[FIR] Fix building callable reference adaptation against flexible types

#KT-45052 Fixed

compiler/fir/analysis-tests/testData/resolveWithStdlib/callableReferences/referenceToJavaStdlib.fir.txt

@@ -0,0 +1,13 @@
+FILE: referenceToJavaStdlib.kt
+    public final fun detectDirsWithTestsMapFileOnly(file: R|java/io/File|): R|kotlin/collections/List<kotlin/String>| {
+        Q|java/nio/file/Files|.R|java/nio/file/Files.walk|(R|<local>/file|.R|java/io/File.toPath|()).R|SubstitutionOverride<java/util/stream/Stream.filter: R|ft<@FlexibleNullability java/util/stream/Stream<ft<@FlexibleNullability java/nio/file/Path, @FlexibleNullability java/nio/file/Path?>!>, java/util/stream/Stream<ft<@FlexibleNullability java/nio/file/Path, @FlexibleNullability java/nio/file/Path?>!>?>!|>|(Q|java/nio/file/Files|::R|java/nio/file/Files.isRegularFile|)
+    }
+    public abstract interface A : R|kotlin/Any| {
+    }
+    public final fun foo(x: R|A|, vararg strings: R|kotlin/Array<out kotlin/String>|): R|kotlin/Unit| {
+    }
+    public final fun takeFunWithA(func: R|(A) -> kotlin/Unit|): R|kotlin/Unit| {
+    }
+    public final fun test(): R|kotlin/Unit| {
+        R|/takeFunWithA|(::R|/foo|)
+    }

compiler/fir/analysis-tests/testData/resolveWithStdlib/callableReferences/referenceToJavaStdlib.kt

@@ -0,0 +1,18 @@
+// ISSUE: KT-45052
+// FULL_JDK
+// JVM_TARGET: 1.8
+
+import java.io.File
+import java.nio.file.Files
+
+fun detectDirsWithTestsMapFileOnly(file: File): List<String> {
+    Files.walk(file.toPath()).filter(Files::isRegularFile)
+}
+
+interface A
+fun foo(x: A, vararg strings: String) {}
+fun takeFunWithA(func: (A) -> Unit) {}
+
+fun test() {
+    takeFunWithA(::foo)
+}

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirDiagnosticTestGenerated.java

@@ -4177,6 +4177,12 @@ public class FirDiagnosticTestGenerated extends AbstractFirDiagnosticTest {
                 runTest("compiler/fir/analysis-tests/testData/resolveWithStdlib/callableReferences/properties.kt");
             }
 
+            @Test
+            @TestMetadata("referenceToJavaStdlib.kt")
+            public void testReferenceToJavaStdlib() throws Exception {
+                runTest("compiler/fir/analysis-tests/testData/resolveWithStdlib/callableReferences/referenceToJavaStdlib.kt");
+            }
+
             @Test
             @TestMetadata("sam.kt")
             public void testSam() throws Exception {

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirDiagnosticsWithLightTreeTestGenerated.java

@@ -4231,6 +4231,12 @@ public class FirDiagnosticsWithLightTreeTestGenerated extends AbstractFirDiagnos
                 runTest("compiler/fir/analysis-tests/testData/resolveWithStdlib/callableReferences/properties.kt");
             }
 
+            @Test
+            @TestMetadata("referenceToJavaStdlib.kt")
+            public void testReferenceToJavaStdlib() throws Exception {
+                runTest("compiler/fir/analysis-tests/testData/resolveWithStdlib/callableReferences/referenceToJavaStdlib.kt");
+            }
+
             @Test
             @TestMetadata("sam.kt")
             public void testSam() throws Exception {

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/CallableReferenceResolution.kt

@@ -97,8 +97,12 @@ private fun buildReflectionType(
         is FirFunction -> {
             val unboundReferenceTarget = if (receiverType != null) 1 else 0
             val callableReferenceAdaptation =
-                context.bodyResolveComponents
-                    .getCallableReferenceAdaptation(context.session, fir, candidate.callInfo.expectedType, unboundReferenceTarget)
+                context.bodyResolveComponents.getCallableReferenceAdaptation(
+                    context.session,
+                    fir,
+                    candidate.callInfo.expectedType?.lowerBoundIfFlexible(),
+                    unboundReferenceTarget
+                )
 
             val parameters = mutableListOf<ConeKotlinType>()