added Multiple Inheritance

lynglib/src/commonTest/kotlin/MIDiagnosticsTest.kt

@@ -0,0 +1,105 @@
+/*
+ * Copyright 2025 Sergey S. Chernov real.sergeych@gmail.com
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+/*
+ * Diagnostics tests for Multiple Inheritance (MI)
+ */
+
+import kotlinx.coroutines.test.runTest
+import net.sergeych.lyng.eval
+import kotlin.test.Test
+import kotlin.test.assertFails
+import kotlin.test.assertTrue
+
+class MIDiagnosticsTest {
+
+    @Test
+    fun missingMemberIncludesLinearizationAndHint() = runTest {
+        val ex = assertFails {
+            eval(
+                """
+                class Foo(val a) { fun runA() { "ResultA:" + a } }
+                class Bar(val b) { fun runB() { "ResultB:" + b } }
+                class FooBar(a,b) : Foo(a), Bar(b) { }
+                val fb = FooBar(1,2)
+                fb.qux()
+                """.trimIndent()
+            )
+        }
+        val msg = ex.message ?: ""
+        assertTrue(msg.contains("no such member: qux"), "must mention missing member name")
+        assertTrue(msg.contains("FooBar"), "must mention receiver class name")
+        assertTrue(msg.contains("Considered order:"), "must include linearization header")
+        assertTrue(msg.contains("FooBar") && msg.contains("Foo") && msg.contains("Bar"), "must list classes in order")
+        assertTrue(msg.contains("this@") || msg.contains("(obj as"), "must suggest qualification or cast")
+    }
+
+    @Test
+    fun missingFieldIncludesLinearization() = runTest {
+        val ex = assertFails {
+            eval(
+                """
+                class Foo(val a) { var tag = "F" }
+                class Bar(val b) { var tag = "B" }
+                class FooBar(a,b) : Foo(a), Bar(b) { }
+                val fb = FooBar(1,2)
+                fb.unknownField
+                """.trimIndent()
+            )
+        }
+        val msg = ex.message ?: ""
+        assertTrue(msg.contains("no such field: unknownField"))
+        assertTrue(msg.contains("FooBar"))
+        assertTrue(msg.contains("Considered order:"))
+    }
+
+    @Test
+    fun invalidQualifiedThisReportsAncestorError() = runTest {
+        assertFails {
+            eval(
+                """
+                class Foo() { fun f() { "F" } }
+                class Bar() { fun g() { "G" } }
+                class Baz() : Foo() {
+                    fun bad() { this@Bar.g() }
+                }
+                val b = Baz()
+                b.bad()
+                """.trimIndent()
+            )
+        }
+    }
+
+    @Test
+    fun castFailureMentionsActualAndTargetTypes() = runTest {
+        val ex = assertFails {
+            eval(
+                """
+                class Foo() { }
+                class Bar() { }
+                val b = Bar()
+                (b as Foo)
+                """.trimIndent()
+            )
+        }
+        val msg = ex.message ?: ""
+        // message like: Cannot cast Bar to Foo (be tolerant across targets)
+        val lower = msg.lowercase()
+        assertTrue(lower.contains("cast"), "message should mention cast")
+        assertTrue(msg.contains("Bar") || msg.contains("Foo"), "should mention at least one of the types")
+    }
+}