[NI] remove redundant replacing receiver in lambda function descriptor

#KT-30927 Fixed
#KT-31057 Fixed

compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/FirDiagnosticsSmokeTestGenerated.java

@@ -19539,6 +19539,11 @@ public class FirDiagnosticsSmokeTestGenerated extends AbstractFirDiagnosticsSmok
             runTest("compiler/testData/diagnostics/tests/smartCasts/kt30826.kt");
         }
 
+        @TestMetadata("kt30927.kt")
+        public void testKt30927() throws Exception {
+            runTest("compiler/testData/diagnostics/tests/smartCasts/kt30927.kt");
+        }
+
         @TestMetadata("kt3224.kt")
         public void testKt3224() throws Exception {
             runTest("compiler/testData/diagnostics/tests/smartCasts/kt3224.kt");

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/tower/ResolvedAtomCompleter.kt

@@ -208,9 +208,11 @@ class ResolvedAtomCompleter(
 
             val newReceiverValue = receiver.value.replaceType(newValueType)
 
-            functionDescriptor.setExtensionReceiverParameter(
-                ReceiverParameterDescriptorImpl(receiver.containingDeclaration, newReceiverValue, receiver.annotations)
-            )
+            if (newReceiverValue != receiver.value) {
+                functionDescriptor.setExtensionReceiverParameter(
+                    ReceiverParameterDescriptorImpl(receiver.containingDeclaration, newReceiverValue, receiver.annotations)
+                )
+            }
         }
     }
 

compiler/testData/diagnostics/tests/smartCasts/kt30927.kt

@@ -0,0 +1,51 @@
+// !DIAGNOSTICS: -UNUSED_EXPRESSION
+// !WITH_NEW_INFERENCE
+// !CHECK_TYPE
+
+fun case_0() {
+    val z: Any? = 10
+    val y = z.run {
+        this as Int
+        <!NI;DEBUG_INFO_SMARTCAST!>this<!> // error in NI: required Int, found Any?; just inferred to Any? in OI
+    }
+    y checkType { <!NI;DEBUG_INFO_UNRESOLVED_WITH_TARGET, NI;UNRESOLVED_REFERENCE_WRONG_RECEIVER!>_<!><Any?>() }
+    y checkType { <!OI;TYPE_MISMATCH!>_<!><Int>() }
+}
+
+fun case_1(z: Any?) {
+    val y = z.run {
+        when (this) {
+            is String -> return@run <!NI;DEBUG_INFO_SMARTCAST!>this<!> // type mismatch in the new inference (required String, found Any?)
+            is Float -> ""
+            else -> return@run ""
+        }
+    }
+    y checkType { <!NI;DEBUG_INFO_UNRESOLVED_WITH_TARGET, NI;UNRESOLVED_REFERENCE_WRONG_RECEIVER!>_<!><Any?>() }
+    y checkType { <!OI;TYPE_MISMATCH!>_<!><kotlin.String>() }
+    // y is inferred to Any?
+}
+
+fun case_2(z: Any?) {
+    val y = z.run {
+        when (this) {
+            is String -> <!DEBUG_INFO_SMARTCAST!>this<!>
+            is Float -> ""
+            else -> return@run ""
+        }
+    }
+    y checkType { _<kotlin.String>() }
+    // y is inferred to String
+}
+
+fun case_3(z: Any?) {
+    val y = z.let {
+        when (it) {
+            is String -> return@let <!NI;DEBUG_INFO_SMARTCAST!>it<!>
+            is Float -> ""
+            else -> return@let ""
+        }
+    }
+    y checkType { <!NI;DEBUG_INFO_UNRESOLVED_WITH_TARGET, NI;UNRESOLVED_REFERENCE_WRONG_RECEIVER!>_<!><Any?>() }
+    y checkType { <!OI;TYPE_MISMATCH!>_<!><kotlin.String>() }
+    // y is inferred to String
+}

compiler/testData/diagnostics/tests/smartCasts/kt30927.txt

@@ -0,0 +1,6 @@
+package
+
+public fun case_0(): kotlin.Unit
+public fun case_1(/*0*/ z: kotlin.Any?): kotlin.Unit
+public fun case_2(/*0*/ z: kotlin.Any?): kotlin.Unit
+public fun case_3(/*0*/ z: kotlin.Any?): kotlin.Unit

compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java

@@ -19616,6 +19616,11 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                 runTest("compiler/testData/diagnostics/tests/smartCasts/kt30826.kt");
             }
 
+            @TestMetadata("kt30927.kt")
+            public void testKt30927() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/smartCasts/kt30927.kt");
+            }
+
             @TestMetadata("kt3224.kt")
             public void testKt3224() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/smartCasts/kt3224.kt");

compiler/tests/org/jetbrains/kotlin/checkers/javac/DiagnosticsUsingJavacTestGenerated.java

@@ -19541,6 +19541,11 @@ public class DiagnosticsUsingJavacTestGenerated extends AbstractDiagnosticsUsing
                 runTest("compiler/testData/diagnostics/tests/smartCasts/kt30826.kt");
             }
 
+            @TestMetadata("kt30927.kt")
+            public void testKt30927() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/smartCasts/kt30927.kt");
+            }
+
             @TestMetadata("kt3224.kt")
             public void testKt3224() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/smartCasts/kt3224.kt");

core/descriptors/src/org/jetbrains/kotlin/resolve/scopes/receivers/ExtensionReceiver.java

@@ -20,7 +20,20 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.kotlin.descriptors.CallableDescriptor;
 import org.jetbrains.kotlin.types.KotlinType;
+import org.jetbrains.kotlin.types.checker.NewKotlinTypeChecker;
 
+import java.util.Objects;
+
+/**
+ * [ExtensionReceiver] is a receiver for pure `this` call inside lambda with receiver
+ *
+ * x.run {
+ *     this // ExtensionReceiver
+ *     this as String // ExtensionReceiver
+ *     this.toString() // ImplicitClassReceiver
+ *     toString() // ImplicitClassReceiver
+ * }
+ */
 public class ExtensionReceiver extends AbstractReceiverValue implements ImplicitReceiver {
 
     private final CallableDescriptor descriptor;
@@ -43,6 +56,9 @@ public class ExtensionReceiver extends AbstractReceiverValue implements Implicit
     @NotNull
     @Override
     public ReceiverValue replaceType(@NotNull KotlinType newType) {
+        if (NewKotlinTypeChecker.INSTANCE.equalTypes(receiverType, newType)) {
+            return this;
+        }
         return new ExtensionReceiver(descriptor, newType, getOriginal());
     }