Prevent cross-script module slot aliasing

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

@@ -108,11 +108,7 @@ class Script(
             seedImportBindings(scope, seedScope)
         }
         if (moduleSlotPlan.isNotEmpty()) {
-            scope.applySlotPlan(moduleSlotPlan)
+            installModuleSlotPlan(scope)
-            for (name in moduleSlotPlan.keys) {
-                val record = scope.objects[name] ?: scope.localBindings[name] ?: continue
-                scope.updateSlotFor(name, record)
-            }
         }
     }
 
@@ -120,12 +116,26 @@ class Script(
         if (importBindings.isEmpty() && importedModules.isEmpty()) return
         seedImportBindings(scope, seedScope)
         if (moduleSlotPlan.isNotEmpty()) {
-            scope.applySlotPlan(moduleSlotPlan)
+            installModuleSlotPlan(scope)
-            for (name in moduleSlotPlan.keys) {
+        }
-                val record = scope.objects[name] ?: scope.localBindings[name] ?: continue
+    }
-                scope.updateSlotFor(name, record)
+
+    private fun installModuleSlotPlan(scope: Scope) {
+        for ((name, index) in moduleSlotPlan) {
+            if (scope.getSlotIndexOf(name) != null) continue
+            if (scope.hasSlotPlanConflict(mapOf(name to index))) {
+                val record = scope.objects[name]
+                    ?: scope.localBindings[name]
+                    ?: ObjRecord(ObjUnset, isMutable = true)
+                scope.allocateSlotFor(name, record)
+            } else {
+                scope.applySlotPlan(mapOf(name to index))
             }
         }
+        for (name in moduleSlotPlan.keys) {
+            val record = scope.objects[name] ?: scope.localBindings[name] ?: continue
+            scope.updateSlotFor(name, record)
+        }
     }
 
     private suspend fun seedModuleLocals(

lynglib/src/commonMain/kotlin/net/sergeych/lyng/bytecode/CmdRuntime.kt

@@ -5654,6 +5654,14 @@ class CmdFrame(
             if (index < target.slotCount) return index
             return index
         }
+        if (target.hasSlotPlanConflict(mapOf(name to index))) {
+            val record = target.getLocalRecordDirect(name)
+                ?: target.localBindings[name]
+                ?: target.parent?.get(name)
+                ?: target.get(name)
+                ?: ObjRecord(ObjUnset, isMutable = true)
+            return target.allocateSlotFor(name, record)
+        }
         target.applySlotPlan(mapOf(name to index))
         val existing = target.getLocalRecordDirect(name) ?: target.localBindings[name]
         if (existing != null) {

lynglib/src/commonTest/kotlin/CompilerVmReviewRegressionTest.kt

@@ -150,6 +150,37 @@ class CompilerVmReviewRegressionTest {
         assertEquals(42, callable.call(scope, ObjInt.of(40)).toInt())
     }
 
+    @Test
+    fun preparedLambdaKeepsImmutableModuleCaptureAcrossOtherScriptsInSameScope() = runTest {
+        val unaryLambda = Compiler.compile(
+            Source(
+                "<cross-script-capture-unary>",
+                """
+                val delta = 2
+                { x -> x + delta }
+                """.trimIndent()
+            ),
+            Script.defaultImportManager
+        )
+        val unrelatedScript = Compiler.compile(
+            Source(
+                "<cross-script-capture-unrelated>",
+                """
+                val base = 7
+                base
+                """.trimIndent()
+            ),
+            Script.defaultImportManager
+        )
+
+        val scope = Script.newScope()
+        val callable = unaryLambda.execute(scope) as Statement
+        unrelatedScript.execute(scope)
+
+        assertEquals(42, callable.call(scope, ObjInt.of(40)).toInt())
+        assertEquals(42, scope.asFacade().call(callable, Arguments(ObjInt.of(40))).toInt())
+    }
+
     @Test
     fun subjectlessWhenReportsScriptError() = runTest {
         val ex = assertFailsWith<ScriptError> {