feat: port remaining validation infos that don't need partial evaluat…

…ion (#607)

Closes partially #543.

### Summary of Changes

Show an info if
* an argument list can be removed,
* a type argument list can be removed,
* a safe access can be removed.

---------

Co-authored-by: megalinter-bot <129584137+megalinter-bot@users.noreply.github.com>

src/language/helpers/nodeProperties.ts

@@ -63,6 +63,10 @@ export const isNamedTypeArgument = (node: SdsTypeArgument): boolean => {
     return Boolean(node.typeParameter);
 };
 
+export const isRequiredParameter = (node: SdsParameter): boolean => {
+    return !node.defaultValue && !node.isVariadic;
+};
+
 export const isStatic = (node: SdsClassMember): boolean => {
     if (isSdsClass(node) || isSdsEnum(node)) {
         return true;

src/language/validation/safe-ds-validator.ts

@@ -16,13 +16,17 @@ import {
     segmentMustContainUniqueNames,
 } from './names.js';
 import {
+    annotationCallArgumentListShouldBeNeeded,
     annotationParameterListShouldNotBeEmpty,
     assignmentShouldHaveMoreThanWildcardsAsAssignees,
+    callArgumentListShouldBeNeeded,
     classBodyShouldNotBeEmpty,
     constraintListShouldNotBeEmpty,
     enumBodyShouldNotBeEmpty,
     enumVariantParameterListShouldNotBeEmpty,
     functionResultListShouldNotBeEmpty,
+    memberAccessNullSafetyShouldBeNeeded,
+    namedTypeTypeArgumentListShouldBeNeeded,
     segmentResultListShouldNotBeEmpty,
     typeParameterListShouldNotBeEmpty,
     unionTypeShouldNotHaveASingularTypeArgument,
@@ -52,9 +56,11 @@ export const registerValidationChecks = function (services: SafeDsServices) {
     const checks: ValidationChecks<SafeDsAstType> = {
         SdsAssignment: [assignmentShouldHaveMoreThanWildcardsAsAssignees],
         SdsAnnotation: [annotationMustContainUniqueNames, annotationParameterListShouldNotBeEmpty],
+        SdsAnnotationCall: [annotationCallArgumentListShouldBeNeeded],
         SdsArgumentList: [argumentListMustNotHavePositionalArgumentsAfterNamedArguments],
         SdsAttribute: [attributeMustHaveTypeHint],
         SdsBlockLambda: [blockLambdaMustContainUniqueNames],
+        SdsCall: [callArgumentListShouldBeNeeded(services)],
         SdsCallableType: [callableTypeMustContainUniqueNames, callableTypeMustNotHaveOptionalParameters],
         SdsClass: [classMustContainUniqueNames],
         SdsClassBody: [classBodyShouldNotBeEmpty],
@@ -65,7 +71,9 @@ export const registerValidationChecks = function (services: SafeDsServices) {
         SdsEnumVariant: [enumVariantMustContainUniqueNames, enumVariantParameterListShouldNotBeEmpty],
         SdsExpressionLambda: [expressionLambdaMustContainUniqueNames],
         SdsFunction: [functionMustContainUniqueNames, functionResultListShouldNotBeEmpty],
+        SdsMemberAccess: [memberAccessNullSafetyShouldBeNeeded(services)],
         SdsModule: [moduleDeclarationsMustMatchFileKind, moduleWithDeclarationsMustStatePackage],
+        SdsNamedType: [namedTypeTypeArgumentListShouldBeNeeded],
         SdsParameter: [parameterMustHaveTypeHint, parameterMustNotBeVariadicAndOptional],
         SdsParameterList: [
             parameterListMustNotHaveOptionalAndVariadicParameters,

src/language/validation/style.ts

@@ -1,33 +1,88 @@
 import {
+    isSdsEnumVariant,
     isSdsWildcard,
     SdsAnnotation,
+    SdsAnnotationCall,
     SdsAssignment,
+    SdsCall,
     SdsClassBody,
     SdsConstraintList,
     SdsEnumBody,
     SdsEnumVariant,
     SdsFunction,
+    SdsMemberAccess,
+    SdsNamedType,
     SdsSegment,
     SdsTypeParameterList,
     SdsUnionType,
 } from '../generated/ast.js';
 import { ValidationAcceptor } from 'langium';
 import { isEmpty } from 'radash';
+import { isRequiredParameter, parametersOrEmpty, typeParametersOrEmpty } from '../helpers/nodeProperties.js';
+import { SafeDsServices } from '../safe-ds-module.js';
+import { UnknownType } from '../typing/model.js';
 
 export const CODE_STYLE_UNNECESSARY_ASSIGNMENT = 'style/unnecessary-assignment';
 export const CODE_STYLE_UNNECESSARY_ARGUMENT_LIST = 'style/unnecessary-argument-list';
 export const CODE_STYLE_UNNECESSARY_BODY = 'style/unnecessary-body';
 export const CODE_STYLE_UNNECESSARY_CONSTRAINT_LIST = 'style/unnecessary-constraint-list';
 export const CODE_STYLE_UNNECESSARY_ELVIS_OPERATOR = 'style/unnecessary-elvis-operator';
-export const CODE_STYLE_UNNECESSARY_SAFE_ACCESS = 'style/unnecessary-safe-access';
 export const CODE_STYLE_UNNECESSARY_PARAMETER_LIST = 'style/unnecessary-parameter-list';
 export const CODE_STYLE_UNNECESSARY_RESULT_LIST = 'style/unnecessary-result-list';
+export const CODE_STYLE_UNNECESSARY_SAFE_ACCESS = 'style/unnecessary-safe-access';
 export const CODE_STYLE_UNNECESSARY_TYPE_ARGUMENT_LIST = 'style/unnecessary-type-argument-list';
 export const CODE_STYLE_UNNECESSARY_TYPE_PARAMETER_LIST = 'style/unnecessary-type-parameter-list';
 export const CODE_STYLE_UNNECESSARY_UNION_TYPE = 'style/unnecessary-union-type';
 
 // -----------------------------------------------------------------------------
-// Unnecessary assignment
+// Unnecessary argument lists
+// -----------------------------------------------------------------------------
+
+export const annotationCallArgumentListShouldBeNeeded = (node: SdsAnnotationCall, accept: ValidationAcceptor): void => {
+    const argumentList = node.argumentList;
+    if (!argumentList || !isEmpty(argumentList.arguments)) {
+        // If there are arguments, they are either needed or erroneous (i.e. we already show an error)
+        return;
+    }
+
+    const annotation = node.annotation?.ref;
+    if (!annotation) {
+        return;
+    }
+
+    const hasRequiredParameters = parametersOrEmpty(annotation).some(isRequiredParameter);
+    if (!hasRequiredParameters) {
+        accept('info', 'This argument list can be removed.', {
+            node: argumentList,
+            code: CODE_STYLE_UNNECESSARY_ARGUMENT_LIST,
+        });
+    }
+};
+
+export const callArgumentListShouldBeNeeded =
+    (services: SafeDsServices) =>
+    (node: SdsCall, accept: ValidationAcceptor): void => {
+        const argumentList = node.argumentList;
+        if (!argumentList || !isEmpty(argumentList.arguments)) {
+            // If there are arguments, they are either needed or erroneous (i.e. we already show an error)
+            return;
+        }
+
+        const callable = services.helpers.NodeMapper.callToCallableOrUndefined(node);
+        if (!isSdsEnumVariant(callable)) {
+            return;
+        }
+
+        if (isEmpty(parametersOrEmpty(callable))) {
+            accept('info', 'This argument list can be removed.', {
+                node: argumentList,
+                code: CODE_STYLE_UNNECESSARY_ARGUMENT_LIST,
+            });
+        }
+    };
+
+// -----------------------------------------------------------------------------
+// Unnecessary assignments
 // -----------------------------------------------------------------------------
 
 export const assignmentShouldHaveMoreThanWildcardsAsAssignees = (
@@ -66,7 +121,7 @@ export const enumBodyShouldNotBeEmpty = (node: SdsEnumBody, accept: ValidationAc
 };
 
 // -----------------------------------------------------------------------------
-// Unnecessary constraint list
+// Unnecessary constraint lists
 // -----------------------------------------------------------------------------
 
 export const constraintListShouldNotBeEmpty = (node: SdsConstraintList, accept: ValidationAcceptor) => {
@@ -126,6 +181,54 @@ export const segmentResultListShouldNotBeEmpty = (node: SdsSegment, accept: Vali
     }
 };
 
+// -----------------------------------------------------------------------------
+// Unnecessary safe access
+// -----------------------------------------------------------------------------
+
+export const memberAccessNullSafetyShouldBeNeeded =
+    (services: SafeDsServices) =>
+    (node: SdsMemberAccess, accept: ValidationAcceptor): void => {
+        if (!node.isNullSafe) {
+            return;
+        }
+
+        const receiverType = services.types.TypeComputer.computeType(node.receiver);
+        if (receiverType === UnknownType) {
+            return;
+        }
+
+        if (!receiverType.isNullable) {
+            accept('info', 'The receiver is never null, so the safe access is unnecessary.', {
+                node,
+                code: CODE_STYLE_UNNECESSARY_SAFE_ACCESS,
+            });
+        }
+    };
+
+// -----------------------------------------------------------------------------
+// Unnecessary type argument lists
+// -----------------------------------------------------------------------------
+
+export const namedTypeTypeArgumentListShouldBeNeeded = (node: SdsNamedType, accept: ValidationAcceptor): void => {
+    const typeArgumentList = node.typeArgumentList;
+    if (!typeArgumentList || !isEmpty(typeArgumentList.typeArguments)) {
+        // If there are type arguments, they are either needed or erroneous (i.e. we already show an error)
+        return;
+    }
+
+    const namedTypeDeclaration = node.declaration?.ref;
+    if (!namedTypeDeclaration) {
+        return;
+    }
+
+    if (isEmpty(typeParametersOrEmpty(namedTypeDeclaration))) {
+        accept('info', 'This type argument list can be removed.', {
+            node: typeArgumentList,
+            code: CODE_STYLE_UNNECESSARY_ARGUMENT_LIST,
+        });
+    }
+};
+
 // -----------------------------------------------------------------------------
 // Unnecessary type parameter lists
 // -----------------------------------------------------------------------------

tests/resources/validation/style/unnecessary argument list in annotation call/main.sdstest

@@ -0,0 +1,35 @@
+package tests.validation.style.unnecessaryArgumentListInAnnotationCall
+
+@Repeatable
+annotation AnnotationWithoutParameterList
+
+@Repeatable
+annotation AnnotationWithEmptyParameterList()
+
+@Repeatable
+annotation AnnotationWithoutRequiredParameters(a: Int = 0, vararg b: Int)
+
+@Repeatable
+annotation AnnotationWithRequiredParameters(a: Int)
+
+// $TEST$ info "This argument list can be removed."
+@AnnotationWithoutParameterList»()«
+// $TEST$ no info "This argument list can be removed."
+@AnnotationWithoutParameterList»(1)«
+// $TEST$ info "This argument list can be removed."
+@AnnotationWithEmptyParameterList»()«
+// $TEST$ no info "This argument list can be removed."
+@AnnotationWithEmptyParameterList»(1)«
+// $TEST$ info "This argument list can be removed."
+@AnnotationWithoutRequiredParameters»()«
+// $TEST$ no info "This argument list can be removed."
+@AnnotationWithoutRequiredParameters»(1)«
+// $TEST$ no info "This argument list can be removed."
+@AnnotationWithRequiredParameters»()«
+// $TEST$ no info "This argument list can be removed."
+@AnnotationWithRequiredParameters»(1)«
+// $TEST$ no info "This argument list can be removed."
+@Unresolved»()«
+// $TEST$ no info "This argument list can be removed."
+@Unresolved»(1)«
+class MyClass

tests/resources/validation/style/unnecessary argument list in call/main.sdstest

@@ -0,0 +1,65 @@
+package tests.validation.style.unnecessaryArgumentListInCall
+
+annotation MyAnnotation
+
+class MyClass()
+
+enum MyEnum {
+    EnumVariantWithoutParameterList
+    EnumVariantWithEmptyParameterList()
+    EnumVariantWithoutRequiredParameters(a: Int = 0, vararg b: Int)
+    EnumVariantWithRequiredParameters(a: Int)
+}
+
+fun myFunction()
+
+segment mySegment1() {}
+
+segment mySegment2(
+    callableType: () -> (),
+) {
+    val blockLambda = () {};
+    val expressionLambda = () -> 0;
+
+    // $TEST$ no info "This argument list can be removed."
+    MyAnnotation»()«;
+
+    // $TEST$ no info "This argument list can be removed."
+    MyClass»()«;
+
+    // $TEST$ info "This argument list can be removed."
+    MyEnum.EnumVariantWithoutParameterList»()«;
+    // $TEST$ no info "This argument list can be removed."
+    MyEnum.EnumVariantWithoutParameterList»(1)«;
+    // $TEST$ info "This argument list can be removed."
+    MyEnum.EnumVariantWithEmptyParameterList»()«;
+    // $TEST$ no info "This argument list can be removed."
+    MyEnum.EnumVariantWithEmptyParameterList»(1)«;
+    // $TEST$ no info "This argument list can be removed."
+    MyEnum.EnumVariantWithoutRequiredParameters»()«;
+    // $TEST$ no info "This argument list can be removed."
+    MyEnum.EnumVariantWithoutRequiredParameters»(1)«;
+    // $TEST$ no info "This argument list can be removed."
+    MyEnum.EnumVariantWithRequiredParameters»()«;
+    // $TEST$ no info "This argument list can be removed."
+    MyEnum.EnumVariantWithRequiredParameters»(1)«;
+    // $TEST$ no info "This argument list can be removed."
+    MyEnum.Unresolved»()«;
+    // $TEST$ no info "This argument list can be removed."
+    MyEnum.Unresolved»(1)«;
+
+    // $TEST$ no info "This argument list can be removed."
+    myFunction»()«;
+
+    // $TEST$ no info "This argument list can be removed."
+    mySegment1»()«;
+
+    // $TEST$ no info "This argument list can be removed."
+    callableType»()«;
+
+    // $TEST$ no info "This argument list can be removed."
+    blockLambda»()«;
+
+    // $TEST$ no info "This argument list can be removed."
+    expressionLambda»()«;
+}

tests/resources/validation/style/unnecessary safe access/main.sdstest

@@ -0,0 +1,10 @@
+package tests.validation.style.unnecessarySafeAccess
+
+pipeline test {
+    // $TEST$ info "The receiver is never null, so the safe access is unnecessary."
+    »1?.toString«();
+    // $TEST$ no info "The receiver is never null, so the safe access is unnecessary."
+    »null?.toString«();
+    // $TEST$ no info "The receiver is never null, so the safe access is unnecessary."
+    »unresolved?.toString«();
+}

tests/resources/validation/style/unnecessary type argument list/main.sdstest

@@ -0,0 +1,49 @@
+package tests.validation.style.unnecessaryTypeArgumentList
+
+class ClassWithoutTypeParameterList
+class ClassWithEmptyTypeParameterList<>
+class ClassWithTypeParameters<T>
+
+enum Enum {
+    EnumVariantWithoutTypeParameterList
+    EnumVariantWithEmptyTypeParameterList<>
+    VariantWithTypeParameters<T>
+}
+
+fun myFunction(
+    // $TEST$ info "This type argument list can be removed."
+    a1: ClassWithoutTypeParameterList»<>«,
+    // $TEST$ no info "This type argument list can be removed."
+    a2: ClassWithoutTypeParameterList»<Int>«,
+    // $TEST$ info "This type argument list can be removed."
+    a3: ClassWithEmptyTypeParameterList»<>«,
+    // $TEST$ no info "This type argument list can be removed."
+    a4: ClassWithEmptyTypeParameterList»<Int>«,
+    // $TEST$ no info "This type argument list can be removed."
+    a5: ClassWithTypeParameters»<>«,
+    // $TEST$ no info "This type argument list can be removed."
+    a6: ClassWithTypeParameters»<Int>«,
+
+    // $TEST$ info "This type argument list can be removed."
+    b1: Enum.EnumVariantWithoutTypeParameterList»<>«,
+    // $TEST$ no info "This type argument list can be removed."
+    b2: Enum.EnumVariantWithoutTypeParameterList»<Int>«,
+    // $TEST$ info "This type argument list can be removed."
+    b3: Enum.EnumVariantWithEmptyTypeParameterList»<>«,
+    // $TEST$ no info "This type argument list can be removed."
+    b4: Enum.EnumVariantWithEmptyTypeParameterList»<Int>«,
+    // $TEST$ no info "This type argument list can be removed."
+    b5: Enum.VariantWithTypeParameters»<>«,
+    // $TEST$ no info "This type argument list can be removed."
+    b6: Enum.VariantWithTypeParameters»<Int>«,
+
+    // $TEST$ info "This type argument list can be removed."
+    c1: Enum»<>«,
+    // $TEST$ no info "This type argument list can be removed."
+    c2: Enum»<Int>«,
+
+    // $TEST$ no info "This type argument list can be removed."
+    d1: Unresolved»<>«,
+    // $TEST$ no info "This type argument list can be removed."
+    d2: Unresolved»<Int>«,
+)