From 11fed1674e49683fa856fc8cf26d1f2199f12b21 Mon Sep 17 00:00:00 2001
From: Denis Zharkov <denis.zharkov@jetbrains.com>
Date: Tue, 1 Sep 2015 13:44:02 +0300
Subject: [PATCH] Deprecate `extension` annotation in favor of `Extension`

---
 compiler/testData/builtin-classes.txt                  |  8 ++++----
 compiler/testData/codegen/box/regressions/kt3999.kt    |  6 +++---
 .../diagnostics/tests/FreeFunctionCalledAsExtension.kt |  6 +++---
 .../tests/FreeFunctionCalledAsExtension.txt            |  2 +-
 .../tests/annotations/extensionFunctionType.kt         |  4 ++--
 .../tests/annotations/extensionFunctionType.txt        |  4 ++--
 .../tests/inline/binaryExpressions/arrayAccess.kt      |  2 +-
 .../tests/inline/binaryExpressions/assignment.kt       |  6 +++---
 .../tests/inline/binaryExpressions/comparison.kt       |  2 +-
 .../tests/inline/binaryExpressions/componentAccess.kt  |  4 ++--
 .../tests/inline/binaryExpressions/contains.kt         |  2 +-
 .../tests/inline/binaryExpressions/mathOperations.kt   |  6 +++---
 .../tests/inline/binaryExpressions/rangeTo.kt          |  2 +-
 .../tests/inline/unaryExpressions/mathOperation.kt     |  8 ++++----
 .../tests/inline/unaryExpressions/notOperation.kt      |  2 +-
 compiler/testData/renderer/FunctionTypes.kt            |  6 +++---
 .../functionTypes/invokeForExtensionFunctionType.txt   |  2 +-
 .../functionTypes/valOfExtensionFunctionTypeInvoke.txt |  2 +-
 core/builtins/src/kotlin/Annotations.kt                |  2 +-
 .../org/jetbrains/kotlin/builtins/KotlinBuiltIns.java  |  4 ++--
 .../ExcludedClass/ExcludedClass.dependency.kt          |  4 ++--
 .../basic/multifile/ExcludedClass/ExcludedClass.kt     |  4 ++--
 .../multifile/ExcludedJavaClass/ExcludedJavaClass.kt   |  4 ++--
 .../ExcludedJavaClass/somePackage/ExctraClass.java     |  6 ++++++
 .../ExcludedJavaClass/somePackage/ExtraClass.java      |  5 -----
 .../NotImportedExtensionFunction2.dependency.kt        |  2 +-
 .../NotImportedExtensionFunction3.dependency.kt        |  4 ++--
 .../decompiledText/FunctionTypes/FunctionTypes.kt      |  4 ++--
 idea/testData/decompiler/stubBuilder/Types/Types.kt    |  4 ++--
 idea/testData/unifier/equivalence/types/function0.kt   |  2 +-
 idea/testData/unifier/equivalence/types/function1.kt   |  4 ++--
 .../unifier/equivalence/types/function1.kt.match       |  2 +-
 idea/testData/unifier/equivalence/types/function2.kt   |  4 ++--
 .../unifier/equivalence/types/function2.kt.match       |  2 +-
 .../testData/expression/invoke/cases/infixCall.kt      | 10 +++++-----
 spec-docs/function-types.md                            |  2 +-
 36 files changed, 72 insertions(+), 71 deletions(-)
 create mode 100644 idea/idea-completion/testData/basic/multifile/ExcludedJavaClass/somePackage/ExctraClass.java
 delete mode 100644 idea/idea-completion/testData/basic/multifile/ExcludedJavaClass/somePackage/ExtraClass.java

diff --git a/compiler/testData/builtin-classes.txt b/compiler/testData/builtin-classes.txt
index 1e7adabe012..ae5fe57c4ee 100644
--- a/compiler/testData/builtin-classes.txt
+++ b/compiler/testData/builtin-classes.txt
@@ -427,6 +427,10 @@ public abstract class Enum</*0*/ E : kotlin.Enum<E>> : kotlin.Comparable<E> {
     }
 }
 
+kotlin.annotation.target(allowedTargets = {AnnotationTarget.TYPE}) kotlin.annotation.annotation(mustBeDocumented = true) public final class Extension : kotlin.Annotation {
+    /*primary*/ public constructor Extension()
+}
+
 public final class Float : kotlin.Number, kotlin.Comparable<kotlin.Float> {
     /*primary*/ private constructor Float()
     public final fun compareTo(/*0*/ other: kotlin.Byte): kotlin.Int
@@ -1262,10 +1266,6 @@ kotlin.annotation.target(allowedTargets = {AnnotationTarget.CLASSIFIER, Annotati
         internal final fun <get-value>(): kotlin.String
 }
 
-kotlin.annotation.target(allowedTargets = {AnnotationTarget.TYPE}) kotlin.annotation.annotation(mustBeDocumented = true) public final class extension : kotlin.Annotation {
-    /*primary*/ public constructor extension()
-}
-
 kotlin.annotation.target(allowedTargets = {AnnotationTarget.FUNCTION, AnnotationTarget.PROPERTY}) kotlin.annotation.annotation(mustBeDocumented = true, retention = AnnotationRetention.RUNTIME) public final class inline : kotlin.Annotation {
     /*primary*/ public constructor inline(/*0*/ strategy: kotlin.InlineStrategy = ...)
     public final val strategy: kotlin.InlineStrategy
diff --git a/compiler/testData/codegen/box/regressions/kt3999.kt b/compiler/testData/codegen/box/regressions/kt3999.kt
index 4eac6a2e580..2bbe3215dc3 100644
--- a/compiler/testData/codegen/box/regressions/kt3999.kt
+++ b/compiler/testData/codegen/box/regressions/kt3999.kt
@@ -11,9 +11,9 @@ fun test1() {
 }
 
 fun test2() {
-  val a: (@extension Function2<*, *, *>).(@extension Function2<*, *, *>)->Unit = {}
-  val b: (@extension Function2<*, *, *>).(@extension Function2<*, *, *>)->Unit = {"$this $it"}
-  val c: (@extension Function2<*, *, *>).(@extension Function2<*, *, *>)->Unit = {}
+  val a: (@Extension Function2<*, *, *>).(@Extension Function2<*, *, *>)->Unit = {}
+  val b: (@Extension Function2<*, *, *>).(@Extension Function2<*, *, *>)->Unit = {"$this $it"}
+  val c: (@Extension Function2<*, *, *>).(@Extension Function2<*, *, *>)->Unit = {}
   a.b(c)
   a b c
 }
diff --git a/compiler/testData/diagnostics/tests/FreeFunctionCalledAsExtension.kt b/compiler/testData/diagnostics/tests/FreeFunctionCalledAsExtension.kt
index 0b552e64264..e890300076d 100644
--- a/compiler/testData/diagnostics/tests/FreeFunctionCalledAsExtension.kt
+++ b/compiler/testData/diagnostics/tests/FreeFunctionCalledAsExtension.kt
@@ -6,8 +6,8 @@ fun foo(a: (String) -> Unit) {
 
 interface A : (String) -> Unit {}
 
-fun foo(a: @extension A) {
-    // @extension annotation on an unrelated type shouldn't have any effect on this diagnostic.
-    // Only kotlin.Function{n} type annotated with @extension should
+fun foo(a: @Extension A) {
+    // @Extension annotation on an unrelated type shouldn't have any effect on this diagnostic.
+    // Only kotlin.Function{n} type annotated with @Extension should
     "".<!FREE_FUNCTION_CALLED_AS_EXTENSION!>a<!>()
 }
diff --git a/compiler/testData/diagnostics/tests/FreeFunctionCalledAsExtension.txt b/compiler/testData/diagnostics/tests/FreeFunctionCalledAsExtension.txt
index f6d7797c85a..030563a258c 100644
--- a/compiler/testData/diagnostics/tests/FreeFunctionCalledAsExtension.txt
+++ b/compiler/testData/diagnostics/tests/FreeFunctionCalledAsExtension.txt
@@ -1,7 +1,7 @@
 package
 
 internal fun foo(/*0*/ a: (kotlin.String) -> kotlin.Unit): kotlin.Unit
-internal fun foo(/*0*/ a: @[kotlin.extension()] A): kotlin.Unit
+internal fun foo(/*0*/ a: @[kotlin.Extension()] A): kotlin.Unit
 
 internal interface A : (kotlin.String) -> kotlin.Unit {
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
diff --git a/compiler/testData/diagnostics/tests/annotations/extensionFunctionType.kt b/compiler/testData/diagnostics/tests/annotations/extensionFunctionType.kt
index 61ab3238531..3d0e6230392 100644
--- a/compiler/testData/diagnostics/tests/annotations/extensionFunctionType.kt
+++ b/compiler/testData/diagnostics/tests/annotations/extensionFunctionType.kt
@@ -4,7 +4,7 @@ annotation class ann
 
 interface Some {
     fun f1(): String.() -> Int
-    fun f2(): @extension String.() -> Int
+    fun f2(): @Extension String.() -> Int
     fun f3(): @ann String.() -> Int
-    fun f4(): @extension @ann String.() -> Int
+    fun f4(): @Extension @ann String.() -> Int
 }
diff --git a/compiler/testData/diagnostics/tests/annotations/extensionFunctionType.txt b/compiler/testData/diagnostics/tests/annotations/extensionFunctionType.txt
index d7f1091fb38..07c41792011 100644
--- a/compiler/testData/diagnostics/tests/annotations/extensionFunctionType.txt
+++ b/compiler/testData/diagnostics/tests/annotations/extensionFunctionType.txt
@@ -3,9 +3,9 @@ package
 internal interface Some {
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     internal abstract fun f1(): kotlin.String.() -> kotlin.Int
-    internal abstract fun f2(): @[kotlin.extension()] kotlin.String.() -> kotlin.Int
+    internal abstract fun f2(): @[kotlin.Extension()] kotlin.String.() -> kotlin.Int
     internal abstract fun f3(): @[ann()] kotlin.String.() -> kotlin.Int
-    internal abstract fun f4(): @[kotlin.extension() ann()] kotlin.String.() -> kotlin.Int
+    internal abstract fun f4(): @[kotlin.Extension() ann()] kotlin.String.() -> kotlin.Int
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
diff --git a/compiler/testData/diagnostics/tests/inline/binaryExpressions/arrayAccess.kt b/compiler/testData/diagnostics/tests/inline/binaryExpressions/arrayAccess.kt
index 9af1f669a65..d73c6b4cc6b 100644
--- a/compiler/testData/diagnostics/tests/inline/binaryExpressions/arrayAccess.kt
+++ b/compiler/testData/diagnostics/tests/inline/binaryExpressions/arrayAccess.kt
@@ -12,7 +12,7 @@ fun <T, U, V> Function2<T, U, V>.get(index : Int) {
 
 }
 
-fun <T, U, V, W> @extension Function3<T, U, V, W>.get(index : Int) {
+fun <T, U, V, W> @Extension Function3<T, U, V, W>.get(index : Int) {
 
 }
 
diff --git a/compiler/testData/diagnostics/tests/inline/binaryExpressions/assignment.kt b/compiler/testData/diagnostics/tests/inline/binaryExpressions/assignment.kt
index b3b183e71c0..9827bd367d2 100644
--- a/compiler/testData/diagnostics/tests/inline/binaryExpressions/assignment.kt
+++ b/compiler/testData/diagnostics/tests/inline/binaryExpressions/assignment.kt
@@ -12,14 +12,14 @@ inline fun <T, U> Function1<T, U>.plusAssign(p: Function1<T, U>) {
     <!USAGE_IS_NOT_INLINABLE!>p<!> -= <!USAGE_IS_NOT_INLINABLE!>this<!>
 }
 
-fun <T, U, V> @extension Function2<T, U, V>.minusAssign(ext : @extension Function2<T, U, V>) {}
+fun <T, U, V> @Extension Function2<T, U, V>.minusAssign(ext : @Extension Function2<T, U, V>) {}
 
-inline fun <T, U, V> @extension Function2<T, U, V>.modAssign(ext : @extension Function2<T, U, V>) = {
+inline fun <T, U, V> @Extension Function2<T, U, V>.modAssign(ext : @Extension Function2<T, U, V>) = {
     this += ext
     ext += this
 }
 
-inline fun <T, U, V> @extension Function2<T, U, V>.plusAssign(ext : @extension Function2<T, U, V>) {
+inline fun <T, U, V> @Extension Function2<T, U, V>.plusAssign(ext : @Extension Function2<T, U, V>) {
     <!USAGE_IS_NOT_INLINABLE!>this<!> -= <!USAGE_IS_NOT_INLINABLE!>ext<!>
     <!USAGE_IS_NOT_INLINABLE!>ext<!> -= <!USAGE_IS_NOT_INLINABLE!>this<!>
 }
diff --git a/compiler/testData/diagnostics/tests/inline/binaryExpressions/comparison.kt b/compiler/testData/diagnostics/tests/inline/binaryExpressions/comparison.kt
index c5832c2e0bf..2d8ed2997bc 100644
--- a/compiler/testData/diagnostics/tests/inline/binaryExpressions/comparison.kt
+++ b/compiler/testData/diagnostics/tests/inline/binaryExpressions/comparison.kt
@@ -11,7 +11,7 @@ inline fun <T, U, V> inlineFunWithInvoke(s: (p: T) -> U) {
 
 //noinline
 fun <T, U, V> Function2<T, U, V>.compareTo(index : Function2<T, U, V>) = 1
-fun <T, U, V, W> @extension Function3<T, U, V, W>.compareTo(index : @extension Function3<T, U, V, W>) = 1
+fun <T, U, V, W> @Extension Function3<T, U, V, W>.compareTo(index : @Extension Function3<T, U, V, W>) = 1
 
 inline fun <T, U, V, W> inlineFunWithInvoke(s: (p: T, l: U) -> V, ext: T.(p: U, l: V) -> W) {
     <!USAGE_IS_NOT_INLINABLE!>s<!> < <!USAGE_IS_NOT_INLINABLE!>s<!>
diff --git a/compiler/testData/diagnostics/tests/inline/binaryExpressions/componentAccess.kt b/compiler/testData/diagnostics/tests/inline/binaryExpressions/componentAccess.kt
index fd317924dbc..bfbd3ac3462 100644
--- a/compiler/testData/diagnostics/tests/inline/binaryExpressions/componentAccess.kt
+++ b/compiler/testData/diagnostics/tests/inline/binaryExpressions/componentAccess.kt
@@ -9,8 +9,8 @@ inline fun <T, U, V> inlineFunWithInvoke(s: (p: T) -> U) {
 fun <T, U, V> Function2<T, U, V>.component1() = 1
 fun <T, U, V> Function2<T, U, V>.component2() = 2
 
-fun <T, U, V, W> @extension Function3<T, U, V, W>.component1() = 1
-fun <T, U, V, W> @extension Function3<T, U, V, W>.component2() = 2
+fun <T, U, V, W> @Extension Function3<T, U, V, W>.component1() = 1
+fun <T, U, V, W> @Extension Function3<T, U, V, W>.component2() = 2
 
 inline fun <T, U, V, W> inlineFunWithInvoke(s: (p: T, l: U) -> V, ext: T.(p: U, l: V) -> W) {
     val (d1, e1) = <!USAGE_IS_NOT_INLINABLE, USAGE_IS_NOT_INLINABLE!>s<!>
diff --git a/compiler/testData/diagnostics/tests/inline/binaryExpressions/contains.kt b/compiler/testData/diagnostics/tests/inline/binaryExpressions/contains.kt
index 5bc22123a4f..149b9b99159 100644
--- a/compiler/testData/diagnostics/tests/inline/binaryExpressions/contains.kt
+++ b/compiler/testData/diagnostics/tests/inline/binaryExpressions/contains.kt
@@ -13,7 +13,7 @@ inline fun <T, U, V> inlineFunWithInvoke(s: (p: T) -> U) {
 
 fun <T, U, V> Function2<T, U, V>.contains(p: Function2<T, U, V>): Boolean = false
 
-fun <T, U, V, W> @extension Function3<T, U, V, W>.contains(ext: @extension Function3<T, U, V, W>): Boolean = false
+fun <T, U, V, W> @Extension Function3<T, U, V, W>.contains(ext: @Extension Function3<T, U, V, W>): Boolean = false
 
 inline fun <T, U, V> inlineFunWithInvoke(s: (p: T, l: U) -> U, ext: T.(p: U, l: U) -> V) {
     <!USAGE_IS_NOT_INLINABLE!>s<!> in <!USAGE_IS_NOT_INLINABLE!>s<!>
diff --git a/compiler/testData/diagnostics/tests/inline/binaryExpressions/mathOperations.kt b/compiler/testData/diagnostics/tests/inline/binaryExpressions/mathOperations.kt
index 729bf0f42c1..f6134fd3064 100644
--- a/compiler/testData/diagnostics/tests/inline/binaryExpressions/mathOperations.kt
+++ b/compiler/testData/diagnostics/tests/inline/binaryExpressions/mathOperations.kt
@@ -3,7 +3,7 @@ fun <T, U> Function1<T, U>.minus(p: Function1<T, U>) {
 
 }
 
-fun <T, U, V> @extension Function2<T, U, V>.minus(p: T.(p: U) -> V) {
+fun <T, U, V> @Extension Function2<T, U, V>.minus(p: T.(p: U) -> V) {
 
 }
 
@@ -11,7 +11,7 @@ inline fun <T, U> Function1<T, U>.plus(p: Function1<T, U>) {
     <!USAGE_IS_NOT_INLINABLE!>this<!> - <!USAGE_IS_NOT_INLINABLE!>p<!>
 }
 
-inline fun <T, U, V> @extension Function2<T, U, V>.plus(p: T.(p: U) -> V) {
+inline fun <T, U, V> @Extension Function2<T, U, V>.plus(p: T.(p: U) -> V) {
     <!USAGE_IS_NOT_INLINABLE!>this<!> - <!USAGE_IS_NOT_INLINABLE!>p<!>
 }
 
@@ -29,6 +29,6 @@ inline fun <T, U> Function1<T, U>.submit() {
     this + this
 }
 
-inline fun <T, U, V> @extension Function2<T, U, V>.submit() {
+inline fun <T, U, V> @Extension Function2<T, U, V>.submit() {
     this + this
 }
diff --git a/compiler/testData/diagnostics/tests/inline/binaryExpressions/rangeTo.kt b/compiler/testData/diagnostics/tests/inline/binaryExpressions/rangeTo.kt
index 2a73c7a00db..ed297511152 100644
--- a/compiler/testData/diagnostics/tests/inline/binaryExpressions/rangeTo.kt
+++ b/compiler/testData/diagnostics/tests/inline/binaryExpressions/rangeTo.kt
@@ -16,7 +16,7 @@ fun <T, U, V> Function2<T, U, V>.rangeTo(p: Function2<T, U, V>): Range<Int> {
     return 1..2
 }
 
-fun <T, U, V, W> @extension Function3<T, U, V, W>.rangeTo(ext: @extension Function3<T, U, V, W>): Range<Int> {
+fun <T, U, V, W> @Extension Function3<T, U, V, W>.rangeTo(ext: @Extension Function3<T, U, V, W>): Range<Int> {
     return 1..2
 }
 
diff --git a/compiler/testData/diagnostics/tests/inline/unaryExpressions/mathOperation.kt b/compiler/testData/diagnostics/tests/inline/unaryExpressions/mathOperation.kt
index ddf78874b40..5a8ec85c859 100644
--- a/compiler/testData/diagnostics/tests/inline/unaryExpressions/mathOperation.kt
+++ b/compiler/testData/diagnostics/tests/inline/unaryExpressions/mathOperation.kt
@@ -5,10 +5,10 @@ fun <T, V> Function1<T, V>.minus() = this
 inline fun <T, V> Function1<T, V>.inc() = <!USAGE_IS_NOT_INLINABLE!>this<!>
 fun <T, V> Function1<T, V>.dec() = this
 
-inline fun <T, V> @extension Function2<T, T, V>.plus(){}
-fun <T, V> @extension Function2<T, T, V>.minus(){}
-inline fun <T, V> @extension Function2<T, T, V>.inc() = <!USAGE_IS_NOT_INLINABLE!>this<!>
-fun <T, V> @extension Function2<T, T, V>.dec() = this
+inline fun <T, V> @Extension Function2<T, T, V>.plus(){}
+fun <T, V> @Extension Function2<T, T, V>.minus(){}
+inline fun <T, V> @Extension Function2<T, T, V>.inc() = <!USAGE_IS_NOT_INLINABLE!>this<!>
+fun <T, V> @Extension Function2<T, T, V>.dec() = this
 
 inline fun <T, V> inlineFunWithInvoke(s: (p: T) -> V, ext: T.(p: T) -> V) {
     +s
diff --git a/compiler/testData/diagnostics/tests/inline/unaryExpressions/notOperation.kt b/compiler/testData/diagnostics/tests/inline/unaryExpressions/notOperation.kt
index 805562fd1da..777a2acfe9c 100644
--- a/compiler/testData/diagnostics/tests/inline/unaryExpressions/notOperation.kt
+++ b/compiler/testData/diagnostics/tests/inline/unaryExpressions/notOperation.kt
@@ -11,7 +11,7 @@ fun <T, U, V> Function2<T, U, V>.not() : Boolean {
     return !this
 }
 
-fun <T, U, V, W> @extension Function3<T, U, V, W>.not() : Boolean {
+fun <T, U, V, W> @Extension Function3<T, U, V, W>.not() : Boolean {
     return !this
 }
 
diff --git a/compiler/testData/renderer/FunctionTypes.kt b/compiler/testData/renderer/FunctionTypes.kt
index 250d5ddb7de..7573a97fe72 100644
--- a/compiler/testData/renderer/FunctionTypes.kt
+++ b/compiler/testData/renderer/FunctionTypes.kt
@@ -5,18 +5,18 @@ var v4: Function1<Int, String>
 var v4: (() -> Int, (String) -> Unit) -> String
 var v5: Int.() -> Int
 var v6 : Int.(String, Int) -> Unit
-var v7 : @extension Function2<Int, String, Boolean>
+var v7 : @Extension Function2<Int, String, Boolean>
 
 class F: Function0<Unit>
 var v8: F
 
-class EF: @extension Function1<String, Unit>
+class EF: @Extension Function1<String, Unit>
 var v9: EF
 
 class GF<T>: Function0<T>
 var v10: GF<Any>
 
-class GEF<A, B>: @extension Function1<A, B>
+class GEF<A, B>: @Extension Function1<A, B>
 var v11: GEF<Any, Any>
 
 var v12: (() -> Unit).() -> Unit
diff --git a/compiler/testData/resolvedCalls/functionTypes/invokeForExtensionFunctionType.txt b/compiler/testData/resolvedCalls/functionTypes/invokeForExtensionFunctionType.txt
index 0c8e537cbaa..ec09b6b99ce 100644
--- a/compiler/testData/resolvedCalls/functionTypes/invokeForExtensionFunctionType.txt
+++ b/compiler/testData/resolvedCalls/functionTypes/invokeForExtensionFunctionType.txt
@@ -8,5 +8,5 @@ Resolved call:
 Resulting descriptor: fun Int.invoke(): Unit defined in kotlin.Function1
 
 Explicit receiver kind = BOTH_RECEIVERS
-Dispatch receiver = f {[kotlin.extension] Function1<Int, Unit>}
+Dispatch receiver = f {[kotlin.Extension] Function1<Int, Unit>}
 Extension receiver = 1 {Int}
diff --git a/compiler/testData/resolvedCalls/functionTypes/valOfExtensionFunctionTypeInvoke.txt b/compiler/testData/resolvedCalls/functionTypes/valOfExtensionFunctionTypeInvoke.txt
index 251275e2c66..81a4dc7cdfd 100644
--- a/compiler/testData/resolvedCalls/functionTypes/valOfExtensionFunctionTypeInvoke.txt
+++ b/compiler/testData/resolvedCalls/functionTypes/valOfExtensionFunctionTypeInvoke.txt
@@ -12,5 +12,5 @@ Resolved call:
 Resulting descriptor: fun Int.invoke(): Unit defined in kotlin.Function1
 
 Explicit receiver kind = BOTH_RECEIVERS
-Dispatch receiver = foo {[kotlin.extension] Function1<Int, Unit>}
+Dispatch receiver = foo {[kotlin.Extension] Function1<Int, Unit>}
 Extension receiver = 1 {Int}
diff --git a/core/builtins/src/kotlin/Annotations.kt b/core/builtins/src/kotlin/Annotations.kt
index ab30d0de2eb..ded577bb484 100644
--- a/core/builtins/src/kotlin/Annotations.kt
+++ b/core/builtins/src/kotlin/Annotations.kt
@@ -59,7 +59,7 @@ public annotation(retention = BINARY, mustBeDocumented = true) class ReplaceWith
  * Signifies that the annotated functional type represents an extension function.
  */
 target(TYPE)
-public annotation(mustBeDocumented = true) class extension
+public annotation(mustBeDocumented = true) class Extension
 
 /**
  * Suppresses the given compilation warnings in the annotated element.
diff --git a/core/descriptors/src/org/jetbrains/kotlin/builtins/KotlinBuiltIns.java b/core/descriptors/src/org/jetbrains/kotlin/builtins/KotlinBuiltIns.java
index 725c8101a5b..644edffacd0 100644
--- a/core/descriptors/src/org/jetbrains/kotlin/builtins/KotlinBuiltIns.java
+++ b/core/descriptors/src/org/jetbrains/kotlin/builtins/KotlinBuiltIns.java
@@ -175,7 +175,7 @@ public class KotlinBuiltIns {
         public final FqName inline = fqName("inline");
         public final FqName noinline = fqName("noinline");
         public final FqName inlineOptions = fqName("inlineOptions");
-        public final FqName extension = fqName("extension");
+        public final FqName extension = fqName("Extension");
         public final FqName target = annotationName("target");
         public final FqName annotation = annotationName("annotation");
         public final FqName annotationTarget = annotationName("AnnotationTarget");
@@ -721,7 +721,7 @@ public class KotlinBuiltIns {
 
     @NotNull
     public AnnotationDescriptor createExtensionAnnotation() {
-        return new AnnotationDescriptorImpl(getBuiltInClassByName("extension").getDefaultType(),
+        return new AnnotationDescriptorImpl(getBuiltInClassByName(FQ_NAMES.extension.shortName()).getDefaultType(),
                                             Collections.<ValueParameterDescriptor, ConstantValue<?>>emptyMap(), SourceElement.NO_SOURCE);
     }
 
diff --git a/idea/idea-completion/testData/basic/multifile/ExcludedClass/ExcludedClass.dependency.kt b/idea/idea-completion/testData/basic/multifile/ExcludedClass/ExcludedClass.dependency.kt
index 4983cec7adf..48876406d8c 100644
--- a/idea/idea-completion/testData/basic/multifile/ExcludedClass/ExcludedClass.dependency.kt
+++ b/idea/idea-completion/testData/basic/multifile/ExcludedClass/ExcludedClass.dependency.kt
@@ -1,5 +1,5 @@
 package somePackage
 
 class ExcludedClass
-
-class ExtraClass
\ No newline at end of file
+// Such strange name here needed to make completion prefix not intersecting with kotlin.Extension
+class ExctraClass
\ No newline at end of file
diff --git a/idea/idea-completion/testData/basic/multifile/ExcludedClass/ExcludedClass.kt b/idea/idea-completion/testData/basic/multifile/ExcludedClass/ExcludedClass.kt
index f342359fe2d..eda6b2ae679 100644
--- a/idea/idea-completion/testData/basic/multifile/ExcludedClass/ExcludedClass.kt
+++ b/idea/idea-completion/testData/basic/multifile/ExcludedClass/ExcludedClass.kt
@@ -1,4 +1,4 @@
-val x = Ex<caret>
+val x = Exc<caret>
 
 // ABSENT: ExcludedClass
-// EXIST: ExtraClass
\ No newline at end of file
+// EXIST: ExctraClass
\ No newline at end of file
diff --git a/idea/idea-completion/testData/basic/multifile/ExcludedJavaClass/ExcludedJavaClass.kt b/idea/idea-completion/testData/basic/multifile/ExcludedJavaClass/ExcludedJavaClass.kt
index f342359fe2d..eda6b2ae679 100644
--- a/idea/idea-completion/testData/basic/multifile/ExcludedJavaClass/ExcludedJavaClass.kt
+++ b/idea/idea-completion/testData/basic/multifile/ExcludedJavaClass/ExcludedJavaClass.kt
@@ -1,4 +1,4 @@
-val x = Ex<caret>
+val x = Exc<caret>
 
 // ABSENT: ExcludedClass
-// EXIST: ExtraClass
\ No newline at end of file
+// EXIST: ExctraClass
\ No newline at end of file
diff --git a/idea/idea-completion/testData/basic/multifile/ExcludedJavaClass/somePackage/ExctraClass.java b/idea/idea-completion/testData/basic/multifile/ExcludedJavaClass/somePackage/ExctraClass.java
new file mode 100644
index 00000000000..b1cda98a37b
--- /dev/null
+++ b/idea/idea-completion/testData/basic/multifile/ExcludedJavaClass/somePackage/ExctraClass.java
@@ -0,0 +1,6 @@
+package somePackage;
+
+// Such strange name here needed to make completion prefix not intersecting with kotlin.Extension
+public class ExctraClass {
+
+}
\ No newline at end of file
diff --git a/idea/idea-completion/testData/basic/multifile/ExcludedJavaClass/somePackage/ExtraClass.java b/idea/idea-completion/testData/basic/multifile/ExcludedJavaClass/somePackage/ExtraClass.java
deleted file mode 100644
index 8e27c9baf5d..00000000000
--- a/idea/idea-completion/testData/basic/multifile/ExcludedJavaClass/somePackage/ExtraClass.java
+++ /dev/null
@@ -1,5 +0,0 @@
-package somePackage;
-
-public class ExtraClass {
-
-}
\ No newline at end of file
diff --git a/idea/idea-completion/testData/basic/multifile/NotImportedExtensionFunction2/NotImportedExtensionFunction2.dependency.kt b/idea/idea-completion/testData/basic/multifile/NotImportedExtensionFunction2/NotImportedExtensionFunction2.dependency.kt
index a6cb72ea336..e7a45fcbefd 100644
--- a/idea/idea-completion/testData/basic/multifile/NotImportedExtensionFunction2/NotImportedExtensionFunction2.dependency.kt
+++ b/idea/idea-completion/testData/basic/multifile/NotImportedExtensionFunction2/NotImportedExtensionFunction2.dependency.kt
@@ -6,7 +6,7 @@ fun (() -> Unit)?.helloFun1() {
 fun Function0<Unit>.helloFun2() {
 }
 
-fun @extension Function1<String, Unit>.helloFun3() {
+fun @Extension Function1<String, Unit>.helloFun3() {
 }
 
 fun Function1<String, Unit>.helloFun4() {
diff --git a/idea/idea-completion/testData/basic/multifile/NotImportedExtensionFunction3/NotImportedExtensionFunction3.dependency.kt b/idea/idea-completion/testData/basic/multifile/NotImportedExtensionFunction3/NotImportedExtensionFunction3.dependency.kt
index 450acef59e4..c418879227e 100644
--- a/idea/idea-completion/testData/basic/multifile/NotImportedExtensionFunction3/NotImportedExtensionFunction3.dependency.kt
+++ b/idea/idea-completion/testData/basic/multifile/NotImportedExtensionFunction3/NotImportedExtensionFunction3.dependency.kt
@@ -6,10 +6,10 @@ fun (String.() -> Unit)?.helloFun1() {
 fun Function0<Unit>.helloFun2() {
 }
 
-fun @extension Function1<String, Unit>.helloFun3() {
+fun @Extension Function1<String, Unit>.helloFun3() {
 }
 
-fun @extension Function1<Int, Unit>.helloFun4() {
+fun @Extension Function1<Int, Unit>.helloFun4() {
 }
 
 fun Function1<String, Unit>.helloFun5() {
diff --git a/idea/testData/decompiler/decompiledText/FunctionTypes/FunctionTypes.kt b/idea/testData/decompiler/decompiledText/FunctionTypes/FunctionTypes.kt
index 8bb9dc0b7a1..dbc4041dd83 100644
--- a/idea/testData/decompiler/decompiledText/FunctionTypes/FunctionTypes.kt
+++ b/idea/testData/decompiler/decompiledText/FunctionTypes/FunctionTypes.kt
@@ -21,9 +21,9 @@ class FunctionTypes {
     public fun f2(f: Function2<Int, *, String>) {
     }
 
-    public fun f3(f: @extension Function2<Int, Int, Unit>) {
+    public fun f3(f: @Extension Function2<Int, Int, Unit>) {
     }
 
-    public fun f4(f: List<@extension Function1<*, *>>) {
+    public fun f4(f: List<@Extension Function1<*, *>>) {
     }
 }
diff --git a/idea/testData/decompiler/stubBuilder/Types/Types.kt b/idea/testData/decompiler/stubBuilder/Types/Types.kt
index ace2bbb3e8c..4b92c32a0b5 100644
--- a/idea/testData/decompiler/stubBuilder/Types/Types.kt
+++ b/idea/testData/decompiler/stubBuilder/Types/Types.kt
@@ -19,7 +19,7 @@ abstract class Types {
 
     abstract val starList: List<*>
     abstract val starFun: Function1<*, *>
-    abstract val extFun: @extension Function2<Int, Int, Unit>
-    abstract val listExtStarFun: List<@extension Function1<*, *>>
+    abstract val extFun: @Extension Function2<Int, Int, Unit>
+    abstract val listExtStarFun: List<@Extension Function1<*, *>>
     abstract val funTypeWithStarAndNonStar: Function1<*, Int>
 }
\ No newline at end of file
diff --git a/idea/testData/unifier/equivalence/types/function0.kt b/idea/testData/unifier/equivalence/types/function0.kt
index adc2e0288c7..039b31f2fff 100644
--- a/idea/testData/unifier/equivalence/types/function0.kt
+++ b/idea/testData/unifier/equivalence/types/function0.kt
@@ -4,4 +4,4 @@ val c: <selection>() -> String</selection> = { "" }
 val d: () -> kotlin.String = { "" }
 val e: () -> Unit = {  }
 val f: Any.() -> String = { "" }
-val g: @extension Function1<String, String> = { "" }
+val g: @Extension Function1<String, String> = { "" }
diff --git a/idea/testData/unifier/equivalence/types/function1.kt b/idea/testData/unifier/equivalence/types/function1.kt
index eb07cab248c..f62fb7dc609 100644
--- a/idea/testData/unifier/equivalence/types/function1.kt
+++ b/idea/testData/unifier/equivalence/types/function1.kt
@@ -5,6 +5,6 @@ val d: (n: Int) -> kotlin.String = { "" }
 val e: (String) -> Int = { 0 }
 val f: () -> Int = { 0 }
 val g: Int.() -> String = { "" }
-val h: @extension Function2<Int, Int, String> = { "" }
+val h: @Extension Function2<Int, Int, String> = { "" }
 val i: (m: Int) -> kotlin.String = { "" }
-val j: @extension Function1<Int, String> = { "" }
+val j: @Extension Function1<Int, String> = { "" }
diff --git a/idea/testData/unifier/equivalence/types/function1.kt.match b/idea/testData/unifier/equivalence/types/function1.kt.match
index 50dc32be4c4..9c50410998c 100644
--- a/idea/testData/unifier/equivalence/types/function1.kt.match
+++ b/idea/testData/unifier/equivalence/types/function1.kt.match
@@ -10,4 +10,4 @@ Int.() -> String
 
 (m: Int) -> kotlin.String
 
-@extension Function1<Int, String>
+@Extension Function1<Int, String>
diff --git a/idea/testData/unifier/equivalence/types/function2.kt b/idea/testData/unifier/equivalence/types/function2.kt
index 7e98a01c251..31f21c5aecb 100644
--- a/idea/testData/unifier/equivalence/types/function2.kt
+++ b/idea/testData/unifier/equivalence/types/function2.kt
@@ -6,6 +6,6 @@ val e: (String) -> Int = { 0 }
 val f: () -> Int = { 0 }
 val g: Any.(Int) -> String = { "" }
 val h: Int.(Any) -> String = { "" }
-val i: @extension Function3<Any, Any, Int, String> = { a, b -> "" }
+val i: @Extension Function3<Any, Any, Int, String> = { a, b -> "" }
 val j: (t: Any, u: Int) -> kotlin.String = { a, b ->  "" }
-val k: @extension Function2<Any, Int, String> = { "" }
+val k: @Extension Function2<Any, Int, String> = { "" }
diff --git a/idea/testData/unifier/equivalence/types/function2.kt.match b/idea/testData/unifier/equivalence/types/function2.kt.match
index f3d72847299..2fa4558f6dd 100644
--- a/idea/testData/unifier/equivalence/types/function2.kt.match
+++ b/idea/testData/unifier/equivalence/types/function2.kt.match
@@ -10,4 +10,4 @@ Any.(Int) -> String
 
 (t: Any, u: Int) -> kotlin.String
 
-@extension Function2<Any, Int, String>
+@Extension Function2<Any, Int, String>
diff --git a/js/js.translator/testData/expression/invoke/cases/infixCall.kt b/js/js.translator/testData/expression/invoke/cases/infixCall.kt
index b83f9225ff8..5fa7f872f69 100644
--- a/js/js.translator/testData/expression/invoke/cases/infixCall.kt
+++ b/js/js.translator/testData/expression/invoke/cases/infixCall.kt
@@ -15,13 +15,13 @@ fun test1(): String {
 }
 
 fun test2(): String {
-    val a: (@extension Function2<*, *, *>).(@extension Function2<*, *, *>)->String = { "a" }
-    val b: (@extension Function2<*, *, *>).(@extension Function2<*, *, *>)->String = {
-        val aa = this as @extension Function2<Any?, Any?, Any?>;
-        val cc = it as @extension Function2<Any?, Any?, Any?>;
+    val a: (@Extension Function2<*, *, *>).(@Extension Function2<*, *, *>)->String = { "a" }
+    val b: (@Extension Function2<*, *, *>).(@Extension Function2<*, *, *>)->String = {
+        val aa = this as @Extension Function2<Any?, Any?, Any?>;
+        val cc = it as @Extension Function2<Any?, Any?, Any?>;
         "${null.aa(null)} b ${null.cc(null)}"
     }
-    val c: (@extension Function2<*, *, *>).(@extension Function2<*, *, *>)->String = { "c" }
+    val c: (@Extension Function2<*, *, *>).(@Extension Function2<*, *, *>)->String = { "c" }
 
     val f = a.b(c) // works
     val s = a b c  //compiler crashes
diff --git a/spec-docs/function-types.md b/spec-docs/function-types.md
index 46818584d95..7a3e11a822b 100644
--- a/spec-docs/function-types.md
+++ b/spec-docs/function-types.md
@@ -40,7 +40,7 @@ or an extension function expression where a function is expected and vice versa.
 If you really want to do that, change the shape, assign literal to a variable or use the `as` operator.
 
 So basically you can now safely coerce values between function and extension function types,
-but still should invoke them in the format which you specified in their type (with or without `@extension`).
+but still should invoke them in the format which you specified in their type (with or without `@Extension`).
 
 With this we'll get rid of classes `ExtensionFunction0`, `ExtensionFunction1`, ...
 and the rest of this article will deal only with usual functions.