to avoid running resolve under ClsTypeElement lock, return empty modifier list if we're currently calculating the return type (the modifier list is requested to apply type annotations, and we don't care about them anyway)

#KT-12966 Fixed

compiler/light-classes/src/org/jetbrains/kotlin/asJava/elements/KtLightMethod.kt

@@ -21,6 +21,7 @@ import com.intellij.openapi.util.TextRange
 import com.intellij.psi.*
 import com.intellij.psi.impl.compiled.ClsTypeElementImpl
 import com.intellij.psi.impl.light.LightMethod
+import com.intellij.psi.impl.light.LightModifierList
 import com.intellij.psi.scope.PsiScopeProcessor
 import com.intellij.psi.util.*
 import com.intellij.util.IncorrectOperationException
@@ -33,6 +34,7 @@ import org.jetbrains.kotlin.asJava.unwrapped
 import org.jetbrains.kotlin.idea.KotlinLanguage
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.resolve.DescriptorUtils
+import org.jetbrains.kotlin.resolve.jvm.KotlinJavaPsiFacade
 import org.jetbrains.kotlin.resolve.jvm.diagnostics.JvmDeclarationOriginKind
 
 interface KtLightMethod : PsiMethod, KtLightDeclaration<KtDeclaration, PsiMethod> {
@@ -53,6 +55,8 @@ sealed class KtLightMethodImpl(
         delegateTypeElement?.let { ClsTypeElementImpl(this, it.canonicalText, /*ClsTypeElementImpl.VARIANCE_NONE */ 0.toChar()) }
     }
 
+    private val calculatingReturnType = ThreadLocal<Boolean>()
+
     override fun getContainingClass(): KtLightClass = super.getContainingClass() as KtLightClass
 
     private val paramsList: CachedValue<PsiParameterList> by lazy(LazyThreadSafetyMode.PUBLICATION) {
@@ -141,7 +145,12 @@ sealed class KtLightMethodImpl(
         else clsDelegate.modifierList
     }
 
-    override fun getModifierList() = _modifierList
+    override fun getModifierList(): PsiModifierList {
+        if (calculatingReturnType.get() == true) {
+            return KotlinJavaPsiFacade.getInstance(project).emptyModifierList
+        }
+        return _modifierList
+    }
 
     override fun getNameIdentifier() = lightIdentifier
 
@@ -206,7 +215,15 @@ sealed class KtLightMethodImpl(
     // which is relied upon by java type inference
     override fun getReturnTypeElement(): PsiTypeElement? = returnTypeElem
 
-    override fun getReturnType() = returnTypeElement?.type
+    override fun getReturnType(): PsiType? {
+        calculatingReturnType.set(true)
+        try {
+            return returnTypeElement?.type
+        }
+        finally {
+            calculatingReturnType.set(false)
+        }
+    }
 
     companion object Factory {
         fun create(