Get rid of redundant intrinsic

Also drop 'safe' parameter from TypeIntrinsics.checkcast,
because it's supposed to work as JVM checkcast (i.e. accepting nulls)

.idea/dictionaries/dzharkov.xml

@@ -1,6 +1,7 @@
 <component name="ProjectDictionaryState">
   <dictionary name="dzharkov">
     <words>
+      <w>checkcast</w>
       <w>insn</w>
     </words>
   </dictionary>

compiler/backend/src/org/jetbrains/kotlin/codegen/intrinsics/TypeIntrinsics.kt

@@ -78,26 +78,28 @@ public object TypeIntrinsics {
         instanceofInsn.desc = asmType.internalName
     }
 
-    public @JvmStatic fun checkcast(v: InstructionAdapter, jetType: KotlinType, asmType: Type, safe: Boolean) {
+    @JvmStatic
+    public fun checkcast(
+            v: InstructionAdapter,
+            kotlinType: KotlinType, asmType: Type,
+            // This parameter is just for sake of optimization:
+            // when we generate 'as?' we do necessary intrinsic checks
+            // when calling TypeIntrinsics.instanceOf, so here we can just make checkcast
+            safe: Boolean) {
         if (safe) {
             v.checkcast(asmType)
             return
         }
 
-        val functionTypeArity = getFunctionTypeArity(jetType)
+        val functionTypeArity = getFunctionTypeArity(kotlinType)
         if (functionTypeArity >= 0) {
             v.iconst(functionTypeArity)
-            if (safe) {
+            v.typeIntrinsic(BEFORE_CHECKCAST_TO_FUNCTION_OF_ARITY, BEFORE_CHECKCAST_TO_FUNCTION_OF_ARITY_DESCRIPTOR)
-                v.typeIntrinsic(BEFORE_SAFE_CHECKCAST_TO_FUNCTION_OF_ARITY, BEFORE_SAFE_CHECKCAST_TO_FUNCTION_OF_ARITY_DESCRIPTOR)
-            }
-            else {
-                v.typeIntrinsic(BEFORE_CHECKCAST_TO_FUNCTION_OF_ARITY, BEFORE_CHECKCAST_TO_FUNCTION_OF_ARITY_DESCRIPTOR)
-            }
             v.checkcast(asmType)
             return
         }
 
-        val asMutableCollectionMethodName = getAsMutableCollectionMethodName(jetType)
+        val asMutableCollectionMethodName = getAsMutableCollectionMethodName(kotlinType)
         if (asMutableCollectionMethodName != null) {
             v.typeIntrinsic(asMutableCollectionMethodName, getAsMutableCollectionDescriptor(asmType))
             return
@@ -106,20 +108,22 @@ public object TypeIntrinsics {
         v.checkcast(asmType)
     }
 
-    public @JvmStatic fun checkcast(checkcastInsn: TypeInsnNode, instructions: InsnList, jetType: KotlinType, asmType: Type, safe: Boolean) {
+    @JvmStatic
+    public fun checkcast(
+            checkcastInsn: TypeInsnNode,
+            instructions: InsnList,
+            kotlinType: KotlinType, asmType: Type,
+            safe: Boolean) {
         if (safe) {
             checkcastInsn.desc = asmType.internalName
             return
         }
 
-        val functionTypeArity = getFunctionTypeArity(jetType)
+        val functionTypeArity = getFunctionTypeArity(kotlinType)
         if (functionTypeArity >= 0) {
             instructions.insertBefore(checkcastInsn, iconstNode(functionTypeArity))
 
-            val beforeCheckcast = if (safe)
+            val beforeCheckcast = typeIntrinsicNode(BEFORE_CHECKCAST_TO_FUNCTION_OF_ARITY, BEFORE_CHECKCAST_TO_FUNCTION_OF_ARITY_DESCRIPTOR)
-                typeIntrinsicNode(BEFORE_SAFE_CHECKCAST_TO_FUNCTION_OF_ARITY, BEFORE_SAFE_CHECKCAST_TO_FUNCTION_OF_ARITY_DESCRIPTOR)
-            else
-                typeIntrinsicNode(BEFORE_CHECKCAST_TO_FUNCTION_OF_ARITY, BEFORE_CHECKCAST_TO_FUNCTION_OF_ARITY_DESCRIPTOR)
             instructions.insertBefore(checkcastInsn, beforeCheckcast)
 
             instructions.insertBefore(checkcastInsn, TypeInsnNode(Opcodes.CHECKCAST, asmType.internalName))
@@ -127,7 +131,7 @@ public object TypeIntrinsics {
             return
         }
 
-        val asMutableCollectionMethodName = getAsMutableCollectionMethodName(jetType)
+        val asMutableCollectionMethodName = getAsMutableCollectionMethodName(kotlinType)
         if (asMutableCollectionMethodName != null) {
             instructions.insertBefore(checkcastInsn,
                                       typeIntrinsicNode(asMutableCollectionMethodName, getAsMutableCollectionDescriptor(asmType)))
@@ -211,9 +215,4 @@ public object TypeIntrinsics {
 
     private val BEFORE_CHECKCAST_TO_FUNCTION_OF_ARITY_DESCRIPTOR =
             Type.getMethodDescriptor(OBJECT_TYPE, OBJECT_TYPE, Type.INT_TYPE)
-
-    private val BEFORE_SAFE_CHECKCAST_TO_FUNCTION_OF_ARITY = "beforeSafeCheckcastToFunctionOfArity"
-
-    private val BEFORE_SAFE_CHECKCAST_TO_FUNCTION_OF_ARITY_DESCRIPTOR =
-            Type.getMethodDescriptor(OBJECT_TYPE, OBJECT_TYPE, Type.INT_TYPE)
 }

core/runtime.jvm/src/kotlin/jvm/internal/TypeIntrinsics.java

@@ -361,12 +361,4 @@ public class TypeIntrinsics {
         }
         return obj;
     }
-
-    public static Object beforeSafeCheckcastToFunctionOfArity(Object obj, int arity) {
-        // TODO should we instead inline bytecode for this in TypeIntrinsics.kt?
-        if (obj == null || !isFunctionOfArity(obj, arity)) {
-            return null;
-        }
-        return obj;
-    }
 }