Reject class-named members and unsupported constructor delegation

lynglib/src/commonMain/kotlin/net/sergeych/lyng/Compiler.kt

@@ -7458,6 +7458,14 @@ class Compiler(
         isOptional: Boolean,
         explicitTypeArgs: List<TypeDecl>? = null
     ): ObjRef {
+        val thisTypeName = when (left) {
+            is LocalVarRef -> if (left.name == "this") currentImplicitThisTypeName() else null
+            is QualifiedThisRef -> left.typeName
+            else -> null
+        }
+        if (thisTypeName != null && codeContexts.any { it is CodeContext.ClassBody && it.name == thisTypeName }) {
+            throw ScriptError(cc.currentPos(), "constructor delegation through this is not supported; call the class by name")
+        }
         var detectedBlockArgument = blockArgument
         val expectedReceiver = tailBlockReceiverType(left)
         val expectedTailCallable = expectedCallableArgumentType(left, 0)
@@ -9984,6 +9992,10 @@ class Compiler(
             name = t.value
             nameStartPos = t.pos
         }
+        if (parentContext is CodeContext.ClassBody && extTypeName == null &&
+            name == parentContext.name.substringAfterLast('.')) {
+            throw ScriptError(nameStartPos, "member function cannot have the same name as its enclosing class: $name")
+        }
         val extensionWrapperName = extTypeName?.let { extensionCallableName(it, name) }
         val classCtx = codeContexts.asReversed().firstOrNull { it is CodeContext.ClassBody } as? CodeContext.ClassBody
         var memberMethodId = if (extTypeName == null) classCtx?.memberMethodIds?.get(name) else null

lynglib/src/commonTest/kotlin/ClassNameMemberRegressionTest.kt

@@ -0,0 +1,62 @@
+import kotlinx.coroutines.test.runTest
+import net.sergeych.lyng.ScriptError
+import net.sergeych.lyng.eval
+import kotlin.test.Test
+import kotlin.test.assertContains
+import kotlin.test.assertEquals
+import kotlin.test.assertFailsWith
+
+class ClassNameMemberRegressionTest {
+    @Test
+    fun rejectsClassNamedMembersAtTheirDeclaration() = runTest {
+        for (member in listOf(
+            "fun Same(y): String = y.toString()",
+            "fun Same(y, z): String = y.toString() + z.toString()",
+            "fun Same(y): Same = Same(y * 2)",
+            "static fun Same(y): Same = Same(y)",
+            "fun Same(y): String = \"member\"; fun literal() = Same::class.toString()"
+        )) {
+            val error = assertFailsWith<ScriptError> {
+                eval("class Same(x) {\n    $member\n}")
+            }
+            assertContains(error.errorMessage, "member function cannot have the same name as its enclosing class")
+            assertEquals(1, error.pos.line)
+        }
+    }
+
+    @Test
+    fun thisIsNotConstructorDelegation() = runTest {
+        for (receiver in listOf("this", "this@Factory")) {
+            val error = assertFailsWith<ScriptError> {
+                eval("class Factory(x) { fun again(): Factory = $receiver(x + 1) }")
+            }
+            assertContains(error.errorMessage, "constructor delegation through this is not supported")
+        }
+    }
+
+    @Test
+    fun constructorAndClassLiteralRemainAvailable() = runTest {
+        assertEquals("3", eval("""
+            class Factory(val x: Int) {
+                fun again(y: Int): Factory = Factory(y)
+                fun literal(): String = Factory::class.toString()
+            }
+            val f = Factory(1)
+            f.literal()
+            f.again(3).x.toString()
+        """.trimIndent()).toString())
+    }
+
+    @Test
+    fun localFunctionsCanStillShadowClassNames() = runTest {
+        assertEquals("local 7", eval("""
+            class Local(x) {
+                fun probe(y): String {
+                    fun Local(z): String = "local " + z.toString()
+                    return Local(y)
+                }
+            }
+            Local(1).probe(7)
+        """.trimIndent()).toString())
+    }
+}