diff --git a/js/js.libraries/src/core/stringsCode.kt b/js/js.libraries/src/core/stringsCode.kt
index ffaa4fb87fb..d89e6b18245 100644
--- a/js/js.libraries/src/core/stringsCode.kt
+++ b/js/js.libraries/src/core/stringsCode.kt
@@ -17,7 +17,7 @@ public inline fun String.matches(regex : String) : Boolean {
  * @includeFunctionBody ../../test/StringTest.kt capitalize
  */
 public inline fun String.capitalize(): String {
-    return if (notEmpty()) substring(0, 1).toUpperCase() + substring(1) else this
+    return if (isNotEmpty()) substring(0, 1).toUpperCase() + substring(1) else this
 }
 
 /**
@@ -26,5 +26,5 @@ public inline fun String.capitalize(): String {
  * @includeFunctionBody ../../test/StringTest.kt decapitalize
  */
 public inline fun String.decapitalize(): String {
-    return if (notEmpty()) substring(0, 1).toLowerCase() + substring(1) else this
+    return if (isNotEmpty()) substring(0, 1).toLowerCase() + substring(1) else this
 }
diff --git a/libraries/stdlib/src/kotlin/Arrays.kt b/libraries/stdlib/src/kotlin/Arrays.kt
index 177a10421d0..1ef8ea339ce 100644
--- a/libraries/stdlib/src/kotlin/Arrays.kt
+++ b/libraries/stdlib/src/kotlin/Arrays.kt
@@ -1,7 +1,7 @@
 package kotlin
 
 /** Returns true if the array is not empty */
-public inline fun <T> Array<T>.notEmpty() : Boolean = !this.isEmpty()
+public inline fun <T> Array<T>.isNotEmpty() : Boolean = !this.isEmpty()
 
 /** Returns true if the array is empty */
 public inline fun <T> Array<T>.isEmpty() : Boolean = this.size == 0
diff --git a/libraries/stdlib/src/kotlin/JUtil.kt b/libraries/stdlib/src/kotlin/JUtil.kt
index fc015040ae4..f792d402a76 100644
--- a/libraries/stdlib/src/kotlin/JUtil.kt
+++ b/libraries/stdlib/src/kotlin/JUtil.kt
@@ -17,7 +17,11 @@ val Int.indices: IntRange
     get() = 0..this-1
 
 /** Returns true if the collection is not empty */
-public inline fun <T> Collection<T>.notEmpty() : Boolean = !this.isEmpty()
+public inline fun <T> Collection<T>.isNotEmpty() : Boolean = !this.isEmpty()
+
+/** Returns true if this collection is empty */
+val Collection<*>.notEmpty : Boolean
+    get() = isNotEmpty()
 
 /** Returns the Collection if its not null otherwise it returns the empty list */
 public inline fun <T> Collection<T>?.orEmpty() : Collection<T>
diff --git a/libraries/stdlib/src/kotlin/Strings.kt b/libraries/stdlib/src/kotlin/Strings.kt
index f6250be1f5c..b2926a53549 100644
--- a/libraries/stdlib/src/kotlin/Strings.kt
+++ b/libraries/stdlib/src/kotlin/Strings.kt
@@ -30,7 +30,7 @@ public inline fun String.trimTrailing(postfix: String): String {
 }
 
 /** Returns true if the string is not null and not empty */
-public inline fun String?.notEmpty() : Boolean = this != null && this.length() > 0
+public inline fun String?.isNotEmpty() : Boolean = this != null && this.length() > 0
 
 /**
 Iterator for characters of given CharSequence
diff --git a/libraries/stdlib/src/kotlin/StringsJVM.kt b/libraries/stdlib/src/kotlin/StringsJVM.kt
index 75ec8609cce..0a314bc5b83 100644
--- a/libraries/stdlib/src/kotlin/StringsJVM.kt
+++ b/libraries/stdlib/src/kotlin/StringsJVM.kt
@@ -179,7 +179,7 @@ get() = length()
  * @includeFunctionBody ../../test/StringTest.kt capitalize
  */
 public inline fun String.capitalize(): String {
-    return if (notEmpty() && charAt(0).isLowerCase()) substring(0, 1).toUpperCase() + substring(1) else this
+    return if (isNotEmpty() && charAt(0).isLowerCase()) substring(0, 1).toUpperCase() + substring(1) else this
 }
 
 /**
@@ -188,7 +188,7 @@ public inline fun String.capitalize(): String {
  * @includeFunctionBody ../../test/StringTest.kt decapitalize
  */
 public inline fun String.decapitalize(): String {
-    return if (notEmpty() && charAt(0).isUpperCase()) substring(0, 1).toLowerCase() + substring(1) else this
+    return if (isNotEmpty() && charAt(0).isUpperCase()) substring(0, 1).toLowerCase() + substring(1) else this
 }
 
 /**
diff --git a/libraries/tools/kdoc/src/main/kotlin/org/jetbrains/kotlin/doc/model/KotlinModel.kt b/libraries/tools/kdoc/src/main/kotlin/org/jetbrains/kotlin/doc/model/KotlinModel.kt
index 299c8512e6a..e46c57dfb61 100644
--- a/libraries/tools/kdoc/src/main/kotlin/org/jetbrains/kotlin/doc/model/KotlinModel.kt
+++ b/libraries/tools/kdoc/src/main/kotlin/org/jetbrains/kotlin/doc/model/KotlinModel.kt
@@ -298,7 +298,7 @@ class KModel(val context: BindingContext, val config: KDocConfig, val sourceDirs
             val scope = descriptor.getMemberScope()
             addFunctions(pkg, scope)
             pkg.local = isLocal(descriptor)
-            pkg.useExternalLink = pkg.model.config.resolveLink(pkg.name, false).notEmpty()
+            pkg.useExternalLink = pkg.model.config.resolveLink(pkg.name, false).isNotEmpty()
 
             if (pkg.wikiDescription.isEmpty()) {
                 // lets try find a custom doc
diff --git a/libraries/tools/kdoc/src/main/kotlin/org/jetbrains/kotlin/doc/templates/KDocTemplate.kt b/libraries/tools/kdoc/src/main/kotlin/org/jetbrains/kotlin/doc/templates/KDocTemplate.kt
index 4d3c1c74cba..231e64a8fb5 100644
--- a/libraries/tools/kdoc/src/main/kotlin/org/jetbrains/kotlin/doc/templates/KDocTemplate.kt
+++ b/libraries/tools/kdoc/src/main/kotlin/org/jetbrains/kotlin/doc/templates/KDocTemplate.kt
@@ -134,7 +134,7 @@ abstract class KDocTemplate() : TextTemplate() {
         return if (c != null) {
             val prefix = if (c.isAnnotation()) "@" else ""
             val cname = c.name
-            if ((cname.startsWith("jet.Function") || cname.startsWith("jet.ExtensionFunction")) && arguments.notEmpty()) {
+            if ((cname.startsWith("jet.Function") || cname.startsWith("jet.ExtensionFunction")) && arguments.isNotEmpty()) {
                 val rt = arguments.last()
                 // TODO use drop()
                 val rest = arguments.subList(0, arguments.size - 1).orEmpty()
diff --git a/libraries/tools/kdoc/src/main/kotlin/org/jetbrains/kotlin/doc/templates/PackageFrameTemplate.kt b/libraries/tools/kdoc/src/main/kotlin/org/jetbrains/kotlin/doc/templates/PackageFrameTemplate.kt
index ad9e22a9cd2..32594db6568 100644
--- a/libraries/tools/kdoc/src/main/kotlin/org/jetbrains/kotlin/doc/templates/PackageFrameTemplate.kt
+++ b/libraries/tools/kdoc/src/main/kotlin/org/jetbrains/kotlin/doc/templates/PackageFrameTemplate.kt
@@ -103,7 +103,7 @@ ${stylesheets()}
     }
     protected fun printPackageProperties(): Unit {
         val list = pkg.packageProperties()
-        if (list.notEmpty()) {
+        if (list.isNotEmpty()) {
             println("""<TABLE BORDER="0" WIDTH="100%" SUMMARY="">
 <TR>
 <TD NOWRAP><FONT size="+1" CLASS="FrameHeadingFont">Properties</FONT>&nbsp;
diff --git a/libraries/tools/kdoc/src/main/kotlin/org/jetbrains/kotlin/doc/templates/PackageTemplateSupport.kt b/libraries/tools/kdoc/src/main/kotlin/org/jetbrains/kotlin/doc/templates/PackageTemplateSupport.kt
index 9d52609a46f..fae302fae54 100644
--- a/libraries/tools/kdoc/src/main/kotlin/org/jetbrains/kotlin/doc/templates/PackageTemplateSupport.kt
+++ b/libraries/tools/kdoc/src/main/kotlin/org/jetbrains/kotlin/doc/templates/PackageTemplateSupport.kt
@@ -17,7 +17,7 @@ abstract class PackageTemplateSupport(open val pkg: KPackage) : KDocTemplate() {
     protected fun keyword(name: String): String = "<B>$name</B>"
 
     fun printFunctionSummary(functions: Collection<KFunction>): Unit {
-        if (functions.notEmpty()) {
+        if (functions.isNotEmpty()) {
             println("""<!-- ========== FUNCTION SUMMARY =========== -->
 
 <A NAME="method_summary"><!-- --></A>
@@ -90,7 +90,7 @@ abstract class PackageTemplateSupport(open val pkg: KPackage) : KDocTemplate() {
     }
 
     fun printFunctionDetail(functions: Collection<KFunction>): Unit {
-        if (functions.notEmpty()) {
+        if (functions.isNotEmpty()) {
             println("""
 
             <!-- ============ FUNCTION DETAIL ========== -->
@@ -159,7 +159,7 @@ abstract class PackageTemplateSupport(open val pkg: KPackage) : KDocTemplate() {
     }
 
     fun printPropertySummary(properties: Collection<KProperty>): Unit {
-        if (properties.notEmpty()) {
+        if (properties.isNotEmpty()) {
             println("""<!-- ========== PROPERTY SUMMARY =========== -->
 
 <A NAME="method_summary"><!-- --></A>
diff --git a/libraries/tools/kotlin-stdlib-gen/src/generators/GenerateJavaScriptStubs.kt b/libraries/tools/kotlin-stdlib-gen/src/generators/GenerateJavaScriptStubs.kt
index e5e7da9056e..37d80b189cb 100644
--- a/libraries/tools/kotlin-stdlib-gen/src/generators/GenerateJavaScriptStubs.kt
+++ b/libraries/tools/kotlin-stdlib-gen/src/generators/GenerateJavaScriptStubs.kt
@@ -150,7 +150,7 @@ import js.noImpl
             }
             val fields = klass.getDeclaredFields()
             if (fields != null) {
-                if (fields.notEmpty()) {
+                if (fields.isNotEmpty()) {
                     println("")
                     println("    public class object {")
                     for (field in fields) {