[tests] Klib based signature clash improve coverage for KT-63670

compiler/testData/diagnostics/klibSerializationTests/signatureClashClasses.kt

@@ -0,0 +1,31 @@
+// WITH_STDLIB
+// DIAGNOSTICS: -ERROR_SUPPRESSION
+// FIR_IDENTICAL
+// RENDER_ALL_DIAGNOSTICS_FULL_TEXT
+
+// IGNORE_BACKEND: JS_IR, NATIVE
+// ^ KT-65680: Class redeclaration leads to BackendException during IR fake override builder
+
+// MODULE: lib
+package com.example.klib.serialization.diagnostics
+
+class SeparateModules
+
+// MODULE: main(lib)
+// FILE: foo.kt
+package com.example.klib.serialization.diagnostics
+
+class SeparateModules
+
+<!CONFLICTING_KLIB_SIGNATURES_ERROR, CONFLICTING_KLIB_SIGNATURES_ERROR!>@Suppress("PACKAGE_OR_CLASSIFIER_REDECLARATION") class SeparateFiles<!>
+
+// FILE: main.kt
+package com.example.klib.serialization.diagnostics
+
+<!CONFLICTING_KLIB_SIGNATURES_ERROR, CONFLICTING_KLIB_SIGNATURES_ERROR!>@Suppress("PACKAGE_OR_CLASSIFIER_REDECLARATION") class SeparateFiles<!>
+
+class ConstructorsClash {
+    <!CONFLICTING_KLIB_SIGNATURES_ERROR!>@Deprecated(message = "", level = DeprecationLevel.HIDDEN)
+    constructor(s: Int)<!>
+    <!CONFLICTING_KLIB_SIGNATURES_ERROR!>constructor(s: Int)<!>
+}