diff --git a/compiler/testData/codegen/box/builderInference/issues/kt60291a.kt b/compiler/testData/codegen/box/builderInference/issues/kt60291a.kt
new file mode 100644
index 00000000000..0b31efc5719
--- /dev/null
+++ b/compiler/testData/codegen/box/builderInference/issues/kt60291a.kt
@@ -0,0 +1,32 @@
+// ISSUE: KT-60291
+// WITH_STDLIB
+
+// IGNORE_LIGHT_ANALYSIS
+// IGNORE_BACKEND: ANY
+// REASON: red code in K1 (see corresponding diagnostic test)
+// REASON: compile-time failure in K2/JVM (java.lang.IllegalStateException: Cannot serialize error type: ERROR CLASS: Cannot infer argument for type parameter PTV)
+// REASON: compile-time failure in K2/Native, K2/WASM, K2/JS (org.jetbrains.kotlin.backend.common.linkage.issues.IrDisallowedErrorNode: Class found but error nodes are not allowed)
+
+fun box(): String {
+    selectBuildee(
+        build { setTypeVariable(TargetType()) },
+        build {}
+    )
+    return "OK"
+}
+
+
+
+
+fun <T> selectBuildee(vararg values: Buildee<T>): Buildee<T> = values.first()
+
+class TargetType
+
+class Buildee<TV> {
+    fun setTypeVariable(value: TV) { storage = value }
+    private var storage: TV = TargetType() as TV
+}
+
+fun <PTV> build(instructions: Buildee<PTV>.() -> Unit): Buildee<PTV> {
+    return Buildee<PTV>().apply(instructions)
+}
diff --git a/compiler/testData/codegen/box/builderInference/issues/kt60291b.kt b/compiler/testData/codegen/box/builderInference/issues/kt60291b.kt
new file mode 100644
index 00000000000..6bf3077aa1f
--- /dev/null
+++ b/compiler/testData/codegen/box/builderInference/issues/kt60291b.kt
@@ -0,0 +1,30 @@
+// ISSUE: KT-60291
+
+// IGNORE_LIGHT_ANALYSIS
+// IGNORE_BACKEND_K1: ANY
+// REASON: red code (see corresponding diagnostic test)
+
+// IGNORE_BACKEND_K2: NATIVE, WASM, JS_IR, JS_IR_ES6
+// REASON: compile-time failure (org.jetbrains.kotlin.backend.common.linkage.issues.IrDisallowedErrorNode: Class found but error nodes are not allowed)
+
+fun box(): String {
+    if (true)
+        build { setTypeVariable(TargetType()) }
+    else
+        build {}
+    return "OK"
+}
+
+
+
+
+class TargetType
+
+class Buildee<TV> {
+    fun setTypeVariable(value: TV) { storage = value }
+    private var storage: TV = TargetType() as TV
+}
+
+fun <PTV> build(instructions: Buildee<PTV>.() -> Unit): Buildee<PTV> {
+    return Buildee<PTV>().apply(instructions)
+}
diff --git a/compiler/testData/codegen/box/builderInference/issues/kt60291c.kt b/compiler/testData/codegen/box/builderInference/issues/kt60291c.kt
new file mode 100644
index 00000000000..b29a8f401c2
--- /dev/null
+++ b/compiler/testData/codegen/box/builderInference/issues/kt60291c.kt
@@ -0,0 +1,30 @@
+// ISSUE: KT-60291
+
+// IGNORE_LIGHT_ANALYSIS
+// IGNORE_BACKEND: ANY
+// REASON: red code in K1 (see corresponding diagnostic test)
+// REASON: compile-time failure in K2/JVM (java.lang.IllegalStateException: Cannot serialize error type: ERROR CLASS: Cannot infer argument for type parameter PTV)
+// REASON: compile-time failure in K2/Native, K2/WASM, K2/JS (org.jetbrains.kotlin.backend.common.linkage.issues.IrDisallowedErrorNode: Class found but error nodes are not allowed)
+
+fun box(): String {
+    when ("") {
+        "true" -> build { setTypeVariable(TargetType()) }
+        "false" -> build {}
+        else -> Buildee()
+    }
+    return "OK"
+}
+
+
+
+
+class TargetType
+
+class Buildee<TV> {
+    fun setTypeVariable(value: TV) { storage = value }
+    private var storage: TV = TargetType() as TV
+}
+
+fun <PTV> build(instructions: Buildee<PTV>.() -> Unit): Buildee<PTV> {
+    return Buildee<PTV>().apply(instructions)
+}
diff --git a/compiler/testData/diagnostics/tests/builderInference/issues/kt60291a.fir.kt b/compiler/testData/diagnostics/tests/builderInference/issues/kt60291a.fir.kt
new file mode 100644
index 00000000000..560e7995c99
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/builderInference/issues/kt60291a.fir.kt
@@ -0,0 +1,29 @@
+// ISSUE: KT-60291
+// CHECK_TYPE_WITH_EXACT
+// WITH_STDLIB
+
+fun test() {
+    val buildee = selectBuildee(
+        build { setTypeVariable(TargetType()) },
+        build {}
+    )
+    // exact type equality check — turns unexpected compile-time behavior into red code
+    // considered to be non-user-reproducible code for the purposes of these tests
+    checkExactType<Buildee<TargetType>>(buildee)
+}
+
+
+
+
+fun <T> selectBuildee(vararg values: Buildee<T>): Buildee<T> = values.first()
+
+class TargetType
+
+class Buildee<TV> {
+    fun setTypeVariable(value: TV) { storage = value }
+    private var storage: TV = null!!
+}
+
+fun <PTV> build(instructions: Buildee<PTV>.() -> Unit): Buildee<PTV> {
+    return Buildee<PTV>().apply(instructions)
+}
diff --git a/compiler/testData/diagnostics/tests/builderInference/issues/kt60291a.kt b/compiler/testData/diagnostics/tests/builderInference/issues/kt60291a.kt
new file mode 100644
index 00000000000..8477c928387
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/builderInference/issues/kt60291a.kt
@@ -0,0 +1,29 @@
+// ISSUE: KT-60291
+// CHECK_TYPE_WITH_EXACT
+// WITH_STDLIB
+
+fun test() {
+    val buildee = selectBuildee(
+        build <!BUILDER_INFERENCE_MULTI_LAMBDA_RESTRICTION!>{ setTypeVariable(TargetType()) }<!>,
+        build <!BUILDER_INFERENCE_MULTI_LAMBDA_RESTRICTION!>{}<!>
+    )
+    // exact type equality check — turns unexpected compile-time behavior into red code
+    // considered to be non-user-reproducible code for the purposes of these tests
+    checkExactType<Buildee<TargetType>>(buildee)
+}
+
+
+
+
+fun <T> selectBuildee(vararg values: Buildee<T>): Buildee<T> = values.first()
+
+class TargetType
+
+class Buildee<TV> {
+    fun setTypeVariable(value: TV) { storage = value }
+    private var storage: TV = null!!
+}
+
+fun <PTV> build(instructions: Buildee<PTV>.() -> Unit): Buildee<PTV> {
+    return Buildee<PTV>().apply(instructions)
+}
diff --git a/compiler/testData/diagnostics/tests/builderInference/issues/kt60291b.fir.kt b/compiler/testData/diagnostics/tests/builderInference/issues/kt60291b.fir.kt
new file mode 100644
index 00000000000..385a9dd2e7c
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/builderInference/issues/kt60291b.fir.kt
@@ -0,0 +1,26 @@
+// ISSUE: KT-60291
+// CHECK_TYPE_WITH_EXACT
+
+fun test() {
+    val buildee = if (true)
+        build { setTypeVariable(TargetType()) }
+    else
+        build {}
+    // exact type equality check — turns unexpected compile-time behavior into red code
+    // considered to be non-user-reproducible code for the purposes of these tests
+    checkExactType<Buildee<TargetType>>(buildee)
+}
+
+
+
+
+class TargetType
+
+class Buildee<TV> {
+    fun setTypeVariable(value: TV) { storage = value }
+    private var storage: TV = null!!
+}
+
+fun <PTV> build(instructions: Buildee<PTV>.() -> Unit): Buildee<PTV> {
+    return Buildee<PTV>().apply(instructions)
+}
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/builderInference/issues/kt60291b.kt b/compiler/testData/diagnostics/tests/builderInference/issues/kt60291b.kt
new file mode 100644
index 00000000000..0179a242c2f
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/builderInference/issues/kt60291b.kt
@@ -0,0 +1,26 @@
+// ISSUE: KT-60291
+// CHECK_TYPE_WITH_EXACT
+
+fun test() {
+    val buildee = if (true)
+        build <!BUILDER_INFERENCE_MULTI_LAMBDA_RESTRICTION!>{ setTypeVariable(TargetType()) }<!>
+    else
+        build <!BUILDER_INFERENCE_MULTI_LAMBDA_RESTRICTION!>{}<!>
+    // exact type equality check — turns unexpected compile-time behavior into red code
+    // considered to be non-user-reproducible code for the purposes of these tests
+    checkExactType<Buildee<TargetType>>(buildee)
+}
+
+
+
+
+class TargetType
+
+class Buildee<TV> {
+    fun setTypeVariable(value: TV) { storage = value }
+    private var storage: TV = null!!
+}
+
+fun <PTV> build(instructions: Buildee<PTV>.() -> Unit): Buildee<PTV> {
+    return Buildee<PTV>().apply(instructions)
+}
diff --git a/compiler/testData/diagnostics/tests/builderInference/issues/kt60291c.fir.kt b/compiler/testData/diagnostics/tests/builderInference/issues/kt60291c.fir.kt
new file mode 100644
index 00000000000..d21082a4410
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/builderInference/issues/kt60291c.fir.kt
@@ -0,0 +1,27 @@
+// ISSUE: KT-60291
+// CHECK_TYPE_WITH_EXACT
+
+fun test() {
+    val buildee = when ("") {
+        "true" -> build { setTypeVariable(TargetType()) }
+        "false" -> build {}
+        else -> Buildee()
+    }
+    // exact type equality check — turns unexpected compile-time behavior into red code
+    // considered to be non-user-reproducible code for the purposes of these tests
+    checkExactType<Buildee<TargetType>>(buildee)
+}
+
+
+
+
+class TargetType
+
+class Buildee<TV> {
+    fun setTypeVariable(value: TV) { storage = value }
+    private var storage: TV = null!!
+}
+
+fun <PTV> build(instructions: Buildee<PTV>.() -> Unit): Buildee<PTV> {
+    return Buildee<PTV>().apply(instructions)
+}
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/builderInference/issues/kt60291c.kt b/compiler/testData/diagnostics/tests/builderInference/issues/kt60291c.kt
new file mode 100644
index 00000000000..3164082d6cc
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/builderInference/issues/kt60291c.kt
@@ -0,0 +1,27 @@
+// ISSUE: KT-60291
+// CHECK_TYPE_WITH_EXACT
+
+fun test() {
+    val buildee = when ("") {
+        "true" -> build <!BUILDER_INFERENCE_MULTI_LAMBDA_RESTRICTION!>{ setTypeVariable(TargetType()) }<!>
+        "false" -> build <!BUILDER_INFERENCE_MULTI_LAMBDA_RESTRICTION!>{}<!>
+        else -> Buildee()
+    }
+    // exact type equality check — turns unexpected compile-time behavior into red code
+    // considered to be non-user-reproducible code for the purposes of these tests
+    checkExactType<Buildee<TargetType>>(buildee)
+}
+
+
+
+
+class TargetType
+
+class Buildee<TV> {
+    fun setTypeVariable(value: TV) { storage = value }
+    private var storage: TV = null!!
+}
+
+fun <PTV> build(instructions: Buildee<PTV>.() -> Unit): Buildee<PTV> {
+    return Buildee<PTV>().apply(instructions)
+}