Mixin shadow target resolution extension

src/main/kotlin/platform/mixin/completion/MixinCompletionContributor.kt

@@ -21,6 +21,7 @@
 package com.demonwav.mcdev.platform.mixin.completion
 
 import com.demonwav.mcdev.platform.mixin.reference.MixinReferences
+import com.demonwav.mcdev.platform.mixin.handlers.ShadowTargetResolver
 import com.demonwav.mcdev.platform.mixin.util.findShadowTargets
 import com.demonwav.mcdev.platform.mixin.util.isMixin
 import com.demonwav.mcdev.util.constantStringValue
@@ -124,7 +125,9 @@ class MixinCompletionContributor : CompletionContributor() {
             }
 
             // Process methods and fields from target class
-            val elements = findShadowTargets(psiClass, start, superMixin != null)
+            val extensionTargets = ShadowTargetResolver.EP_NAME.extensionList.asSequence()
+                .flatMap { it.findCompletionTargets(start) }
+            val elements = (findShadowTargets(psiClass, start, superMixin != null) + extensionTargets)
                 .filter {
                     val name = it.name
                     StringUtil.isJavaIdentifier(name) && prefixMatcher.prefixMatches(name)

src/main/kotlin/platform/mixin/handlers/ShadowHandler.kt

@@ -49,7 +49,7 @@ class ShadowHandler : MixinMemberAnnotationHandler {
         if (hasAliases(annotation)) return emptyList()
         val member = annotation.parentOfType<PsiMember>() ?: return emptyList()
         val name = getEffectiveName(annotation, member) ?: return emptyList()
-        return when (member) {
+        val targetMembers = when (member) {
             is PsiMethod -> listOfNotNull(
                 targetClass.findMethod(MemberReference(name, member.descriptor))
                     ?.let { MethodTargetMember(targetClass, it) },
@@ -59,6 +59,10 @@ class ShadowHandler : MixinMemberAnnotationHandler {
             )
             else -> emptyList()
         }
+        if (targetMembers.isNotEmpty()) return targetMembers
+        return ShadowTargetResolver.EP_NAME.extensionList.flatMap {
+            it.resolveTarget(annotation, targetClass, member, name)
+        }
     }
 
     override fun isUnresolved(annotation: PsiAnnotation, targetClass: ClassNode): InsnResolutionInfo.Failure? {

src/main/kotlin/platform/mixin/handlers/ShadowTargetResolver.kt

@@ -0,0 +1,44 @@
+/*
+ * 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.handlers
+
+import com.demonwav.mcdev.platform.mixin.util.MixinTargetMember
+import com.intellij.openapi.extensions.ExtensionPointName
+import com.intellij.psi.PsiAnnotation
+import com.intellij.psi.PsiMember
+import com.intellij.psi.PsiClass
+import org.objectweb.asm.tree.ClassNode
+
+/** Supplies shadow targets contributed by other transformations of the same target class. */
+interface ShadowTargetResolver {
+    fun resolveTarget(
+        shadow: PsiAnnotation,
+        targetClass: ClassNode,
+        member: PsiMember,
+        effectiveName: String,
+    ): List<MixinTargetMember>
+
+    fun findCompletionTargets(mixinClass: PsiClass): Sequence<MixinTargetMember> = emptySequence()
+
+    companion object {
+        val EP_NAME = ExtensionPointName.create<ShadowTargetResolver>("com.demonwav.minecraft-dev.shadowTargetResolver")
+    }
+}

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

@@ -111,6 +111,8 @@
         <extensionPoint name="mixinAnnotationHandler" beanClass="com.demonwav.mcdev.platform.mixin.handlers.MixinAnnotationHandlerInfo" dynamic="true">
             <with attribute="implementation" implements="com.demonwav.mcdev.platform.mixin.handlers.MixinAnnotationHandler"/>
         </extensionPoint>
+        <extensionPoint name="shadowTargetResolver"
+                        interface="com.demonwav.mcdev.platform.mixin.handlers.ShadowTargetResolver" dynamic="true"/>
         <extensionPoint name="injectionPoint"
                         beanClass="com.demonwav.mcdev.platform.mixin.handlers.injectionPoint.InjectionPointInfo"
                         dynamic="true">