diff --git a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java
index a6dc5e17d78ef8e1284688bb3842c09f7b4e640d..5a68ead15c6dd5d5a6ea3096dfca72b6cfe29f75 100644
--- a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java
+++ b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java
@@ -32152,6 +32152,12 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirDiagnosti
                     runTest("compiler/testData/diagnostics/testsWithStdLib/contracts/fromStdlib/isNullOrEmpty.kt");
                 }
 
+                @Test
+                @TestMetadata("kt45243.kt")
+                public void testKt45243() throws Exception {
+                    runTest("compiler/testData/diagnostics/testsWithStdLib/contracts/fromStdlib/kt45243.kt");
+                }
+
                 @Test
                 @TestMetadata("require.kt")
                 public void testRequire() throws Exception {
diff --git a/compiler/frontend/src/org/jetbrains/kotlin/contracts/ESDataFlowValue.kt b/compiler/frontend/src/org/jetbrains/kotlin/contracts/ESDataFlowValue.kt
index ef85438c13b6fa845dc8944f59a5c41c2277fe31..6b8fd69d3cb952862e0795925a707e5b688d6252 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/contracts/ESDataFlowValue.kt
+++ b/compiler/frontend/src/org/jetbrains/kotlin/contracts/ESDataFlowValue.kt
@@ -78,6 +78,6 @@ class ESReceiverWithDataFlowValue(
  */
 class ESLambda(val lambda: KtLambdaExpression) : AbstractESValue(null) {
     override fun <T> accept(visitor: ESExpressionVisitor<T>): T {
-        throw IllegalStateException("Lambdas shouldn't be visited by ESExpressionVisitor")
+        return visitor.visitLambda(this)
     }
-}
\ No newline at end of file
+}
diff --git a/compiler/resolution/src/org/jetbrains/kotlin/contracts/model/ESExpressionVisitor.kt b/compiler/resolution/src/org/jetbrains/kotlin/contracts/model/ESExpressionVisitor.kt
index 9b54d54651d2e895e1b8d70078718a27e0ec83ef..3815d408c630ecc5f8b6a505667702503b7f4799 100644
--- a/compiler/resolution/src/org/jetbrains/kotlin/contracts/model/ESExpressionVisitor.kt
+++ b/compiler/resolution/src/org/jetbrains/kotlin/contracts/model/ESExpressionVisitor.kt
@@ -30,4 +30,7 @@ interface ESExpressionVisitor<out T> {
     fun visitConstant(esConstant: ESConstant): T
 
     fun visitReceiver(esReceiver: ESReceiver): T
-}
\ No newline at end of file
+
+    // ESLambda is invisible in this module
+    fun visitLambda(lambda: ESValue): T
+}
diff --git a/compiler/resolution/src/org/jetbrains/kotlin/contracts/model/visitors/InfoCollector.kt b/compiler/resolution/src/org/jetbrains/kotlin/contracts/model/visitors/InfoCollector.kt
index 428ff4fb8593327626f33eda20dcbc6d80435cd2..aad613fd532c40d5f61bc1b40abb3ae489b57957 100644
--- a/compiler/resolution/src/org/jetbrains/kotlin/contracts/model/visitors/InfoCollector.kt
+++ b/compiler/resolution/src/org/jetbrains/kotlin/contracts/model/visitors/InfoCollector.kt
@@ -17,10 +17,7 @@
 package org.jetbrains.kotlin.contracts.model.visitors
 
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
-import org.jetbrains.kotlin.contracts.model.ConditionalEffect
-import org.jetbrains.kotlin.contracts.model.ESEffect
-import org.jetbrains.kotlin.contracts.model.ESExpressionVisitor
-import org.jetbrains.kotlin.contracts.model.MutableContextInfo
+import org.jetbrains.kotlin.contracts.model.*
 import org.jetbrains.kotlin.contracts.model.structure.*
 
 class InfoCollector(private val observedEffect: ESEffect, private val builtIns: KotlinBuiltIns) : ESExpressionVisitor<MutableContextInfo> {
@@ -83,6 +80,8 @@ class InfoCollector(private val observedEffect: ESEffect, private val builtIns:
 
     override fun visitReceiver(esReceiver: ESReceiver): MutableContextInfo = MutableContextInfo.EMPTY
 
+    override fun visitLambda(lambda: ESValue): MutableContextInfo = MutableContextInfo.EMPTY
+
     private fun <R> inverted(block: () -> R): R {
         isInverted = isInverted.not()
         val result = block()
diff --git a/compiler/resolution/src/org/jetbrains/kotlin/contracts/model/visitors/Reducer.kt b/compiler/resolution/src/org/jetbrains/kotlin/contracts/model/visitors/Reducer.kt
index 621dfa167b49ec347a76be0b74a1c86bc9776e72..1eb6a0ed9a1cab147ed7522f8aa103d3060d3acd 100644
--- a/compiler/resolution/src/org/jetbrains/kotlin/contracts/model/visitors/Reducer.kt
+++ b/compiler/resolution/src/org/jetbrains/kotlin/contracts/model/visitors/Reducer.kt
@@ -66,8 +66,8 @@ class Reducer(private val builtIns: KotlinBuiltIns) : ESExpressionVisitor<ESExpr
         return ESConstants.booleanValue(result.xor(isOperator.functor.isNegated))
     }
 
-    override fun visitEqual(equal: ESEqual): ESExpression {
-        val reducedLeft = equal.left.accept(this) as ESValue
+    override fun visitEqual(equal: ESEqual): ESExpression? {
+        val reducedLeft = equal.left.accept(this) as ESValue? ?: return null
         val reducedRight = equal.right
 
         if (reducedLeft is ESConstant) return ESConstants.booleanValue((reducedLeft == reducedRight).xor(equal.functor.isNegated))
@@ -114,4 +114,8 @@ class Reducer(private val builtIns: KotlinBuiltIns) : ESExpressionVisitor<ESExpr
     override fun visitConstant(esConstant: ESConstant): ESConstant = esConstant
 
     override fun visitReceiver(esReceiver: ESReceiver): ESReceiver = esReceiver
+
+    override fun visitLambda(lambda: ESValue): ESExpression? {
+        return null
+    }
 }
diff --git a/compiler/resolution/src/org/jetbrains/kotlin/contracts/model/visitors/Substitutor.kt b/compiler/resolution/src/org/jetbrains/kotlin/contracts/model/visitors/Substitutor.kt
index b802e96d154c2a6abf3f4027650afecdd1f3cde5..9a7fd3f93f9d4c45ddbfc484bca516f06d4bad19 100644
--- a/compiler/resolution/src/org/jetbrains/kotlin/contracts/model/visitors/Substitutor.kt
+++ b/compiler/resolution/src/org/jetbrains/kotlin/contracts/model/visitors/Substitutor.kt
@@ -16,10 +16,7 @@
 
 package org.jetbrains.kotlin.contracts.model.visitors
 
-import org.jetbrains.kotlin.contracts.model.Computation
-import org.jetbrains.kotlin.contracts.model.ESExpression
-import org.jetbrains.kotlin.contracts.model.ESExpressionVisitor
-import org.jetbrains.kotlin.contracts.model.ESTypeSubstitution
+import org.jetbrains.kotlin.contracts.model.*
 import org.jetbrains.kotlin.contracts.model.structure.*
 
 /**
@@ -60,9 +57,11 @@ class Substitutor(
         return CallComputation(ESBooleanType, or.functor.invokeWithArguments(left, right))
     }
 
-    override fun visitVariable(esVariable: ESVariable): Computation? = substitutions[esVariable] ?: esVariable
+    override fun visitVariable(esVariable: ESVariable): Computation = substitutions[esVariable] ?: esVariable
 
-    override fun visitConstant(esConstant: ESConstant): Computation? = esConstant
+    override fun visitConstant(esConstant: ESConstant): Computation = esConstant
 
     override fun visitReceiver(esReceiver: ESReceiver): ESReceiver = esReceiver
+
+    override fun visitLambda(lambda: ESValue): Computation = lambda
 }
diff --git a/compiler/testData/diagnostics/testsWithStdLib/contracts/fromStdlib/kt45243.fir.kt b/compiler/testData/diagnostics/testsWithStdLib/contracts/fromStdlib/kt45243.fir.kt
new file mode 100644
index 0000000000000000000000000000000000000000..2d66e085662e54743ee532cd5394c0fa1a5cee7e
--- /dev/null
+++ b/compiler/testData/diagnostics/testsWithStdLib/contracts/fromStdlib/kt45243.fir.kt
@@ -0,0 +1,19 @@
+// ISSUE: KT-45243
+
+import kotlin.contracts.ExperimentalContracts
+import kotlin.contracts.contract
+
+@ExperimentalContracts
+fun <T> assertNotNull(actual: T) {
+    <!WRONG_IMPLIES_CONDITION!>contract { returns() implies (actual != null) }<!>
+}
+
+@ExperimentalContracts
+fun test_1() {
+    assertNotNull { }
+}
+
+@ExperimentalContracts
+fun test_2() {
+    assertNotNull({ })
+}
diff --git a/compiler/testData/diagnostics/testsWithStdLib/contracts/fromStdlib/kt45243.kt b/compiler/testData/diagnostics/testsWithStdLib/contracts/fromStdlib/kt45243.kt
new file mode 100644
index 0000000000000000000000000000000000000000..3059fd542a4e487b3a04f4cff45b9dad4bc3db74
--- /dev/null
+++ b/compiler/testData/diagnostics/testsWithStdLib/contracts/fromStdlib/kt45243.kt
@@ -0,0 +1,19 @@
+// ISSUE: KT-45243
+
+import kotlin.contracts.ExperimentalContracts
+import kotlin.contracts.contract
+
+@ExperimentalContracts
+fun <T> assertNotNull(actual: T) {
+    contract { returns() implies (actual != null) }
+}
+
+@ExperimentalContracts
+fun test_1() {
+    assertNotNull { }
+}
+
+@ExperimentalContracts
+fun test_2() {
+    assertNotNull({ })
+}
diff --git a/compiler/testData/diagnostics/testsWithStdLib/contracts/fromStdlib/kt45243.txt b/compiler/testData/diagnostics/testsWithStdLib/contracts/fromStdlib/kt45243.txt
new file mode 100644
index 0000000000000000000000000000000000000000..69e961eeba8d983bc3f26ceb4deb74495601b441
--- /dev/null
+++ b/compiler/testData/diagnostics/testsWithStdLib/contracts/fromStdlib/kt45243.txt
@@ -0,0 +1,8 @@
+package
+
+@kotlin.contracts.ExperimentalContracts public fun </*0*/ T> assertNotNull(/*0*/ actual: T): kotlin.Unit
+    Returns(WILDCARD) -> actual != null
+
+@kotlin.contracts.ExperimentalContracts public fun test_1(): kotlin.Unit
+@kotlin.contracts.ExperimentalContracts public fun test_2(): kotlin.Unit
+
diff --git a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java
index 8fea46e8a27b289bf5da23f4a36eb40d78832413..6c2f4c9a2e7d8a0c89e504a5c6f2cb8b3ba74c88 100644
--- a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java
+++ b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java
@@ -32248,6 +32248,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                     runTest("compiler/testData/diagnostics/testsWithStdLib/contracts/fromStdlib/isNullOrEmpty.kt");
                 }
 
+                @Test
+                @TestMetadata("kt45243.kt")
+                public void testKt45243() throws Exception {
+                    runTest("compiler/testData/diagnostics/testsWithStdLib/contracts/fromStdlib/kt45243.kt");
+                }
+
                 @Test
                 @TestMetadata("require.kt")
                 public void testRequire() throws Exception {