feat: only show this error for the last argument

packages/safe-ds-lang/src/language/validation/other/expressions/arguments.ts

@@ -1,27 +1,38 @@
 import { SafeDsServices } from '../../../safe-ds-module.js';
-import type { SdsArgument } from '../../../generated/ast.js';
+import type { SdsArgumentList } from '../../../generated/ast.js';
 import { ValidationAcceptor } from 'langium';
-import { Argument, Parameter } from '../../../helpers/nodeProperties.js';
+import { Argument, getArguments, Parameter } from '../../../helpers/nodeProperties.js';
 
 export const CODE_ARGUMENT_POSITIONAL = 'argument/positional';
 
 export const argumentMustBeNamedIfParameterIsOptional = (services: SafeDsServices) => {
     const locator = services.workspace.AstNodeLocator;
     const nodeMapper = services.helpers.NodeMapper;
 
-    return (node: SdsArgument, accept: ValidationAcceptor) => {
-        const parameter = nodeMapper.argumentToParameter(node);
-        if (!parameter || !Parameter.isOptional(parameter)) {
-            return;
-        }
+    return (node: SdsArgumentList, accept: ValidationAcceptor) => {
+        for (const argument of getArguments(node).reverse()) {
+            const parameter = nodeMapper.argumentToParameter(argument);
+            if (!parameter) {
+                // Still keep going if there are extra arguments.
+                continue;
+            }
+            if (Parameter.isRequired(parameter)) {
+                // Required parameters must appear before optional parameters.
+                return;
+            }
+
+            if (!Argument.isNamed(argument)) {
+                accept('error', 'Argument must be named if the parameter is optional.', {
+                    node: argument,
+                    property: 'value',
+                    code: CODE_ARGUMENT_POSITIONAL,
+                    data: { path: locator.getAstNodePath(node) },
+                });
 
-        if (!Argument.isNamed(node)) {
-            accept('error', 'Argument must be named if the parameter is optional.', {
-                node,
-                property: 'value',
-                code: CODE_ARGUMENT_POSITIONAL,
-                data: { path: locator.getAstNodePath(node) },
-            });
+                // Only show the error for the last argument. If users added names starting in the middle, we would no
+                // longer be able to assign the arguments to the correct parameters.
+                return;
+            }
         }
     };
 };

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

@@ -222,11 +222,11 @@ export const registerValidationChecks = function (services: SafeDsServices) {
         SdsArgument: [
             argumentCorrespondingParameterShouldNotBeDeprecated(services),
             argumentCorrespondingParameterShouldNotBeExperimental(services),
-            argumentMustBeNamedIfParameterIsOptional(services),
         ],
         SdsArgumentList: [
             argumentListMustNotHavePositionalArgumentsAfterNamedArguments,
             argumentListMustNotSetParameterMultipleTimes(services),
+            argumentMustBeNamedIfParameterIsOptional(services),
         ],
         SdsAssignee: [
             assigneeAssignedResultShouldNotBeDeprecated(services),

packages/safe-ds-lang/tests/resources/validation/other/expressions/arguments/must be named if parameter is optional/annotation calls.sdsdev

@@ -1,19 +1,22 @@
 package tests.validation.other.expressions.arguments.mustBeNamedIfParameterIsOptional
 
 @Repeatable
-annotation MyAnnotation(required: Int, optional: Int = 0)
+annotation MyAnnotation(required: Int, optional1: Int = 0, optional2: Int = 0)
 
 // $TEST$ no error "Argument must be named if the parameter is optional."
 // $TEST$ error "Argument must be named if the parameter is optional."
 @MyAnnotation(»1«, »2«)
 // $TEST$ no error "Argument must be named if the parameter is optional."
 // $TEST$ no error "Argument must be named if the parameter is optional."
-@MyAnnotation(»required = 1«, »optional = 2«)
+// $TEST$ error "Argument must be named if the parameter is optional."
+// $TEST$ no error "Argument must be named if the parameter is optional."
+@MyAnnotation(»1«, »2«, »3«, »4«)
+// $TEST$ no error "Argument must be named if the parameter is optional."
+// $TEST$ no error "Argument must be named if the parameter is optional."
+@MyAnnotation(»required = 1«, »optional1 = 2«)
 
 // $TEST$ no error "Argument must be named if the parameter is optional."
 @Unresolved(»1«)
 // $TEST$ no error "Argument must be named if the parameter is optional."
-@MyAnnotation(1, 2, »3«)
-// $TEST$ no error "Argument must be named if the parameter is optional."
 @MyAnnotation(unresolved = »1«)
 pipeline testPipeline {}

packages/safe-ds-lang/tests/resources/validation/other/expressions/arguments/must be named if parameter is optional/calls.sdsdev

@@ -1,19 +1,22 @@
 package tests.validation.other.expressions.arguments.mustBeNamedIfParameterIsOptional
 
-@Pure fun myFunction(required: Int, optional: Int = 0)
+@Pure fun myFunction(required: Int, optional1: Int = 0, optional2: Int = 0)
 
 pipeline testPipeline {
     // $TEST$ no error "Argument must be named if the parameter is optional."
     // $TEST$ error "Argument must be named if the parameter is optional."
     myFunction(»1«, »2«);
     // $TEST$ no error "Argument must be named if the parameter is optional."
     // $TEST$ no error "Argument must be named if the parameter is optional."
-    myFunction(»required = 1«, »optional = 2«);
+    // $TEST$ error "Argument must be named if the parameter is optional."
+    // $TEST$ no error "Argument must be named if the parameter is optional."
+    myFunction(»1«, »2«, »3«, »4«);
+    // $TEST$ no error "Argument must be named if the parameter is optional."
+    // $TEST$ no error "Argument must be named if the parameter is optional."
+    myFunction(»required = 1«, »optional1 = 2«);
 
     // $TEST$ no error "Argument must be named if the parameter is optional."
     unresolved(»1«);
     // $TEST$ no error "Argument must be named if the parameter is optional."
-    myFunction(1, 2, »3«);
-    // $TEST$ no error "Argument must be named if the parameter is optional."
     myFunction(unresolved = »1«);
 }