diff --git a/compiler/fir/analysis-tests/testData/resolve/inference/unitUpperBound.fir.txt b/compiler/fir/analysis-tests/testData/resolve/inference/unitUpperBound.fir.txt
index a9ad8499b28..2306ee28e69 100644
--- a/compiler/fir/analysis-tests/testData/resolve/inference/unitUpperBound.fir.txt
+++ b/compiler/fir/analysis-tests/testData/resolve/inference/unitUpperBound.fir.txt
@@ -6,7 +6,7 @@ FILE: unitUpperBound.kt
 
         public final fun foo(x: R|kotlin/collections/List<kotlin/String>|): R|kotlin/Unit| {
             lvar w: R|kotlin/Int| = Int(1)
-            R|<local>/x|.R|kotlin/collections/ifEmpty|<R|kotlin/collections/List<kotlin/String>|, R|kotlin/Any|>(<L> = ifEmpty@fun <anonymous>(): R|kotlin/Any| <inline=Inline, kind=UNKNOWN>  {
+            R|<local>/x|.R|kotlin/collections/ifEmpty|<R|kotlin/collections/List<kotlin/String>|, R|kotlin/Any|>(<L> = ifEmpty@fun <anonymous>(): R|kotlin/Any| <inline=Inline, kind=AT_MOST_ONCE>  {
                 R|<local>/w| = R|<local>/w|.R|kotlin/Int.plus|(Int(2))
             }
             )
diff --git a/libraries/stdlib/common/src/generated/_Arrays.kt b/libraries/stdlib/common/src/generated/_Arrays.kt
index c511a4a79c3..73883d72d3e 100644
--- a/libraries/stdlib/common/src/generated/_Arrays.kt
+++ b/libraries/stdlib/common/src/generated/_Arrays.kt
@@ -13,6 +13,7 @@ package kotlin.collections
 // See: https://github.com/JetBrains/kotlin/tree/master/libraries/stdlib
 //
 
+import kotlin.contracts.*
 import kotlin.random.*
 import kotlin.ranges.contains
 import kotlin.ranges.reversed
@@ -649,6 +650,9 @@ public expect fun CharArray.elementAt(index: Int): Char
  */
 @kotlin.internal.InlineOnly
 public inline fun <T> Array<out T>.elementAtOrElse(index: Int, defaultValue: (Int) -> T): T {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -659,6 +663,9 @@ public inline fun <T> Array<out T>.elementAtOrElse(index: Int, defaultValue: (In
  */
 @kotlin.internal.InlineOnly
 public inline fun ByteArray.elementAtOrElse(index: Int, defaultValue: (Int) -> Byte): Byte {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -669,6 +676,9 @@ public inline fun ByteArray.elementAtOrElse(index: Int, defaultValue: (Int) -> B
  */
 @kotlin.internal.InlineOnly
 public inline fun ShortArray.elementAtOrElse(index: Int, defaultValue: (Int) -> Short): Short {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -679,6 +689,9 @@ public inline fun ShortArray.elementAtOrElse(index: Int, defaultValue: (Int) ->
  */
 @kotlin.internal.InlineOnly
 public inline fun IntArray.elementAtOrElse(index: Int, defaultValue: (Int) -> Int): Int {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -689,6 +702,9 @@ public inline fun IntArray.elementAtOrElse(index: Int, defaultValue: (Int) -> In
  */
 @kotlin.internal.InlineOnly
 public inline fun LongArray.elementAtOrElse(index: Int, defaultValue: (Int) -> Long): Long {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -699,6 +715,9 @@ public inline fun LongArray.elementAtOrElse(index: Int, defaultValue: (Int) -> L
  */
 @kotlin.internal.InlineOnly
 public inline fun FloatArray.elementAtOrElse(index: Int, defaultValue: (Int) -> Float): Float {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -709,6 +728,9 @@ public inline fun FloatArray.elementAtOrElse(index: Int, defaultValue: (Int) ->
  */
 @kotlin.internal.InlineOnly
 public inline fun DoubleArray.elementAtOrElse(index: Int, defaultValue: (Int) -> Double): Double {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -719,6 +741,9 @@ public inline fun DoubleArray.elementAtOrElse(index: Int, defaultValue: (Int) ->
  */
 @kotlin.internal.InlineOnly
 public inline fun BooleanArray.elementAtOrElse(index: Int, defaultValue: (Int) -> Boolean): Boolean {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -729,6 +754,9 @@ public inline fun BooleanArray.elementAtOrElse(index: Int, defaultValue: (Int) -
  */
 @kotlin.internal.InlineOnly
 public inline fun CharArray.elementAtOrElse(index: Int, defaultValue: (Int) -> Char): Char {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -1352,6 +1380,9 @@ public inline fun CharArray.firstOrNull(predicate: (Char) -> Boolean): Char? {
  */
 @kotlin.internal.InlineOnly
 public inline fun <T> Array<out T>.getOrElse(index: Int, defaultValue: (Int) -> T): T {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -1360,6 +1391,9 @@ public inline fun <T> Array<out T>.getOrElse(index: Int, defaultValue: (Int) ->
  */
 @kotlin.internal.InlineOnly
 public inline fun ByteArray.getOrElse(index: Int, defaultValue: (Int) -> Byte): Byte {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -1368,6 +1402,9 @@ public inline fun ByteArray.getOrElse(index: Int, defaultValue: (Int) -> Byte):
  */
 @kotlin.internal.InlineOnly
 public inline fun ShortArray.getOrElse(index: Int, defaultValue: (Int) -> Short): Short {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -1376,6 +1413,9 @@ public inline fun ShortArray.getOrElse(index: Int, defaultValue: (Int) -> Short)
  */
 @kotlin.internal.InlineOnly
 public inline fun IntArray.getOrElse(index: Int, defaultValue: (Int) -> Int): Int {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -1384,6 +1424,9 @@ public inline fun IntArray.getOrElse(index: Int, defaultValue: (Int) -> Int): In
  */
 @kotlin.internal.InlineOnly
 public inline fun LongArray.getOrElse(index: Int, defaultValue: (Int) -> Long): Long {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -1392,6 +1435,9 @@ public inline fun LongArray.getOrElse(index: Int, defaultValue: (Int) -> Long):
  */
 @kotlin.internal.InlineOnly
 public inline fun FloatArray.getOrElse(index: Int, defaultValue: (Int) -> Float): Float {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -1400,6 +1446,9 @@ public inline fun FloatArray.getOrElse(index: Int, defaultValue: (Int) -> Float)
  */
 @kotlin.internal.InlineOnly
 public inline fun DoubleArray.getOrElse(index: Int, defaultValue: (Int) -> Double): Double {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -1408,6 +1457,9 @@ public inline fun DoubleArray.getOrElse(index: Int, defaultValue: (Int) -> Doubl
  */
 @kotlin.internal.InlineOnly
 public inline fun BooleanArray.getOrElse(index: Int, defaultValue: (Int) -> Boolean): Boolean {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -1416,6 +1468,9 @@ public inline fun BooleanArray.getOrElse(index: Int, defaultValue: (Int) -> Bool
  */
 @kotlin.internal.InlineOnly
 public inline fun CharArray.getOrElse(index: Int, defaultValue: (Int) -> Char): Char {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
diff --git a/libraries/stdlib/common/src/generated/_Collections.kt b/libraries/stdlib/common/src/generated/_Collections.kt
index 5b0a9d4c862..2d06d3401ac 100644
--- a/libraries/stdlib/common/src/generated/_Collections.kt
+++ b/libraries/stdlib/common/src/generated/_Collections.kt
@@ -13,6 +13,7 @@ package kotlin.collections
 // See: https://github.com/JetBrains/kotlin/tree/master/libraries/stdlib
 //
 
+import kotlin.contracts.*
 import kotlin.random.*
 import kotlin.ranges.contains
 import kotlin.ranges.reversed
@@ -103,6 +104,9 @@ public inline fun <T> List<T>.elementAt(index: Int): T {
  * @sample samples.collections.Collections.Elements.elementAtOrElse
  */
 public fun <T> Iterable<T>.elementAtOrElse(index: Int, defaultValue: (Int) -> T): T {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     if (this is List)
         return this.getOrElse(index, defaultValue)
     if (index < 0)
@@ -124,6 +128,9 @@ public fun <T> Iterable<T>.elementAtOrElse(index: Int, defaultValue: (Int) -> T)
  */
 @kotlin.internal.InlineOnly
 public inline fun <T> List<T>.elementAtOrElse(index: Int, defaultValue: (Int) -> T): T {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -294,6 +301,9 @@ public inline fun <T> Iterable<T>.firstOrNull(predicate: (T) -> Boolean): T? {
  */
 @kotlin.internal.InlineOnly
 public inline fun <T> List<T>.getOrElse(index: Int, defaultValue: (Int) -> T): T {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
diff --git a/libraries/stdlib/common/src/generated/_Comparisons.kt b/libraries/stdlib/common/src/generated/_Comparisons.kt
index ad7591920a5..3a4786cf392 100644
--- a/libraries/stdlib/common/src/generated/_Comparisons.kt
+++ b/libraries/stdlib/common/src/generated/_Comparisons.kt
@@ -13,6 +13,7 @@ package kotlin.comparisons
 // See: https://github.com/JetBrains/kotlin/tree/master/libraries/stdlib
 //
 
+import kotlin.contracts.*
 import kotlin.random.*
 
 /**
diff --git a/libraries/stdlib/common/src/generated/_Maps.kt b/libraries/stdlib/common/src/generated/_Maps.kt
index 7f2dbf6dacd..99b8141bed5 100644
--- a/libraries/stdlib/common/src/generated/_Maps.kt
+++ b/libraries/stdlib/common/src/generated/_Maps.kt
@@ -13,6 +13,7 @@ package kotlin.collections
 // See: https://github.com/JetBrains/kotlin/tree/master/libraries/stdlib
 //
 
+import kotlin.contracts.*
 import kotlin.random.*
 import kotlin.ranges.contains
 import kotlin.ranges.reversed
diff --git a/libraries/stdlib/common/src/generated/_Ranges.kt b/libraries/stdlib/common/src/generated/_Ranges.kt
index d9ba54e25e7..39a1e358515 100644
--- a/libraries/stdlib/common/src/generated/_Ranges.kt
+++ b/libraries/stdlib/common/src/generated/_Ranges.kt
@@ -13,6 +13,7 @@ package kotlin.ranges
 // See: https://github.com/JetBrains/kotlin/tree/master/libraries/stdlib
 //
 
+import kotlin.contracts.*
 import kotlin.random.*
 
 /**
diff --git a/libraries/stdlib/common/src/generated/_Sequences.kt b/libraries/stdlib/common/src/generated/_Sequences.kt
index 80fffc1675a..8ef0ec96714 100644
--- a/libraries/stdlib/common/src/generated/_Sequences.kt
+++ b/libraries/stdlib/common/src/generated/_Sequences.kt
@@ -13,6 +13,7 @@ package kotlin.sequences
 // See: https://github.com/JetBrains/kotlin/tree/master/libraries/stdlib
 //
 
+import kotlin.contracts.*
 import kotlin.random.*
 
 /**
@@ -43,6 +44,9 @@ public fun <T> Sequence<T>.elementAt(index: Int): T {
  * @sample samples.collections.Collections.Elements.elementAtOrElse
  */
 public fun <T> Sequence<T>.elementAtOrElse(index: Int, defaultValue: (Int) -> T): T {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     if (index < 0)
         return defaultValue(index)
     val iterator = iterator()
diff --git a/libraries/stdlib/common/src/generated/_Sets.kt b/libraries/stdlib/common/src/generated/_Sets.kt
index 711e541648e..3dbbd8b8daa 100644
--- a/libraries/stdlib/common/src/generated/_Sets.kt
+++ b/libraries/stdlib/common/src/generated/_Sets.kt
@@ -13,6 +13,7 @@ package kotlin.collections
 // See: https://github.com/JetBrains/kotlin/tree/master/libraries/stdlib
 //
 
+import kotlin.contracts.*
 import kotlin.random.*
 import kotlin.ranges.contains
 import kotlin.ranges.reversed
diff --git a/libraries/stdlib/common/src/generated/_Strings.kt b/libraries/stdlib/common/src/generated/_Strings.kt
index bfbde442f55..18314e30f56 100644
--- a/libraries/stdlib/common/src/generated/_Strings.kt
+++ b/libraries/stdlib/common/src/generated/_Strings.kt
@@ -13,6 +13,7 @@ package kotlin.text
 // See: https://github.com/JetBrains/kotlin/tree/master/libraries/stdlib
 //
 
+import kotlin.contracts.*
 import kotlin.random.*
 
 /**
@@ -29,6 +30,9 @@ public expect fun CharSequence.elementAt(index: Int): Char
  */
 @kotlin.internal.InlineOnly
 public inline fun CharSequence.elementAtOrElse(index: Int, defaultValue: (Int) -> Char): Char {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -132,6 +136,9 @@ public inline fun CharSequence.firstOrNull(predicate: (Char) -> Boolean): Char?
  */
 @kotlin.internal.InlineOnly
 public inline fun CharSequence.getOrElse(index: Int, defaultValue: (Int) -> Char): Char {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
diff --git a/libraries/stdlib/common/src/generated/_UArrays.kt b/libraries/stdlib/common/src/generated/_UArrays.kt
index 3a927923402..6ceb03956a5 100644
--- a/libraries/stdlib/common/src/generated/_UArrays.kt
+++ b/libraries/stdlib/common/src/generated/_UArrays.kt
@@ -14,6 +14,7 @@ package kotlin.collections
 // See: https://github.com/JetBrains/kotlin/tree/master/libraries/stdlib
 //
 
+import kotlin.contracts.*
 import kotlin.random.*
 import kotlin.ranges.contains
 import kotlin.ranges.reversed
@@ -323,6 +324,9 @@ public expect fun UShortArray.elementAt(index: Int): UShort
 @ExperimentalUnsignedTypes
 @kotlin.internal.InlineOnly
 public inline fun UIntArray.elementAtOrElse(index: Int, defaultValue: (Int) -> UInt): UInt {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -335,6 +339,9 @@ public inline fun UIntArray.elementAtOrElse(index: Int, defaultValue: (Int) -> U
 @ExperimentalUnsignedTypes
 @kotlin.internal.InlineOnly
 public inline fun ULongArray.elementAtOrElse(index: Int, defaultValue: (Int) -> ULong): ULong {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -347,6 +354,9 @@ public inline fun ULongArray.elementAtOrElse(index: Int, defaultValue: (Int) ->
 @ExperimentalUnsignedTypes
 @kotlin.internal.InlineOnly
 public inline fun UByteArray.elementAtOrElse(index: Int, defaultValue: (Int) -> UByte): UByte {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -359,6 +369,9 @@ public inline fun UByteArray.elementAtOrElse(index: Int, defaultValue: (Int) ->
 @ExperimentalUnsignedTypes
 @kotlin.internal.InlineOnly
 public inline fun UShortArray.elementAtOrElse(index: Int, defaultValue: (Int) -> UShort): UShort {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -689,6 +702,9 @@ public inline fun UShortArray.firstOrNull(predicate: (UShort) -> Boolean): UShor
 @ExperimentalUnsignedTypes
 @kotlin.internal.InlineOnly
 public inline fun UIntArray.getOrElse(index: Int, defaultValue: (Int) -> UInt): UInt {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -699,6 +715,9 @@ public inline fun UIntArray.getOrElse(index: Int, defaultValue: (Int) -> UInt):
 @ExperimentalUnsignedTypes
 @kotlin.internal.InlineOnly
 public inline fun ULongArray.getOrElse(index: Int, defaultValue: (Int) -> ULong): ULong {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -709,6 +728,9 @@ public inline fun ULongArray.getOrElse(index: Int, defaultValue: (Int) -> ULong)
 @ExperimentalUnsignedTypes
 @kotlin.internal.InlineOnly
 public inline fun UByteArray.getOrElse(index: Int, defaultValue: (Int) -> UByte): UByte {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
@@ -719,6 +741,9 @@ public inline fun UByteArray.getOrElse(index: Int, defaultValue: (Int) -> UByte)
 @ExperimentalUnsignedTypes
 @kotlin.internal.InlineOnly
 public inline fun UShortArray.getOrElse(index: Int, defaultValue: (Int) -> UShort): UShort {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
     return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
 }
 
diff --git a/libraries/stdlib/common/src/generated/_UCollections.kt b/libraries/stdlib/common/src/generated/_UCollections.kt
index 8942688491d..e2b1155f1b6 100644
--- a/libraries/stdlib/common/src/generated/_UCollections.kt
+++ b/libraries/stdlib/common/src/generated/_UCollections.kt
@@ -13,6 +13,7 @@ package kotlin.collections
 // See: https://github.com/JetBrains/kotlin/tree/master/libraries/stdlib
 //
 
+import kotlin.contracts.*
 import kotlin.random.*
 import kotlin.ranges.contains
 import kotlin.ranges.reversed
diff --git a/libraries/stdlib/common/src/generated/_UComparisons.kt b/libraries/stdlib/common/src/generated/_UComparisons.kt
index 6b109853d75..7484cd6ae75 100644
--- a/libraries/stdlib/common/src/generated/_UComparisons.kt
+++ b/libraries/stdlib/common/src/generated/_UComparisons.kt
@@ -13,6 +13,7 @@ package kotlin.comparisons
 // See: https://github.com/JetBrains/kotlin/tree/master/libraries/stdlib
 //
 
+import kotlin.contracts.*
 import kotlin.random.*
 
 /**
diff --git a/libraries/stdlib/common/src/generated/_URanges.kt b/libraries/stdlib/common/src/generated/_URanges.kt
index 7927285a591..10cfd11266d 100644
--- a/libraries/stdlib/common/src/generated/_URanges.kt
+++ b/libraries/stdlib/common/src/generated/_URanges.kt
@@ -13,6 +13,7 @@ package kotlin.ranges
 // See: https://github.com/JetBrains/kotlin/tree/master/libraries/stdlib
 //
 
+import kotlin.contracts.*
 import kotlin.random.*
 
 /**
diff --git a/libraries/stdlib/common/src/generated/_USequences.kt b/libraries/stdlib/common/src/generated/_USequences.kt
index 95a0cb25c8e..b80d3c7bdcd 100644
--- a/libraries/stdlib/common/src/generated/_USequences.kt
+++ b/libraries/stdlib/common/src/generated/_USequences.kt
@@ -13,6 +13,7 @@ package kotlin.sequences
 // See: https://github.com/JetBrains/kotlin/tree/master/libraries/stdlib
 //
 
+import kotlin.contracts.*
 import kotlin.random.*
 
 /**
diff --git a/libraries/stdlib/jdk8/src/kotlin/jvm/optionals/Optionals.kt b/libraries/stdlib/jdk8/src/kotlin/jvm/optionals/Optionals.kt
index 3065cbd214e..0a1d228259f 100644
--- a/libraries/stdlib/jdk8/src/kotlin/jvm/optionals/Optionals.kt
+++ b/libraries/stdlib/jdk8/src/kotlin/jvm/optionals/Optionals.kt
@@ -6,6 +6,7 @@
 package kotlin.jvm.optionals
 
 import java.util.Optional
+import kotlin.contracts.*
 
 /**
  * Returns this [Optional]'s value if [present][Optional.isPresent], or otherwise `null`.
@@ -26,8 +27,12 @@ public fun <T> Optional<out T & Any>.getOrDefault(defaultValue: T): T = if (isPr
  */
 @SinceKotlin("1.8")
 @WasExperimental(ExperimentalStdlibApi::class)
-public inline fun <T> Optional<out T & Any>.getOrElse(defaultValue: () -> T): T =
-    if (isPresent) get() else defaultValue()
+public inline fun <T> Optional<out T & Any>.getOrElse(defaultValue: () -> T): T {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
+    return if (isPresent) get() else defaultValue()
+}
 
 /**
  * Appends this [Optional]'s value to the given [destination] collection if [present][Optional.isPresent].
diff --git a/libraries/stdlib/src/kotlin/collections/Arrays.kt b/libraries/stdlib/src/kotlin/collections/Arrays.kt
index 9a1f0e1eac6..f789c74b42b 100644
--- a/libraries/stdlib/src/kotlin/collections/Arrays.kt
+++ b/libraries/stdlib/src/kotlin/collections/Arrays.kt
@@ -63,8 +63,12 @@ public inline fun Array<*>?.isNullOrEmpty(): Boolean {
 @SinceKotlin("1.3")
 @kotlin.internal.InlineOnly
 @Suppress("UPPER_BOUND_CANNOT_BE_ARRAY")
-public inline fun <C, R> C.ifEmpty(defaultValue: () -> R): R where C : Array<*>, C : R =
-    if (isEmpty()) defaultValue() else this
+public inline fun <C, R> C.ifEmpty(defaultValue: () -> R): R where C : Array<*>, C : R {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
+    return if (isEmpty()) defaultValue() else this
+}
 
 
 @OptIn(ExperimentalUnsignedTypes::class)
diff --git a/libraries/stdlib/src/kotlin/collections/Collections.kt b/libraries/stdlib/src/kotlin/collections/Collections.kt
index 86997d36813..23ac3061636 100644
--- a/libraries/stdlib/src/kotlin/collections/Collections.kt
+++ b/libraries/stdlib/src/kotlin/collections/Collections.kt
@@ -278,8 +278,12 @@ public inline fun <T> List<T>?.orEmpty(): List<T> = this ?: emptyList()
  */
 @SinceKotlin("1.3")
 @kotlin.internal.InlineOnly
-public inline fun <C, R> C.ifEmpty(defaultValue: () -> R): R where C : Collection<*>, C : R =
-    if (isEmpty()) defaultValue() else this
+public inline fun <C, R> C.ifEmpty(defaultValue: () -> R): R where C : Collection<*>, C : R {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
+    return if (isEmpty()) defaultValue() else this
+}
 
 
 /**
diff --git a/libraries/stdlib/src/kotlin/collections/Maps.kt b/libraries/stdlib/src/kotlin/collections/Maps.kt
index 721b4045dbf..83fbc13552c 100644
--- a/libraries/stdlib/src/kotlin/collections/Maps.kt
+++ b/libraries/stdlib/src/kotlin/collections/Maps.kt
@@ -235,8 +235,12 @@ public inline fun <K, V> Map<K, V>?.orEmpty(): Map<K, V> = this ?: emptyMap()
  */
 @SinceKotlin("1.3")
 @kotlin.internal.InlineOnly
-public inline fun <M, R> M.ifEmpty(defaultValue: () -> R): R where M : Map<*, *>, M : R =
-    if (isEmpty()) defaultValue() else this
+public inline fun <M, R> M.ifEmpty(defaultValue: () -> R): R where M : Map<*, *>, M : R {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
+    return if (isEmpty()) defaultValue() else this
+}
 
 /**
  * Checks if the map contains the given key.
@@ -334,7 +338,12 @@ public inline fun <K, V> Map.Entry<K, V>.toPair(): Pair<K, V> = Pair(key, value)
  * @sample samples.collections.Maps.Usage.getOrElse
  */
 @kotlin.internal.InlineOnly
-public inline fun <K, V> Map<K, V>.getOrElse(key: K, defaultValue: () -> V): V = get(key) ?: defaultValue()
+public inline fun <K, V> Map<K, V>.getOrElse(key: K, defaultValue: () -> V): V {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
+    return get(key) ?: defaultValue()
+}
 
 
 internal inline fun <K, V> Map<K, V>.getOrElseNullable(key: K, defaultValue: () -> V): V {
diff --git a/libraries/stdlib/src/kotlin/text/Strings.kt b/libraries/stdlib/src/kotlin/text/Strings.kt
index 11c5f2c50ea..87cc1bf3188 100644
--- a/libraries/stdlib/src/kotlin/text/Strings.kt
+++ b/libraries/stdlib/src/kotlin/text/Strings.kt
@@ -8,6 +8,7 @@
 
 package kotlin.text
 
+import kotlin.contracts.InvocationKind
 import kotlin.contracts.contract
 import kotlin.jvm.JvmName
 
@@ -355,8 +356,12 @@ public inline fun String?.orEmpty(): String = this ?: ""
  */
 @SinceKotlin("1.3")
 @kotlin.internal.InlineOnly
-public inline fun <C, R> C.ifEmpty(defaultValue: () -> R): R where C : CharSequence, C : R =
-    if (isEmpty()) defaultValue() else this
+public inline fun <C, R> C.ifEmpty(defaultValue: () -> R): R where C : CharSequence, C : R {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
+    return if (isEmpty()) defaultValue() else this
+}
 
 /**
  * Returns this char sequence if it is not empty and doesn't consist solely of whitespace characters,
@@ -366,8 +371,12 @@ public inline fun <C, R> C.ifEmpty(defaultValue: () -> R): R where C : CharSeque
  */
 @SinceKotlin("1.3")
 @kotlin.internal.InlineOnly
-public inline fun <C, R> C.ifBlank(defaultValue: () -> R): R where C : CharSequence, C : R =
-    if (isBlank()) defaultValue() else this
+public inline fun <C, R> C.ifBlank(defaultValue: () -> R): R where C : CharSequence, C : R {
+    contract {
+        callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+    }
+    return if (isBlank()) defaultValue() else this
+}
 
 /**
  * Returns the range of valid character indices for this char sequence.
diff --git a/libraries/tools/kotlin-stdlib-gen/src/templates/Elements.kt b/libraries/tools/kotlin-stdlib-gen/src/templates/Elements.kt
index 00d2ada9a77..917be8dacd8 100644
--- a/libraries/tools/kotlin-stdlib-gen/src/templates/Elements.kt
+++ b/libraries/tools/kotlin-stdlib-gen/src/templates/Elements.kt
@@ -342,6 +342,9 @@ object Elements : TemplateGroupBase() {
         returns("T")
         body {
             """
+            contract {
+                callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+            }
             if (this is List)
                 return this.getOrElse(index, defaultValue)
             if (index < 0)
@@ -358,6 +361,9 @@ object Elements : TemplateGroupBase() {
         }
         body(Sequences) {
             """
+            contract {
+                callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+            }
             if (index < 0)
                 return defaultValue(index)
             val iterator = iterator()
@@ -374,6 +380,9 @@ object Elements : TemplateGroupBase() {
             inlineOnly()
             body {
                 """
+                contract {
+                    callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+                }
                 return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
                 """
             }
@@ -388,6 +397,9 @@ object Elements : TemplateGroupBase() {
         inlineOnly()
         body {
             """
+            contract {
+                callsInPlace(defaultValue, InvocationKind.AT_MOST_ONCE)
+            }
             return if (index >= 0 && index <= lastIndex) get(index) else defaultValue(index)
             """
         }
diff --git a/libraries/tools/kotlin-stdlib-gen/src/templates/dsl/Writers.kt b/libraries/tools/kotlin-stdlib-gen/src/templates/dsl/Writers.kt
index 9c137f747f0..af266af8a3e 100644
--- a/libraries/tools/kotlin-stdlib-gen/src/templates/dsl/Writers.kt
+++ b/libraries/tools/kotlin-stdlib-gen/src/templates/dsl/Writers.kt
@@ -105,6 +105,7 @@ fun List<MemberBuilder>.writeTo(file: File, targetedSource: TargetedSourceFile)
             }
         }
         if (target.platform == Platform.Common) {
+            writer.appendLine("import kotlin.contracts.*")
             writer.appendLine("import kotlin.random.*")
         }
         if (sourceFile.packageName == "kotlin.collections") {