[FIR] Pass implications from subject of safe call in DFA

^KT-59689 Fixed

compiler/testData/diagnostics/testsWithStdLib/contracts/smartcasts/returnsImpliesAndSafeCalls.kt

@@ -0,0 +1,71 @@
+// ISSUE: KT-59689
+// FIR_IDENTICAL
+// DIAGNOSTICS: -DEBUG_INFO_SMARTCAST
+// OPT_IN: kotlin.contracts.ExperimentalContracts
+
+import kotlin.contracts.ExperimentalContracts
+import kotlin.contracts.contract
+
+class A {
+    fun returnsTrue(x: Any?): Boolean {
+        contract { returns(true) implies (x is String) }
+        return x is String
+    }
+
+    fun returnsFalse(x: Any?): Boolean {
+        contract { returns(false) implies (x is String) }
+        return x !is String
+    }
+
+    fun returnsNotNull(x: Any?): Any? {
+        contract { returnsNotNull() implies (x is String) }
+        return when (x) {
+            is String -> ""
+            else -> null
+        }
+    }
+
+    fun returnsNull(x: Any?): Any? {
+        contract { returns(null) implies (x is String) }
+        return when (x) {
+            is String -> null
+            else -> ""
+        }
+    }
+}
+
+fun test_returnsTrue(a: A?, s: Any?, b: Boolean) {
+    if (a?.returnsTrue(s) == true) {
+        s.length
+    }
+    if (a?.returnsTrue(s) == true && b) {
+        s.length
+    }
+}
+
+fun test_returnsFalse(a: A?, s: Any?, b: Boolean) {
+    if (a?.returnsFalse(s) == false) {
+        s.length
+    }
+    if (a?.returnsFalse(s) == false && b) {
+        s.length
+    }
+}
+
+fun test_returnsNotNull(a: A?, s: Any?, b: Boolean) {
+    if (a?.returnsNotNull(s) != null) {
+        s.length
+    }
+    if (a?.returnsNotNull(s) != null && b) {
+        s.length
+    }
+}
+
+fun test_returnsNull(a: A?, s: Any?, b: Boolean) {
+    if (a?.returnsNull(s) == null) {
+        s.<!UNRESOLVED_REFERENCE!>length<!> // should be an error
+    }
+    if (a?.returnsNull(s) == null && b) {
+        s.<!UNRESOLVED_REFERENCE!>length<!> // should be an error
+    }
+}