Support distinctBy intermediate call

idea/testData/debugger/sequence/exec/sequence/outs/distinctBy.out

@@ -13,22 +13,22 @@ toList
     after: nothing
 mappings for distinctBy
   direct:
-    1 -> nothing
-    3 -> nothing
-    5 -> nothing
-    6 -> nothing
-    7 -> nothing
-    8 -> nothing
-    9 -> nothing
-    10 -> nothing
-    11 -> nothing
-    12 -> nothing
-    14 -> nothing
+    1 -> 2
+    3 -> 4
+    5 -> 4
+    6 -> 4
+    7 -> 4
+    8 -> 2
+    9 -> 4
+    10 -> 2
+    11 -> 2
+    12 -> 13
+    14 -> 15
   reverse:
-    nothing <- 2
-    nothing <- 4
-    nothing <- 13
-    nothing <- 15
+    1,8,10,11 <- 2
+    3,5,6,7,9 <- 4
+    12 <- 13
+    14 <- 15
 mappings for toList
   direct:
     2 -> nothing
@@ -37,7 +37,6 @@ mappings for toList
     15 -> nothing
   reverse:
     empty
-WRONG!
 Disconnected from the target VM
 
 Process finished with exit code 0

idea/testData/debugger/sequence/exec/sequence/outs/distinctByNullableElement.out

@@ -0,0 +1,32 @@
+LineBreakpoint created at DistinctByNullableElement.kt:5
+Run Java
+Connected to the target VM
+DistinctByNullableElement.kt:5
+sequenceOf(null, 1, 2, 3, null)
+.distinctBy({ it == null })
+.count()
+distinctBy
+    before: 1,3,5,6,7
+    after: 2,4
+count
+    before: 2,4
+    after: nothing
+mappings for distinctBy
+  direct:
+    1 -> 2
+    3 -> 4
+    5 -> 4
+    6 -> 4
+    7 -> 2
+  reverse:
+    1,7 <- 2
+    3,5,6 <- 4
+mappings for count
+  direct:
+    2 -> nothing
+    4 -> nothing
+  reverse:
+    empty
+Disconnected from the target VM
+
+Process finished with exit code 0

idea/testData/debugger/sequence/exec/sequence/outs/distinctByNullableKey.out

@@ -0,0 +1,36 @@
+LineBreakpoint created at DistinctByNullableKey.kt:5
+Run Java
+Connected to the target VM
+DistinctByNullableKey.kt:5
+sequenceOf(1, 2, 3, 4, 5)
+.distinctBy({ if (it % 2 == 0) null else it })
+.count()
+distinctBy
+    before: 1,3,5,7,8
+    after: 2,4,6,9
+count
+    before: 2,4,6,9
+    after: nothing
+mappings for distinctBy
+  direct:
+    1 -> 2
+    3 -> 4
+    5 -> 6
+    7 -> 4
+    8 -> 9
+  reverse:
+    1 <- 2
+    3,7 <- 4
+    5 <- 6
+    8 <- 9
+mappings for count
+  direct:
+    2 -> nothing
+    4 -> nothing
+    6 -> nothing
+    9 -> nothing
+  reverse:
+    empty
+Disconnected from the target VM
+
+Process finished with exit code 0

idea/testData/debugger/sequence/exec/sequence/outs/distinctByNullableKeyAndElement.out

@@ -0,0 +1,35 @@
+LineBreakpoint created at DistinctByNullableKeyAndElement.kt:5
+Run Java
+Connected to the target VM
+DistinctByNullableKeyAndElement.kt:5
+sequenceOf(1, 2, null, null, 3, 1)
+.distinctBy({ if (it == null) 2 else if (it == 3) null else it })
+.count()
+distinctBy
+    before: 1,3,5,6,7,9
+    after: 2,4,8
+count
+    before: 2,4,8
+    after: nothing
+mappings for distinctBy
+  direct:
+    1 -> 2
+    3 -> 4
+    5 -> 4
+    6 -> 4
+    7 -> 8
+    9 -> 2
+  reverse:
+    1,9 <- 2
+    3,5,6 <- 4
+    7 <- 8
+mappings for count
+  direct:
+    2 -> nothing
+    4 -> nothing
+    8 -> nothing
+  reverse:
+    empty
+Disconnected from the target VM
+
+Process finished with exit code 0

idea/testData/debugger/sequence/exec/sequence/src/distinct/DistinctByNullableElement.kt

@@ -0,0 +1,6 @@
+package distinct
+
+fun main(args: Array<String>) {
+  // Breakpoint!
+  sequenceOf(null, 1, 2, 3, null).distinctBy { it == null }.count()
+}

idea/testData/debugger/sequence/exec/sequence/src/distinct/DistinctByNullableKey.kt

@@ -0,0 +1,6 @@
+package distinct
+
+fun main(args: Array<String>) {
+  // Breakpoint!
+  sequenceOf(1, 2, 3, 4, 5).distinctBy { if (it % 2 == 0) null else it }.count()
+}

idea/testData/debugger/sequence/exec/sequence/src/distinct/DistinctByNullableKeyAndElement.kt

@@ -0,0 +1,6 @@
+package distinct
+
+fun main(args: Array<String>) {
+  // Breakpoint!
+  sequenceOf(1, 2, null, null, 3, 1).distinctBy { if (it == null) 2 else if (it == 3) null else it }.count()
+}