Make KotlinType.isError extension instead of member

plugins/kapt3/src/org/jetbrains/kotlin/kapt3/stubs/errorTypeConversion.kt

@@ -29,6 +29,7 @@ import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.types.KotlinType
 import org.jetbrains.kotlin.types.Variance
+import org.jetbrains.kotlin.types.isError
 
 internal fun convertKtType(
         reference: KtTypeReference?,
@@ -149,4 +150,4 @@ fun KotlinType.containsErrorTypes(allowedDepth: Int = 10): Boolean {
     if (this.isError) return true
     if (this.arguments.any { !it.isStarProjection && it.type.containsErrorTypes(allowedDepth - 1) }) return true
     return false
-}
+}