diff --git a/analysis/analysis-api-fe10/tests/org/jetbrains/kotlin/analysis/api/fe10/fir/Fe10ResolveCallTestGenerated.java b/analysis/analysis-api-fe10/tests/org/jetbrains/kotlin/analysis/api/fe10/fir/Fe10ResolveCallTestGenerated.java
index b192b5a39d6..6ea7bf9a419 100644
--- a/analysis/analysis-api-fe10/tests/org/jetbrains/kotlin/analysis/api/fe10/fir/Fe10ResolveCallTestGenerated.java
+++ b/analysis/analysis-api-fe10/tests/org/jetbrains/kotlin/analysis/api/fe10/fir/Fe10ResolveCallTestGenerated.java
@@ -771,4 +771,20 @@ public class Fe10ResolveCallTestGenerated extends AbstractResolveCallTest {
     public void testVariableWithMemberInvoke() throws Exception {
         runTest("analysis/analysis-api/testData/components/callResolver/resolveCall/variableWithMemberInvoke.kt");
     }
+
+    @Nested
+    @TestMetadata("analysis/analysis-api/testData/components/callResolver/resolveCall/assignments")
+    @TestDataPath("$PROJECT_ROOT")
+    public class Assignments {
+        @Test
+        public void testAllFilesPresentInAssignments() throws Exception {
+            KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("analysis/analysis-api/testData/components/callResolver/resolveCall/assignments"), Pattern.compile("^(.+)\\.kt$"), null, true);
+        }
+
+        @Test
+        @TestMetadata("insidePlusAssignTarget.kt")
+        public void testInsidePlusAssignTarget() throws Exception {
+            runTest("analysis/analysis-api/testData/components/callResolver/resolveCall/assignments/insidePlusAssignTarget.kt");
+        }
+    }
 }
diff --git a/analysis/analysis-api-fir/tests/org/jetbrains/kotlin/analysis/api/fir/fir/FirResolveCallTestGenerated.java b/analysis/analysis-api-fir/tests/org/jetbrains/kotlin/analysis/api/fir/fir/FirResolveCallTestGenerated.java
index f25b386ceb7..c96f82e56c4 100644
--- a/analysis/analysis-api-fir/tests/org/jetbrains/kotlin/analysis/api/fir/fir/FirResolveCallTestGenerated.java
+++ b/analysis/analysis-api-fir/tests/org/jetbrains/kotlin/analysis/api/fir/fir/FirResolveCallTestGenerated.java
@@ -771,4 +771,20 @@ public class FirResolveCallTestGenerated extends AbstractResolveCallTest {
     public void testVariableWithMemberInvoke() throws Exception {
         runTest("analysis/analysis-api/testData/components/callResolver/resolveCall/variableWithMemberInvoke.kt");
     }
+
+    @Nested
+    @TestMetadata("analysis/analysis-api/testData/components/callResolver/resolveCall/assignments")
+    @TestDataPath("$PROJECT_ROOT")
+    public class Assignments {
+        @Test
+        public void testAllFilesPresentInAssignments() throws Exception {
+            KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("analysis/analysis-api/testData/components/callResolver/resolveCall/assignments"), Pattern.compile("^(.+)\\.kt$"), null, true);
+        }
+
+        @Test
+        @TestMetadata("insidePlusAssignTarget.kt")
+        public void testInsidePlusAssignTarget() throws Exception {
+            runTest("analysis/analysis-api/testData/components/callResolver/resolveCall/assignments/insidePlusAssignTarget.kt");
+        }
+    }
 }
diff --git a/analysis/analysis-api/testData/components/callResolver/resolveCall/assignments/insidePlusAssignTarget.kt b/analysis/analysis-api/testData/components/callResolver/resolveCall/assignments/insidePlusAssignTarget.kt
new file mode 100644
index 00000000000..5e74003d1d2
--- /dev/null
+++ b/analysis/analysis-api/testData/components/callResolver/resolveCall/assignments/insidePlusAssignTarget.kt
@@ -0,0 +1,5 @@
+// WITH_STDLIB
+
+fun foo(x: MutableMap<Int, MutableList<String>>) {
+    x.getOrPut(1) { <expr>mutableListOf</expr><String>() } += "str"
+}
\ No newline at end of file
diff --git a/analysis/analysis-api/testData/components/callResolver/resolveCall/assignments/insidePlusAssignTarget.txt b/analysis/analysis-api/testData/components/callResolver/resolveCall/assignments/insidePlusAssignTarget.txt
new file mode 100644
index 00000000000..e4b61fe9768
--- /dev/null
+++ b/analysis/analysis-api/testData/components/callResolver/resolveCall/assignments/insidePlusAssignTarget.txt
@@ -0,0 +1,12 @@
+KtSuccessCallInfo:
+  call = KtSimpleFunctionCall:
+    isImplicitInvoke = false
+    partiallyAppliedSymbol = KtPartiallyAppliedSymbol:
+      dispatchReceiver = null
+      extensionReceiver = null
+      signature = KtFunctionLikeSignature:
+        receiverType = null
+        returnType = kotlin.collections.MutableList<kotlin.String>
+        symbol = kotlin/collections/mutableListOf(): kotlin.collections.MutableList<T>
+        valueParameters = []
+    argumentMapping = {}
\ No newline at end of file
diff --git a/analysis/low-level-api-fir/testdata/getOrBuildFir/calls/compoundAssignOnVal_lhs.txt b/analysis/low-level-api-fir/testdata/getOrBuildFir/calls/compoundAssignOnVal_lhs.txt
index ca1986c810c..a099458b9e2 100644
--- a/analysis/low-level-api-fir/testdata/getOrBuildFir/calls/compoundAssignOnVal_lhs.txt
+++ b/analysis/low-level-api-fir/testdata/getOrBuildFir/calls/compoundAssignOnVal_lhs.txt
@@ -1,6 +1,6 @@
 KT element: KtNameReferenceExpression
 FIR element: FirPropertyAccessExpressionImpl
-FIR source kind: DesugaredCompoundAssignment
+FIR source kind: KtRealSourceElementKind
 
 FIR element rendered:
 R|<local>/l|
\ No newline at end of file
diff --git a/analysis/low-level-api-fir/testdata/getOrBuildFir/expressions/insidePlusAssignTarget.kt b/analysis/low-level-api-fir/testdata/getOrBuildFir/expressions/insidePlusAssignTarget.kt
new file mode 100644
index 00000000000..45389aff27d
--- /dev/null
+++ b/analysis/low-level-api-fir/testdata/getOrBuildFir/expressions/insidePlusAssignTarget.kt
@@ -0,0 +1,6 @@
+// WITH_STDLIB
+// LOOK_UP_FOR_ELEMENT_OF_TYPE: org.jetbrains.kotlin.psi.KtCallExpression
+
+fun foo(x: MutableMap<Int, MutableList<String>>) {
+    x.getOrPut(1) { <expr>mutableListOf<String>()</expr> } += "str"
+}
\ No newline at end of file
diff --git a/analysis/low-level-api-fir/testdata/getOrBuildFir/expressions/insidePlusAssignTarget.txt b/analysis/low-level-api-fir/testdata/getOrBuildFir/expressions/insidePlusAssignTarget.txt
new file mode 100644
index 00000000000..eb59acd336a
--- /dev/null
+++ b/analysis/low-level-api-fir/testdata/getOrBuildFir/expressions/insidePlusAssignTarget.txt
@@ -0,0 +1,6 @@
+KT element: KtCallExpression
+FIR element: FirFunctionCallImpl
+FIR source kind: KtRealSourceElementKind
+
+FIR element rendered:
+R|kotlin/collections/mutableListOf|<R|kotlin/String|>()
\ No newline at end of file
diff --git a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/GetOrBuildFirTestGenerated.java b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/GetOrBuildFirTestGenerated.java
index da80c66189f..c6162ab22c3 100644
--- a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/GetOrBuildFirTestGenerated.java
+++ b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/GetOrBuildFirTestGenerated.java
@@ -279,6 +279,12 @@ public class GetOrBuildFirTestGenerated extends AbstractGetOrBuildFirTest {
             runTest("analysis/low-level-api-fir/testdata/getOrBuildFir/expressions/ifExpression.kt");
         }
 
+        @Test
+        @TestMetadata("insidePlusAssignTarget.kt")
+        public void testInsidePlusAssignTarget() throws Exception {
+            runTest("analysis/low-level-api-fir/testdata/getOrBuildFir/expressions/insidePlusAssignTarget.kt");
+        }
+
         @Test
         @TestMetadata("intLiteral.kt")
         public void testIntLiteral() throws Exception {
diff --git a/compiler/fir/raw-fir/raw-fir.common/src/org/jetbrains/kotlin/fir/builder/BaseFirBuilder.kt b/compiler/fir/raw-fir/raw-fir.common/src/org/jetbrains/kotlin/fir/builder/BaseFirBuilder.kt
index 056468b50dc..0fb4448ff81 100644
--- a/compiler/fir/raw-fir/raw-fir.common/src/org/jetbrains/kotlin/fir/builder/BaseFirBuilder.kt
+++ b/compiler/fir/raw-fir/raw-fir.common/src/org/jetbrains/kotlin/fir/builder/BaseFirBuilder.kt
@@ -8,7 +8,6 @@ package org.jetbrains.kotlin.fir.builder
 import com.intellij.psi.tree.IElementType
 import org.jetbrains.kotlin.*
 import org.jetbrains.kotlin.KtNodeTypes.*
-import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.Visibilities
 import org.jetbrains.kotlin.fir.*
@@ -919,14 +918,13 @@ abstract class BaseFirBuilder<T>(val baseSession: FirSession, val context: Conte
             return buildAssignmentOperatorStatement {
                 source = baseSource
                 this.operation = operation
-                leftArgument = withDefaultSourceElementKind(KtFakeSourceElementKind.DesugaredCompoundAssignment) {
-                    this@generateAssignment?.convert()
-                } ?: buildErrorExpression {
-                    source = null
-                    diagnostic = ConeSimpleDiagnostic(
-                        "Unsupported left value of assignment: ${baseSource?.psi?.text}", DiagnosticKind.ExpressionExpected
-                    )
-                }
+                leftArgument = this@generateAssignment?.convert()
+                    ?: buildErrorExpression {
+                        source = null
+                        diagnostic = ConeSimpleDiagnostic(
+                            "Unsupported left value of assignment: ${baseSource?.psi?.text}", DiagnosticKind.ExpressionExpected
+                        )
+                    }
                 rightArgument = value
                 this.annotations += annotations
             }