+export const typeParameterMustNotHaveMultipleBounds = (services: SafeDsServices) => {
+    const typeComputer = services.types.TypeComputer;
 
-    let foundLowerBound = false;
-    let foundUpperBound = false;
+    return (node: SdsTypeParameter, accept: ValidationAcceptor) => {
+        const bounds = TypeParameter.getBounds(node);
 
-    for (const bound of bounds) {
-        if (bound.operator === 'super') {
-            if (foundLowerBound) {
-                accept('error', 'A type parameter can only have a single lower bound.', {
-                    node: bound,
-                    code: CODE_TYPE_PARAMETER_MULTIPLE_BOUNDS,
-                });
-            }
+        let foundLowerBound = false;
+        let foundUpperBound = false;
 
-            foundLowerBound = true;
-        } else if (bound.operator === 'sub') {
-            if (foundUpperBound) {
-                accept('error', 'A type parameter can only have a single upper bound.', {
-                    node: bound,
-                    code: CODE_TYPE_PARAMETER_MULTIPLE_BOUNDS,
-                });
+        for (const bound of bounds) {
+            if (bound.operator === 'super') {
+                if (foundLowerBound) {
+                    accept('error', 'A type parameter can only have a single lower bound.', {
+                        node: bound,
+                        code: CODE_TYPE_PARAMETER_MULTIPLE_BOUNDS,
+                    });
+                } else {
+                    checkIfBoundIsValid(bound, typeComputer, accept);
+                    foundLowerBound = true;
+                }
+            } else if (bound.operator === 'sub') {
+                if (foundUpperBound) {
+                    accept('error', 'A type parameter can only have a single upper bound.', {
+                        node: bound,
+                        code: CODE_TYPE_PARAMETER_MULTIPLE_BOUNDS,
+                    });
+                } else {
+                    checkIfBoundIsValid(bound, typeComputer, accept);
+                    foundUpperBound = true;
+                }
             }
-
-            foundUpperBound = true;
         }
+    };
+};
+
+const checkIfBoundIsValid = (
+    node: SdsTypeParameterBound,
+    typeComputer: SafeDsTypeComputer,
+    accept: ValidationAcceptor,
+) => {
+    const boundType = typeComputer.computeType(node.rightOperand);
+
+    if (boundType !== UnknownType && !(boundType instanceof NamedType)) {
+        accept('error', 'Bounds of type parameters must be named types.', {
+            node,
+            property: 'rightOperand',
+            code: CODE_TYPE_PARAMETER_INVALID_BOUND,
+        });
     }
 };
 

diff --git a/packages/safe-ds-lang/src/language/validation/safe-ds-validator.ts b/packages/safe-ds-lang/src/language/validation/safe-ds-validator.ts
@@ -352,7 +352,7 @@ export const registerValidationChecks = function (services: SafeDsServices) {
         SdsTypeParameter: [
             typeParameterMustHaveSufficientContext,
             typeParameterMustBeUsedInCorrectPosition(services),
-            typeParameterMustNotHaveMultipleBounds,
+            typeParameterMustNotHaveMultipleBounds(services),
             typeParameterMustOnlyBeVariantOnClass,
         ],
         SdsTypeParameterBound: [typeParameterBoundLeftOperandMustBeOwnTypeParameter],

diff --git a/...ns/constraints/type parameter bounds/left operand must be own type parameter/main.sdstest b/...ns/constraints/type parameter bounds/left operand must be own type parameter/main.sdstest
@@ -1,4 +1,4 @@
-package tests.validation.other.declarations.constraints.typeParameterBounds.typeParameterOnContainer
+package tests.validation.other.declarations.constraints.typeParameterBounds.leftOperandMustBeOwnTypeParameter
 
 annotation MyAnnotation where {
     // $TEST$ no error "The left operand must refer to a type parameter of the declaration with the bound."

diff --git a/...urces/validation/other/declarations/type parameters/bound must be named type/main.sdstest b/...urces/validation/other/declarations/type parameters/bound must be named type/main.sdstest
@@ -0,0 +1,102 @@
+package tests.validation.other.declarations.typeParameters.boundMustBeNamedType
+
+class C
+enum E {
+    V
+}
+
+class MyClass1<T> where {
+    // $TEST$ error "Bounds of type parameters must be named types."
+    T sub »() -> ()«,
+    // $TEST$ no error "Bounds of type parameters must be named types."
+    T sub »() -> ()«,
+
+    // $TEST$ error "Bounds of type parameters must be named types."
+    T super »() -> ()«,
+    // $TEST$ no error "Bounds of type parameters must be named types."
+    T super »() -> ()«,
+}
+
+class MyClass2<T> where {
+    // $TEST$ error "Bounds of type parameters must be named types."
+    T sub »literal<1>«,
+    // $TEST$ no error "Bounds of type parameters must be named types."
+    T sub »literal<1>«,
+
+    // $TEST$ error "Bounds of type parameters must be named types."
+    T super »literal<1>«,
+    // $TEST$ no error "Bounds of type parameters must be named types."
+    T super »literal<1>«,
+}
+
+class MyClass3<T> where {
+    // $TEST$ no error "Bounds of type parameters must be named types."
+    T sub »C«,
+    // $TEST$ no error "Bounds of type parameters must be named types."
+    T sub »C«,
+
+    // $TEST$ no error "Bounds of type parameters must be named types."
+    T super »C«,
+    // $TEST$ no error "Bounds of type parameters must be named types."
+    T super »C«,
+}
+
+class MyClass4<T> where {
+    // $TEST$ no error "Bounds of type parameters must be named types."
+    T sub »E«,
+    // $TEST$ no error "Bounds of type parameters must be named types."
+    T sub »E«,
+
+    // $TEST$ no error "Bounds of type parameters must be named types."
+    T super »E«,
+    // $TEST$ no error "Bounds of type parameters must be named types."
+    T super »E«,
+}
+
+class MyClass5<T> where {
+    // $TEST$ no error "Bounds of type parameters must be named types."
+    T sub »E.V«,
+    // $TEST$ no error "Bounds of type parameters must be named types."
+    T sub »E.V«,
+
+     // $TEST$ no error "Bounds of type parameters must be named types."
+    T super »E.V«,
+    // $TEST$ no error "Bounds of type parameters must be named types."
+    T super »E.V«,
+}
+
+class MyClass6<T1, T2> where {
+    // $TEST$ no error "Bounds of type parameters must be named types."
+    T1 sub »T2«,
+    // $TEST$ no error "Bounds of type parameters must be named types."
+    T1 sub »T2«,
+
+    // $TEST$ no error "Bounds of type parameters must be named types."
+    T1 super »T2«,
+    // $TEST$ no error "Bounds of type parameters must be named types."
+    T1 super »T2«,
+}
+
+class MyClass7<T> where {
+    // $TEST$ error "Bounds of type parameters must be named types."
+    T sub »union<C, E>«,
+    // $TEST$ no error "Bounds of type parameters must be named types."
+    T sub »union<C, E>«,
+
+    // $TEST$ error "Bounds of type parameters must be named types."
+    T super »union<C, E>«,
+    // $TEST$ no error "Bounds of type parameters must be named types."
+    T super »union<C, E>«,
+}
+
+class MyClass8<T> where {
+    // $TEST$ no error "Bounds of type parameters must be named types."
+    T sub »Unresolved«,
+    // $TEST$ no error "Bounds of type parameters must be named types."
+    T sub »Unresolved«,
+
+    // $TEST$ no error "Bounds of type parameters must be named types."
+    T super »Unresolved«,
+    // $TEST$ no error "Bounds of type parameters must be named types."
+    T super »Unresolved«,
+}