From 1277bd1f5efe4cf9532d03b656d26b026428b461 Mon Sep 17 00:00:00 2001
From: Lars Reimann <mail@larsreimann.com>
Date: Sat, 17 Feb 2024 12:51:48 +0100
Subject: [PATCH] feat: scoping for member accesses if receiver has type
 parameter type (#889)

### Summary of Changes

The scope provider can now handle member accesses where the receiver has
type parameter type. This type is replaced by its upper bound, before
name resolution continues as before.
---
 .../scoping/safe-ds-scope-provider.ts         |  4 ++-
 .../on type parameters/main.sdstest           | 29 +++++++++++++++++++
 2 files changed, 32 insertions(+), 1 deletion(-)
 create mode 100644 packages/safe-ds-lang/tests/resources/scoping/member accesses/on type parameters/main.sdstest

diff --git a/packages/safe-ds-lang/src/language/scoping/safe-ds-scope-provider.ts b/packages/safe-ds-lang/src/language/scoping/safe-ds-scope-provider.ts
index a0fd47437..d9b080806 100644
--- a/packages/safe-ds-lang/src/language/scoping/safe-ds-scope-provider.ts
+++ b/packages/safe-ds-lang/src/language/scoping/safe-ds-scope-provider.ts
@@ -71,7 +71,7 @@ import {
 } from '../helpers/nodeProperties.js';
 import { SafeDsNodeMapper } from '../helpers/safe-ds-node-mapper.js';
 import { SafeDsServices } from '../safe-ds-module.js';
-import { ClassType, EnumVariantType, LiteralType } from '../typing/model.js';
+import { ClassType, EnumVariantType, LiteralType, TypeParameterType } from '../typing/model.js';
 import type { SafeDsClassHierarchy } from '../typing/safe-ds-class-hierarchy.js';
 import { SafeDsTypeComputer } from '../typing/safe-ds-type-computer.js';
 import { SafeDsPackageManager } from '../workspace/safe-ds-package-manager.js';
@@ -227,6 +227,8 @@ export class SafeDsScopeProvider extends DefaultScopeProvider {
         let receiverType = this.typeComputer.computeType(node.receiver);
         if (receiverType instanceof LiteralType) {
             receiverType = this.typeComputer.computeClassTypeForLiteralType(receiverType);
+        } else if (receiverType instanceof TypeParameterType) {
+            receiverType = this.typeComputer.computeUpperBound(receiverType);
         }
 
         if (receiverType instanceof ClassType) {
diff --git a/packages/safe-ds-lang/tests/resources/scoping/member accesses/on type parameters/main.sdstest b/packages/safe-ds-lang/tests/resources/scoping/member accesses/on type parameters/main.sdstest
new file mode 100644
index 000000000..ee0348077
--- /dev/null
+++ b/packages/safe-ds-lang/tests/resources/scoping/member accesses/on type parameters/main.sdstest	
@@ -0,0 +1,29 @@
+package tests.scoping.memberAccesses.onTypeParameters
+
+class C {
+    // $TEST$ target attribute
+    attr »a«: Int
+}
+
+class MyClass<Unbounded, UpperBound>(
+    unbounded: Unbounded,
+    upperBound: UpperBound,
+
+    // $TEST$ unresolved
+    p1: Any = unbounded.»a«,
+    // $TEST$ references attribute
+    p2: Any = upperBound.»a«,
+) where {
+    UpperBound sub C
+} {
+    attr unbounded: Unbounded
+    attr upperBound: UpperBound
+}
+
+segment mySegment(instance: MyClass<C, C>) {
+    // $TEST$ references attribute
+    instance.unbounded.»a«;
+
+    // $TEST$ references attribute
+    instance.upperBound.»a«;
+}