plus: do not generate ambiguos overloads.

libraries/stdlib/src/generated/_Generators.kt

@@ -635,24 +635,20 @@ public fun <T> Set<T>.plus(array: Array<out T>): Set<T> {
     return result
 }
 
-/**
- * Returns a list containing all elements of the original collection and then all elements of the given [collection].
- */
-public fun <T> Collection<T>.plus(collection: Collection<T>): List<T> {
-    val result = ArrayList<T>(this.size() + collection.size())
-    result.addAll(this)
-    result.addAll(collection)
-    return result
-}
-
 /**
  * Returns a list containing all elements of the original collection and then all elements of the given [collection].
  */
 public fun <T> Collection<T>.plus(collection: Iterable<T>): List<T> {
-    if (collection is Collection) return this.plus(collection)
-    val result = ArrayList<T>(this)
-    result.addAll(collection)
-    return result
+    if (collection is Collection) {
+        val result = ArrayList<T>(this.size() + collection.size())
+        result.addAll(this)
+        result.addAll(collection)
+        return result
+    } else {
+        val result = ArrayList<T>(this)
+        result.addAll(collection)
+        return result
+    }
 }
 
 /**

libraries/tools/kotlin-stdlib-gen/src/templates/Generators.kt

@@ -52,7 +52,7 @@ fun generators(): List<GenericFunction> {
         only(Iterables, Collections, Sets, Sequences)
         doc { "Returns a list containing all elements of the original collection and then all elements of the given [collection]." }
         returns("List<T>")
-        returns("SELF", ArraysOfObjects, ArraysOfPrimitives, Sets, Sequences)
+        returns("SELF", Sets, Sequences)
         body {
             """
             if (this is Collection) return this.plus(collection)
@@ -64,14 +64,19 @@ fun generators(): List<GenericFunction> {
         }
         body(Collections) {
             """
-            if (collection is Collection) return this.plus(collection)
-            val result = ArrayList<T>(this)
-            result.addAll(collection)
-            return result
+            if (collection is Collection) {
+                val result = ArrayList<T>(this.size() + collection.size())
+                result.addAll(this)
+                result.addAll(collection)
+                return result
+            } else {
+                val result = ArrayList<T>(this)
+                result.addAll(collection)
+                return result
+            }
             """
         }
 
-        // TODO: try to precalculate size
         // TODO: use immutable set builder when available
         doc(Sets) { "Returns a set containing all elements both of the original set and the given [collection]." }
         body(Sets) {
@@ -91,20 +96,6 @@ fun generators(): List<GenericFunction> {
         }
     }
 
-    templates add f("plus(collection: Collection<T>)") {
-        only(Collections)
-        doc { "Returns a list containing all elements of the original collection and then all elements of the given [collection]." }
-        returns("List<T>")
-        body {
-            """
-            val result = ArrayList<T>(this.size() + collection.size())
-            result.addAll(this)
-            result.addAll(collection)
-            return result
-            """
-        }
-    }
-
     templates add f("plus(array: Array<out T>)") {
         only(Iterables, Collections, Sets, Sequences)
         doc { "Returns a list containing all elements of the original collection and then all elements of the given [array]." }