feat: type checking (#723)

Closes #666

### Summary of Changes

Show validation errors if types don't match.

packages/safe-ds-lang/src/language/typing/safe-ds-type-checker.ts

@@ -105,10 +105,7 @@ export class SafeDsTypeChecker {
                 const typeEntry = type.outputType.entries[i];
                 const otherEntry = other.outputType.entries[i];
 
-                // Names must match
-                if (typeEntry.name !== otherEntry.name) {
-                    return false;
-                }
+                // Names must not match since we always fetch results by index
 
                 // Types must be covariant
                 if (!this.isAssignableTo(typeEntry.type, otherEntry.type)) {

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

@@ -44,11 +44,18 @@ import {
     yieldMustNotBeUsedInPipeline,
 } from './other/statements/assignments.js';
 import {
+    argumentTypeMustMatchParameterType,
     attributeMustHaveTypeHint,
     callReceiverMustBeCallable,
+    indexedAccessIndexMustHaveCorrectType,
+    indexedAccessReceiverMustBeListOrMap,
+    infixOperationOperandsMustHaveCorrectType,
     namedTypeMustSetAllTypeParameters,
+    parameterDefaultValueTypeMustMatchParameterType,
     parameterMustHaveTypeHint,
+    prefixOperationOperandMustHaveCorrectType,
     resultMustHaveTypeHint,
+    yieldTypeMustMatchResultType,
 } from './types.js';
 import {
     moduleDeclarationsMustMatchFileKind,
@@ -182,6 +189,7 @@ export const registerValidationChecks = function (services: SafeDsServices) {
         SdsArgument: [
             argumentCorrespondingParameterShouldNotBeDeprecated(services),
             argumentCorrespondingParameterShouldNotBeExperimental(services),
+            argumentTypeMustMatchParameterType(services),
         ],
         SdsArgumentList: [
             argumentListMustNotHavePositionalArgumentsAfterNamedArguments,
@@ -226,8 +234,16 @@ export const registerValidationChecks = function (services: SafeDsServices) {
         ],
         SdsImport: [importPackageMustExist(services), importPackageShouldNotBeEmpty(services)],
         SdsImportedDeclaration: [importedDeclarationAliasShouldDifferFromDeclarationName],
-        SdsIndexedAccess: [indexedAccessesShouldBeUsedWithCaution],
-        SdsInfixOperation: [divisionDivisorMustNotBeZero(services), elvisOperatorShouldBeNeeded(services)],
+        SdsIndexedAccess: [
+            indexedAccessIndexMustHaveCorrectType(services),
+            indexedAccessReceiverMustBeListOrMap(services),
+            indexedAccessesShouldBeUsedWithCaution,
+        ],
+        SdsInfixOperation: [
+            divisionDivisorMustNotBeZero(services),
+            elvisOperatorShouldBeNeeded(services),
+            infixOperationOperandsMustHaveCorrectType(services),
+        ],
         SdsLambda: [
             lambdaMustBeAssignedToTypedParameter(services),
             lambdaParametersMustNotBeAnnotated,
@@ -266,12 +282,14 @@ export const registerValidationChecks = function (services: SafeDsServices) {
         SdsParameter: [
             constantParameterMustHaveConstantDefaultValue(services),
             parameterMustHaveTypeHint,
+            parameterDefaultValueTypeMustMatchParameterType(services),
             requiredParameterMustNotBeDeprecated(services),
             requiredParameterMustNotBeExpert(services),
         ],
         SdsParameterList: [parameterListMustNotHaveRequiredParametersAfterOptionalParameters],
         SdsPipeline: [pipelineMustContainUniqueNames],
         SdsPlaceholder: [placeholdersMustNotBeAnAlias, placeholderShouldBeUsed(services)],
+        SdsPrefixOperation: [prefixOperationOperandMustHaveCorrectType(services)],
         SdsReference: [
             referenceMustNotBeFunctionPointer,
             referenceMustNotBeStaticClassOrEnumReference,
@@ -299,7 +317,7 @@ export const registerValidationChecks = function (services: SafeDsServices) {
             unionTypeShouldNotHaveDuplicateTypes(services),
             unionTypeShouldNotHaveASingularTypeArgument,
         ],
-        SdsYield: [yieldMustNotBeUsedInPipeline],
+        SdsYield: [yieldMustNotBeUsedInPipeline, yieldTypeMustMatchResultType(services)],
     };
     registry.register(checks);
 };

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

@@ -8,25 +8,55 @@ import {
     isSdsPipeline,
     isSdsReference,
     isSdsSchema,
+    SdsArgument,
     SdsAttribute,
     SdsCall,
+    SdsIndexedAccess,
+    SdsInfixOperation,
     SdsNamedType,
     SdsParameter,
+    SdsPrefixOperation,
     SdsResult,
+    SdsYield,
 } from '../generated/ast.js';
 import { getTypeArguments, getTypeParameters } from '../helpers/nodeProperties.js';
 import { SafeDsServices } from '../safe-ds-module.js';
 import { pluralize } from '../../helpers/stringUtils.js';
 import { isEmpty } from '../../helpers/collectionUtils.js';
 
 export const CODE_TYPE_CALLABLE_RECEIVER = 'type/callable-receiver';
+export const CODE_TYPE_MISMATCH = 'type/mismatch';
 export const CODE_TYPE_MISSING_TYPE_ARGUMENTS = 'type/missing-type-arguments';
 export const CODE_TYPE_MISSING_TYPE_HINT = 'type/missing-type-hint';
 
 // -----------------------------------------------------------------------------
 // Type checking
 // -----------------------------------------------------------------------------
 
+export const argumentTypeMustMatchParameterType = (services: SafeDsServices) => {
+    const nodeMapper = services.helpers.NodeMapper;
+    const typeChecker = services.types.TypeChecker;
+    const typeComputer = services.types.TypeComputer;
+
+    return (node: SdsArgument, accept: ValidationAcceptor) => {
+        const parameter = nodeMapper.argumentToParameter(node);
+        if (!parameter) {
+            return;
+        }
+
+        const argumentType = typeComputer.computeType(node);
+        const parameterType = typeComputer.computeType(parameter);
+
+        if (!typeChecker.isAssignableTo(argumentType, parameterType)) {
+            accept('error', `Expected type '${parameterType}' but got '${argumentType}'.`, {
+                node,
+                property: 'value',
+                code: CODE_TYPE_MISMATCH,
+            });
+        }
+    };
+};
+
 export const callReceiverMustBeCallable = (services: SafeDsServices) => {
     const nodeMapper = services.helpers.NodeMapper;
 
@@ -60,6 +90,187 @@ export const callReceiverMustBeCallable = (services: SafeDsServices) => {
     };
 };
 
+export const indexedAccessReceiverMustBeListOrMap = (services: SafeDsServices) => {
+    const coreTypes = services.types.CoreTypes;
+    const typeChecker = services.types.TypeChecker;
+    const typeComputer = services.types.TypeComputer;
+
+    return (node: SdsIndexedAccess, accept: ValidationAcceptor): void => {
+        const receiverType = typeComputer.computeType(node.receiver);
+        if (
+            !typeChecker.isAssignableTo(receiverType, coreTypes.List) &&
+            !typeChecker.isAssignableTo(receiverType, coreTypes.Map)
+        ) {
+            accept('error', `Expected type '${coreTypes.List}' or '${coreTypes.Map}' but got '${receiverType}'.`, {
+                node: node.receiver,
+                code: CODE_TYPE_MISMATCH,
+            });
+        }
+    };
+};
+
+export const indexedAccessIndexMustHaveCorrectType = (services: SafeDsServices) => {
+    const coreTypes = services.types.CoreTypes;
+    const typeChecker = services.types.TypeChecker;
+    const typeComputer = services.types.TypeComputer;
+
+    return (node: SdsIndexedAccess, accept: ValidationAcceptor): void => {
+        const receiverType = typeComputer.computeType(node.receiver);
+        if (typeChecker.isAssignableTo(receiverType, coreTypes.List)) {
+            const indexType = typeComputer.computeType(node.index);
+            if (!typeChecker.isAssignableTo(indexType, coreTypes.Int)) {
+                accept('error', `Expected type '${coreTypes.Int}' but got '${indexType}'.`, {
+                    node,
+                    property: 'index',
+                    code: CODE_TYPE_MISMATCH,
+                });
+            }
+        }
+    };
+};
+
+export const infixOperationOperandsMustHaveCorrectType = (services: SafeDsServices) => {
+    const coreTypes = services.types.CoreTypes;
+    const typeChecker = services.types.TypeChecker;
+    const typeComputer = services.types.TypeComputer;
+
+    return (node: SdsInfixOperation, accept: ValidationAcceptor): void => {
+        const leftType = typeComputer.computeType(node.leftOperand);
+        const rightType = typeComputer.computeType(node.rightOperand);
+        switch (node.operator) {
+            case 'or':
+            case 'and':
+                if (!typeChecker.isAssignableTo(leftType, coreTypes.Boolean)) {
+                    accept('error', `Expected type '${coreTypes.Boolean}' but got '${leftType}'.`, {
+                        node: node.leftOperand,
+                        code: CODE_TYPE_MISMATCH,
+                    });
+                }
+                if (!typeChecker.isAssignableTo(rightType, coreTypes.Boolean)) {
+                    accept('error', `Expected type '${coreTypes.Boolean}' but got '${rightType}'.`, {
+                        node: node.rightOperand,
+                        code: CODE_TYPE_MISMATCH,
+                    });
+                }
+                return;
+            case '<':
+            case '<=':
+            case '>=':
+            case '>':
+            case '+':
+            case '-':
+            case '*':
+            case '/':
+                if (
+                    !typeChecker.isAssignableTo(leftType, coreTypes.Float) &&
+                    !typeChecker.isAssignableTo(leftType, coreTypes.Int)
+                ) {
+                    accept('error', `Expected type '${coreTypes.Float}' or '${coreTypes.Int}' but got '${leftType}'.`, {
+                        node: node.leftOperand,
+                        code: CODE_TYPE_MISMATCH,
+                    });
+                }
+                if (
+                    !typeChecker.isAssignableTo(rightType, coreTypes.Float) &&
+                    !typeChecker.isAssignableTo(rightType, coreTypes.Int)
+                ) {
+                    accept(
+                        'error',
+                        `Expected type '${coreTypes.Float}' or '${coreTypes.Int}' but got '${rightType}'.`,
+                        {
+                            node: node.rightOperand,
+                            code: CODE_TYPE_MISMATCH,
+                        },
+                    );
+                }
+                return;
+        }
+    };
+};
+
+export const parameterDefaultValueTypeMustMatchParameterType = (services: SafeDsServices) => {
+    const typeChecker = services.types.TypeChecker;
+    const typeComputer = services.types.TypeComputer;
+
+    return (node: SdsParameter, accept: ValidationAcceptor) => {
+        const defaultValue = node.defaultValue;
+        if (!defaultValue) {
+            return;
+        }
+
+        const defaultValueType = typeComputer.computeType(defaultValue);
+        const parameterType = typeComputer.computeType(node);
+
+        if (!typeChecker.isAssignableTo(defaultValueType, parameterType)) {
+            accept('error', `Expected type '${parameterType}' but got '${defaultValueType}'.`, {
+                node,
+                property: 'defaultValue',
+                code: CODE_TYPE_MISMATCH,
+            });
+        }
+    };
+};
+
+export const prefixOperationOperandMustHaveCorrectType = (services: SafeDsServices) => {
+    const coreTypes = services.types.CoreTypes;
+    const typeChecker = services.types.TypeChecker;
+    const typeComputer = services.types.TypeComputer;
+
+    return (node: SdsPrefixOperation, accept: ValidationAcceptor): void => {
+        const operandType = typeComputer.computeType(node.operand);
+        switch (node.operator) {
+            case 'not':
+                if (!typeChecker.isAssignableTo(operandType, coreTypes.Boolean)) {
+                    accept('error', `Expected type '${coreTypes.Boolean}' but got '${operandType}'.`, {
+                        node,
+                        property: 'operand',
+                        code: CODE_TYPE_MISMATCH,
+                    });
+                }
+                return;
+            case '-':
+                if (
+                    !typeChecker.isAssignableTo(operandType, coreTypes.Float) &&
+                    !typeChecker.isAssignableTo(operandType, coreTypes.Int)
+                ) {
+                    accept(
+                        'error',
+                        `Expected type '${coreTypes.Float}' or '${coreTypes.Int}' but got '${operandType}'.`,
+                        {
+                            node,
+                            property: 'operand',
+                            code: CODE_TYPE_MISMATCH,
+                        },
+                    );
+                }
+                return;
+        }
+    };
+};
+
+export const yieldTypeMustMatchResultType = (services: SafeDsServices) => {
+    const typeChecker = services.types.TypeChecker;
+    const typeComputer = services.types.TypeComputer;
+
+    return (node: SdsYield, accept: ValidationAcceptor) => {
+        const result = node.result?.ref;
+        if (!result) {
+            return;
+        }
+
+        const yieldType = typeComputer.computeType(node);
+        const resultType = typeComputer.computeType(result);
+
+        if (!typeChecker.isAssignableTo(yieldType, resultType)) {
+            accept('error', `Expected type '${resultType}' but got '${yieldType}'.`, {
+                node,
+                property: 'result',
+                code: CODE_TYPE_MISMATCH,
+            });
+        }
+    };
+};
+
 // -----------------------------------------------------------------------------
 // Missing type arguments
 // -----------------------------------------------------------------------------

packages/safe-ds-lang/tests/language/typing/safe-ds-type-checker.test.ts

@@ -144,7 +144,7 @@ describe('SafeDsTypeChecker', async () => {
         {
             type1: callableType8,
             type2: callableType7,
-            expected: false,
+            expected: true,
         },
         {
             type1: callableType9,

packages/safe-ds-lang/tests/language/validation/creator.ts

@@ -6,7 +6,7 @@ import fs from 'fs';
 import { findTestChecks } from '../../helpers/testChecks.js';
 import { getSyntaxErrors, SyntaxErrorsInCodeError } from '../../helpers/diagnostics.js';
 import { EmptyFileSystem, URI } from 'langium';
-import { createSafeDsServices } from '../../../src/language/safe-ds-module.js';
+import { createSafeDsServices } from '../../../src/language/index.js';
 import { Range } from 'vscode-languageserver';
 import { TestDescription, TestDescriptionError } from '../../helpers/testDescription.js';
 
@@ -40,7 +40,7 @@ const createValidationTest = async (parentDirectory: URI, uris: URI[]): Promise<
         }
 
         for (const check of checksResult.value) {
-            const regex = /\s*(?<isAbsent>no\s+)?(?<severity>\S+)\s*(?:(?<messageIsRegex>r)?"(?<message>[^"]*)")?/gu;
+            const regex = /\s*(?<isAbsent>no\s+)?(?<severity>\S+)\s*(?:(?<messageIsRegex>r)?"(?<message>.*)")?/gu;
             const match = regex.exec(check.comment);
 
             // Overall comment is invalid

packages/safe-ds-lang/tests/resources/generation/declarations/parameter with python name/input.sdstest

@@ -4,6 +4,6 @@ fun f1(param: (a: Int, b: Int, c: Int) -> r: Int)
 fun f2(param: (a: Int, b: Int, c: Int) -> ())
 
 segment test(param1: Int, @PythonName("param_2") param2: Int, @PythonName("param_3") param3: Int = 0) {
-    f1((param1: Int, param2: Int, param3: Int = 0) -> 1);
-    f2((param1: Int, param2: Int, param3: Int = 0) {});
+    f1((a: Int, b: Int, c: Int = 0) -> 1);
+    f2((a: Int, b: Int, c: Int = 0) {});
 }

packages/safe-ds-lang/tests/resources/generation/declarations/parameter with python name/output/tests/generator/parameterWithPythonName/gen_input.py

@@ -1,7 +1,7 @@
 # Segments ---------------------------------------------------------------------
 
 def test(param1, param_2, param_3=0):
-    f1(lambda param1, param2, param3=0: 1)
-    def __gen_block_lambda_0(param1, param2, param3=0):
+    f1(lambda a, b, c=0: 1)
+    def __gen_block_lambda_0(a, b, c=0):
         pass
     f2(__gen_block_lambda_0)

packages/safe-ds-lang/tests/resources/generation/expressions/block lambda/input.sdstest

@@ -9,7 +9,7 @@ pipeline test {
     f1((a: Int, b: Int = 2) {
         yield d = g();
     });
-    f1((a: Int, c: Int) {
+    f1((a: Int, b: Int) {
         yield d = g();
     });
     f2(() {});

packages/safe-ds-lang/tests/resources/generation/expressions/block lambda/output/tests/generator/blockLambda/gen_input.py

@@ -5,7 +5,7 @@ def __gen_block_lambda_0(a, b=2):
         __gen_block_lambda_result_d = g()
         return __gen_block_lambda_result_d
     f1(__gen_block_lambda_0)
-    def __gen_block_lambda_1(a, c):
+    def __gen_block_lambda_1(a, b):
         __gen_block_lambda_result_d = g()
         return __gen_block_lambda_result_d
     f1(__gen_block_lambda_1)