Add inspection for missing abstract shadows in enum mixin

Author: Earthcomputer

src/main/kotlin/platform/mixin/action/GenerateShadowAction.kt

@@ -151,7 +151,7 @@ fun createShadowMembers(
     }.toList()
 
     // Make the class abstract (if not already)
-    if (shouldMakeAbstract && !psiClass.hasModifierProperty(PsiModifier.ABSTRACT)) {
+    if (shouldMakeAbstract && !psiClass.hasModifierProperty(PsiModifier.ABSTRACT) && !psiClass.isEnum) {
         val classModifiers = psiClass.modifierList!!
         if (classModifiers.hasModifierProperty(PsiModifier.FINAL)) {
             classModifiers.setModifierProperty(PsiModifier.FINAL, false)

src/main/kotlin/platform/mixin/inspection/shadow/MissingAbstractShadowsInEnumInspection.kt

@@ -0,0 +1,88 @@
+/*
+ * Minecraft Development for IntelliJ
+ *
+ * https://mcdev.io/
+ *
+ * Copyright (C) 2026 minecraft-dev
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation, version 3.0 only.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.demonwav.mcdev.platform.mixin.inspection.shadow
+
+import com.demonwav.mcdev.platform.mixin.action.insertShadows
+import com.demonwav.mcdev.platform.mixin.inspection.MixinInspection
+import com.demonwav.mcdev.platform.mixin.util.findOrConstructSourceMethod
+import com.demonwav.mcdev.platform.mixin.util.hasAccess
+import com.demonwav.mcdev.platform.mixin.util.isMixin
+import com.demonwav.mcdev.platform.mixin.util.mixinTargets
+import com.demonwav.mcdev.util.findMatchingMethod
+import com.intellij.codeInspection.LocalQuickFixOnPsiElement
+import com.intellij.codeInspection.ProblemsHolder
+import com.intellij.openapi.project.Project
+import com.intellij.psi.JavaElementVisitor
+import com.intellij.psi.PsiClass
+import com.intellij.psi.PsiElement
+import com.intellij.psi.PsiFile
+import com.intellij.psi.PsiMethod
+import org.objectweb.asm.Opcodes
+
+class MissingAbstractShadowsInEnumInspection : MixinInspection() {
+    override fun getStaticDescription() = "Reports missing abstract shadows in enum mixins"
+
+    override fun buildVisitor(holder: ProblemsHolder) = object : JavaElementVisitor() {
+        override fun visitClass(aClass: PsiClass) {
+            if (!aClass.isEnum || !aClass.isMixin) {
+                return
+            }
+
+            val missingShadows = getMissingShadows(holder.project, aClass)
+
+            if (missingShadows.isNotEmpty()) {
+                holder.registerProblem(
+                    aClass.nameIdentifier ?: aClass,
+                    "Missing abstract shadows: ${missingShadows.joinToString { it.name }}",
+                    AddMissingShadowsFix(aClass)
+                )
+            }
+        }
+    }
+
+    private class AddMissingShadowsFix(aClass: PsiClass) : LocalQuickFixOnPsiElement(aClass) {
+        override fun getFamilyName() = "Add missing shadows"
+        override fun getText() = "Add missing shadows"
+
+        override fun invoke(project: Project, psiFile: PsiFile, startElement: PsiElement, endElement: PsiElement) {
+            val aClass = startElement as? PsiClass ?: return
+            val missingShadows = getMissingShadows(project, aClass)
+            insertShadows(project, aClass, missingShadows.asSequence())
+        }
+    }
+
+    companion object {
+        private fun getMissingShadows(project: Project, aClass: PsiClass): List<PsiMethod> {
+            val requiredShadows = aClass.mixinTargets.flatMap { mixinTarget ->
+                if (!mixinTarget.hasAccess(Opcodes.ACC_ABSTRACT)) {
+                    return@flatMap emptyList()
+                }
+                mixinTarget.methods
+                    .filter { it.hasAccess(Opcodes.ACC_ABSTRACT) }
+                    .map { it.findOrConstructSourceMethod(mixinTarget, project, canDecompile = false) }
+            }
+
+            return requiredShadows.filter {
+                aClass.findMatchingMethod(it, checkBases = false) == null
+            }
+        }
+    }
+}

src/main/resources/META-INF/plugin.xml

@@ -1503,6 +1503,14 @@
                          level="ERROR"
                          hasStaticDescription="true"
                          implementationClass="com.demonwav.mcdev.platform.mixin.inspection.shadow.ShadowFinalInspection"/>
+        <localInspection displayName="Missing abstract shadows in enum mixin"
+                         shortName="MissingAbstractShadowsInEnumMixin"
+                         groupName="Mixin"
+                         language="JAVA"
+                         enabledByDefault="true"
+                         level="ERROR"
+                         hasStaticDescription="true"
+                         implementationClass="com.demonwav.mcdev.platform.mixin.inspection.shadow.MissingAbstractShadowsInEnumInspection"/>
         <!--endregion-->
 
         <!--region Mixin Extras -->