feat: unique names withing declarations (#575)

Closes partially #543

### Summary of Changes

Ensure that names are unique within declarations. I'll port the checks
for uniqueness on the file level in a future PR.

---------

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

Author: lars-reimann

src/language/ast/checks.ts

@@ -0,0 +1,6 @@
+import { SdsImport } from '../generated/ast.js';
+
+export const isWildcardImport = function (node: SdsImport): boolean {
+    const importedNamespace = node.importedNamespace ?? '';
+    return importedNamespace.endsWith('*');
+};

src/language/ast/shortcuts.ts

@@ -0,0 +1,96 @@
+import {
+    isSdsAssignment,
+    isSdsBlockLambdaResult,
+    isSdsDeclaration,
+    isSdsPlaceholder,
+    SdsAnnotatedObject,
+    SdsAnnotationCall,
+    SdsAssignee,
+    SdsAssignment,
+    SdsBlock,
+    SdsBlockLambda,
+    SdsBlockLambdaResult,
+    SdsClass,
+    SdsClassMember,
+    SdsEnum,
+    SdsEnumVariant,
+    SdsLiteral,
+    SdsLiteralType,
+    SdsParameter,
+    SdsParameterList,
+    SdsPlaceholder,
+    SdsResult,
+    SdsResultList,
+    SdsStatement,
+    SdsTypeArgument,
+    SdsTypeArgumentList,
+    SdsTypeParameter,
+    SdsTypeParameterList,
+} from '../generated/ast.js';
+import { stream } from 'langium';
+
+export const annotationCallsOrEmpty = function (node: SdsAnnotatedObject | undefined): SdsAnnotationCall[] {
+    if (!node) {
+        /* c8 ignore next 2 */
+        return [];
+    }
+
+    if (isSdsDeclaration(node)) {
+        return node?.annotationCallList?.annotationCalls ?? node?.annotationCalls ?? [];
+    } else {
+        /* c8 ignore next 2 */
+        return node?.annotationCalls ?? [];
+    }
+};
+
+export const assigneesOrEmpty = function (node: SdsAssignment | undefined): SdsAssignee[] {
+    return node?.assigneeList?.assignees ?? [];
+};
+
+export const blockLambdaResultsOrEmpty = function (node: SdsBlockLambda | undefined): SdsBlockLambdaResult[] {
+    return stream(statementsOrEmpty(node?.body))
+        .filter(isSdsAssignment)
+        .flatMap(assigneesOrEmpty)
+        .filter(isSdsBlockLambdaResult)
+        .toArray();
+};
+
+export const literalsOrEmpty = function (node: SdsLiteralType | undefined): SdsLiteral[] {
+    return node?.literalList?.literals ?? [];
+};
+
+export const classMembersOrEmpty = function (node: SdsClass | undefined): SdsClassMember[] {
+    return node?.body?.members ?? [];
+};
+
+export const parametersOrEmpty = function (node: SdsParameterList | undefined): SdsParameter[] {
+    return node?.parameters ?? [];
+};
+
+export const placeholdersOrEmpty = function (node: SdsBlock | undefined): SdsPlaceholder[] {
+    return stream(statementsOrEmpty(node))
+        .filter(isSdsAssignment)
+        .flatMap(assigneesOrEmpty)
+        .filter(isSdsPlaceholder)
+        .toArray();
+};
+
+export const resultsOrEmpty = function (node: SdsResultList | undefined): SdsResult[] {
+    return node?.results ?? [];
+};
+
+export const statementsOrEmpty = function (node: SdsBlock | undefined): SdsStatement[] {
+    return node?.statements ?? [];
+};
+
+export const typeArgumentsOrEmpty = function (node: SdsTypeArgumentList | undefined): SdsTypeArgument[] {
+    return node?.typeArguments ?? [];
+};
+
+export const typeParametersOrEmpty = function (node: SdsTypeParameterList | undefined): SdsTypeParameter[] {
+    return node?.typeParameters ?? [];
+};
+
+export const variantsOrEmpty = function (node: SdsEnum | undefined): SdsEnumVariant[] {
+    return node?.body?.variants ?? [];
+};

src/language/formatting/safe-ds-formatter.ts

@@ -1,7 +1,16 @@
-import { AbstractFormatter, AstNode, CstNode, findCommentNode, Formatting, isAstNode, FormattingAction, FormattingActionOptions } from 'langium';
+import {
+    AbstractFormatter,
+    AstNode,
+    CstNode,
+    findCommentNode,
+    Formatting,
+    isAstNode,
+    FormattingAction,
+    FormattingActionOptions,
+} from 'langium';
 import * as ast from '../generated/ast.js';
 import { SdsImport, SdsImportAlias, SdsModule } from '../generated/ast.js';
-import { annotationCallsOrEmpty, literalsOrEmpty, typeArgumentsOrEmpty } from '../helpers/astShortcuts.js';
+import { annotationCallsOrEmpty, literalsOrEmpty, typeArgumentsOrEmpty } from '../ast/shortcuts.js';
 import noSpace = Formatting.noSpace;
 import newLine = Formatting.newLine;
 import newLines = Formatting.newLines;
@@ -876,6 +885,7 @@ export class SafeDsFormatter extends AbstractFormatter {
         } else if (ast.isSdsUnionType(node)) {
             return typeArgumentsOrEmpty(node.typeArgumentList).length > 0;
         } else {
+            /* c8 ignore next 2 */
             return false;
         }
     }

src/language/grammar/safe-ds.langium

@@ -81,7 +81,7 @@ QualifiedName returns string:
 
 interface SdsModuleMember extends SdsDeclaration {}
 
-SdsAnnotatedModuleMember returns SdsAnnotatedObject:
+SdsAnnotatedModuleMember returns SdsModuleMember:
     {SdsAnnotationCallList}
     annotationCalls+=SdsAnnotationCall+
     (
@@ -108,7 +108,7 @@ SdsAnnotatedModuleMember returns SdsAnnotatedObject:
     )
 ;
 
-SdsUnannotatedModuleMember returns SdsAnnotatedObject:
+SdsUnannotatedModuleMember returns SdsModuleMember:
       {SdsAnnotation}
       SdsAnnotationFragment
 
@@ -170,7 +170,7 @@ SdsParentTypeList returns SdsParentTypeList:
 ;
 
 interface SdsClassBody extends SdsObject {
-	members: SdsAnnotatedObject[]
+	members: SdsClassMember[]
 }
 
 SdsClassBody returns SdsClassBody:
@@ -179,12 +179,12 @@ SdsClassBody returns SdsClassBody:
 
 interface SdsClassMember extends SdsDeclaration {}
 
-SdsClassMember returns SdsAnnotatedObject:
+SdsClassMember returns SdsClassMember:
     SdsAnnotatedClassMember
   | SdsUnannotatedClassMember
 ;
 
-SdsAnnotatedClassMember returns SdsAnnotatedObject:
+SdsAnnotatedClassMember returns SdsClassMember:
     {SdsAnnotationCallList}
     annotationCalls+=SdsAnnotationCall+
     (
@@ -203,7 +203,7 @@ SdsAnnotatedClassMember returns SdsAnnotatedObject:
     )
 ;
 
-SdsUnannotatedClassMember returns SdsAnnotatedObject:
+SdsUnannotatedClassMember returns SdsClassMember:
       {SdsAttribute}
       SdsAttributeFragment
 

src/language/helpers/astShortcuts.ts

@@ -12,7 +12,7 @@ import {
     SdsType,
     SdsYield,
 } from '../generated/ast.js';
-import { resultsOrEmpty } from '../helpers/astShortcuts.js';
+import { resultsOrEmpty } from '../ast/shortcuts.js';
 
 export class SafeDsScopeProvider extends DefaultScopeProvider {
     override getScope(context: ReferenceInfo): Scope {

src/language/scoping/safe-ds-scope-provider.ts

@@ -1,6 +1,6 @@
 import { ValidationAcceptor } from 'langium';
 import { SdsImportAlias } from '../generated/ast.js';
-import { isWildcardImport } from '../helpers/astShortcuts.js';
+import { isWildcardImport } from '../ast/checks.js';
 
 export const CODE_IMPORT_WILDCARD_IMPORT_WITH_ALIAS = 'import/wildcard-import-with-alias';