feat: error if wildcard import has alias (#574)

Closes partially #543

### Summary of Changes

Show an error if a wildcard import has an alias.

---------

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

Author: lars-reimann

src/language/helpers/astShortcuts.ts

@@ -3,8 +3,11 @@ import {
     isSdsDeclaration,
     SdsAnnotatedObject,
     SdsAnnotationCall,
+    SdsImport,
     SdsLiteral,
-    SdsLiteralType, SdsResult, SdsResultList,
+    SdsLiteralType,
+    SdsResult,
+    SdsResultList,
     SdsTypeArgument,
     SdsTypeArgumentList,
 } from '../generated/ast.js';
@@ -23,8 +26,13 @@ export const literalsOrEmpty = function (node: SdsLiteralType | undefined): SdsL
 
 export const resultsOrEmpty = function (node: SdsResultList | undefined): SdsResult[] {
     return node?.results ?? [];
-}
+};
 
 export const typeArgumentsOrEmpty = function (node: SdsTypeArgumentList | undefined): SdsTypeArgument[] {
     return node?.typeArguments ?? [];
 };
+
+export const isWildcardImport = function (node: SdsImport): boolean {
+    const importedNamespace = node.importedNamespace ?? '';
+    return importedNamespace.endsWith('*');
+};

src/language/validation/imports.ts

@@ -0,0 +1,16 @@
+import { ValidationAcceptor } from 'langium';
+import { SdsImportAlias } from '../generated/ast.js';
+import { isWildcardImport } from '../helpers/astShortcuts.js';
+
+export const CODE_IMPORT_WILDCARD_IMPORT_WITH_ALIAS = 'import/wildcard-import-with-alias';
+
+export const importAliasMustNotBeUsedForWildcardImports = (node: SdsImportAlias, accept: ValidationAcceptor): void => {
+    const importNode = node.$container;
+
+    if (importNode && isWildcardImport(importNode)) {
+        accept('error', 'A wildcard import must not have an alias.', {
+            node,
+            code: CODE_IMPORT_WILDCARD_IMPORT_WITH_ALIAS,
+        });
+    }
+};

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

@@ -24,6 +24,7 @@ import {
     parameterListMustNotHaveRequiredParametersAfterOptionalParameters,
     parameterListVariadicParameterMustBeLast,
 } from './other/declarations/parameterLists.js';
+import { importAliasMustNotBeUsedForWildcardImports } from './imports.js';
 
 /**
  * Register custom validation checks.
@@ -41,6 +42,7 @@ export const registerValidationChecks = function (services: SafeDsServices) {
         SdsEnumBody: [enumBodyShouldNotBeEmpty],
         SdsEnumVariant: [enumVariantParameterListShouldNotBeEmpty],
         SdsFunction: [functionResultListShouldNotBeEmpty],
+        SdsImportAlias: [importAliasMustNotBeUsedForWildcardImports],
         SdsModule: [moduleDeclarationsMustMatchFileKind, moduleWithDeclarationsMustStatePackage],
         SdsParameter: [parameterMustHaveTypeHint],
         SdsParameterList: [

tests/resources/validation/other/imports/wildcard import must not have alias/main.sdstest

@@ -0,0 +1,6 @@
+package tests.validation.other.modules.wildcardImportMustNotHaveAlias
+
+// $TEST$ error "A wildcard import must not have an alias."
+import stuff.* »as S«
+// $TEST$ no error "A wildcard import must not have an alias."
+import stuff.Stuff »as S«