diff --git a/compiler/tests-spec/testData/diagnostics/notLinked/overload-resolution/building-the-overload-candidate-set-ocs/infix-function-call/pos/1.fir.kt b/compiler/tests-spec/testData/diagnostics/notLinked/overload-resolution/building-the-overload-candidate-set-ocs/infix-function-call/pos/1.fir.kt
new file mode 100644
index 00000000000..3612c725935
--- /dev/null
+++ b/compiler/tests-spec/testData/diagnostics/notLinked/overload-resolution/building-the-overload-candidate-set-ocs/infix-function-call/pos/1.fir.kt
@@ -0,0 +1,33 @@
+// !DIAGNOSTICS: -UNUSED_VARIABLE -UNUSED_PARAMETER
+// SKIP_TXT
+
+/*
+ * KOTLIN DIAGNOSTICS NOT LINKED SPEC TEST (POSITIVE)
+ *
+ * SECTIONS: overload-resolution, building-the-overload-candidate-set-ocs, infix-function-call
+ * NUMBER: 1
+ * DESCRIPTION: Not null Smartcast doesn't work in case of property infix call
+ * UNEXPECTED BEHAVIOUR
+ * ISSUES: KT-36786
+ */
+
+class C() {
+    infix operator fun invoke(i: Int) { } //(1)
+}
+
+class B(val memberValCNull: C? = null) {
+    infix fun bar(i: Int) {}
+}
+
+// TESTCASE NUMBER: 1
+fun case1() {
+    val b: B = B()
+//    b memberValCNull 1                 //nok  (UNSAFE_INFIX_CALL)
+//    b.memberValCNull.invoke(1)         //nok (UNSAFE_CALL)
+
+    if (b.memberValCNull != null) {
+        b memberValCNull 1            //nok  (UNSAFE_INFIX_CALL) !!!!
+        b.memberValCNull.invoke(2)    //ok
+        b.memberValCNull(3)           //nok (UNSAFE_CALL)  !!!
+    }
+}
diff --git a/compiler/tests-spec/testData/diagnostics/notLinked/overload-resolution/building-the-overload-candidate-set-ocs/infix-function-call/pos/2.fir.kt b/compiler/tests-spec/testData/diagnostics/notLinked/overload-resolution/building-the-overload-candidate-set-ocs/infix-function-call/pos/2.fir.kt
new file mode 100644
index 00000000000..c4a64045bd7
--- /dev/null
+++ b/compiler/tests-spec/testData/diagnostics/notLinked/overload-resolution/building-the-overload-candidate-set-ocs/infix-function-call/pos/2.fir.kt
@@ -0,0 +1,33 @@
+// !DIAGNOSTICS: -UNUSED_VARIABLE -UNUSED_PARAMETER
+// SKIP_TXT
+
+/*
+ * KOTLIN DIAGNOSTICS NOT LINKED SPEC TEST (POSITIVE)
+ *
+ * SECTIONS: overload-resolution, building-the-overload-candidate-set-ocs, infix-function-call
+ * NUMBER: 2
+ * DESCRIPTION: is-check Smartcast doesn't work in case of property infix call
+ * UNEXPECTED BEHAVIOUR
+ * ISSUES: KT-36786
+ */
+
+class B(val memberVal: Any)
+class C() {
+    infix operator fun invoke(i: Int) { } //(1)
+}
+// TESTCASE NUMBER: 1
+fun case1() {
+    val b: B = B(C())
+    b <!UNRESOLVED_REFERENCE!>memberVal<!> 1           //nok UNRESOLVED_REFERENCE
+    b.memberVal.<!UNRESOLVED_REFERENCE!>invoke<!>(2)   //nok UNRESOLVED_REFERENCE
+    b.<!UNRESOLVED_REFERENCE!>memberVal<!>(1)          //nok FUNCTION_EXPECTED
+
+    if (b.memberVal is C) {
+
+        b memberVal 1           //nok UNRESOLVED_REFERENCE !!!!
+        b.memberVal.invoke(1)   //ok
+
+        b.memberVal(1)          //nok FUNCTION_EXPECTED  !!!
+        (b.memberVal)(1)        //ok
+    }
+}
diff --git a/compiler/tests-spec/testData/diagnostics/notLinked/overload-resolution/building-the-overload-candidate-set-ocs/infix-function-call/pos/3.fir.kt b/compiler/tests-spec/testData/diagnostics/notLinked/overload-resolution/building-the-overload-candidate-set-ocs/infix-function-call/pos/3.fir.kt
new file mode 100644
index 00000000000..0247b3edd17
--- /dev/null
+++ b/compiler/tests-spec/testData/diagnostics/notLinked/overload-resolution/building-the-overload-candidate-set-ocs/infix-function-call/pos/3.fir.kt
@@ -0,0 +1,34 @@
+// !DIAGNOSTICS: -UNUSED_VARIABLE -UNUSED_PARAMETER
+// SKIP_TXT
+
+/*
+ * KOTLIN DIAGNOSTICS NOT LINKED SPEC TEST (POSITIVE)
+ *
+ * SECTIONS: overload-resolution, building-the-overload-candidate-set-ocs, infix-function-call
+ * NUMBER: 3
+ * DESCRIPTION: "Unsafe" cast doesn't work in case of property infix call
+ * UNEXPECTED BEHAVIOUR
+ * ISSUES: KT-36786
+ */
+
+class B(val memberVal: Any)
+class C() {
+    infix operator fun invoke(i: Int) { } //(1)
+}
+
+// TESTCASE NUMBER: 1
+fun case1() {
+    val b: B = B(C())
+    b <!UNRESOLVED_REFERENCE!>memberVal<!> 1           //nok UNRESOLVED_REFERENCE
+    b.memberVal.<!UNRESOLVED_REFERENCE!>invoke<!>(2)   //nok UNRESOLVED_REFERENCE
+    b.<!UNRESOLVED_REFERENCE!>memberVal<!>(1)          //nok FUNCTION_EXPECTED
+
+    b.memberVal as C
+
+    b memberVal 1           //nok UNRESOLVED_REFERENCE !!!!
+    b.memberVal.invoke(1)   //ok
+
+    b.memberVal(1)          //nok FUNCTION_EXPECTED  !!!
+    (b.memberVal)(1)        //ok
+
+}
diff --git a/compiler/tests-spec/testData/diagnostics/notLinked/overload-resolution/building-the-overload-candidate-set-ocs/infix-function-call/pos/4.fir.kt b/compiler/tests-spec/testData/diagnostics/notLinked/overload-resolution/building-the-overload-candidate-set-ocs/infix-function-call/pos/4.fir.kt
new file mode 100644
index 00000000000..b2aa4430e9d
--- /dev/null
+++ b/compiler/tests-spec/testData/diagnostics/notLinked/overload-resolution/building-the-overload-candidate-set-ocs/infix-function-call/pos/4.fir.kt
@@ -0,0 +1,109 @@
+// !DIAGNOSTICS: -UNUSED_VARIABLE -UNUSED_PARAMETER
+// SKIP_TXT
+
+/*
+ * KOTLIN DIAGNOSTICS NOT LINKED SPEC TEST (POSITIVE)
+ *
+ * SECTIONS: overload-resolution, building-the-overload-candidate-set-ocs, infix-function-call
+ * NUMBER: 4
+ * DESCRIPTION: Local extension infix extension callables
+ * UNEXPECTED BEHAVIOUR
+ * ISSUES: KT-36786
+ */
+
+
+// TESTCASE NUMBER: 1, 2
+// FILE: infixLib.kt
+package libPackage
+
+class C() {
+    infix operator fun invoke(i: Int) {}
+}
+
+class B() {
+    val barC: C = TODO()
+    val B.barC: C
+    get() = TODO()
+
+    infix fun fooC(i: Int) = {}
+    infix fun B.fooC(i: Int) =
+    {}
+}
+
+infix fun B.fooC(i: Int) = {}
+val B.barC: C
+get() = TODO()
+
+
+// FILE: TestCase1.kt
+/*
+ * TESTCASE NUMBER: 1
+ * NOTE: should be resolved to member properties, others should be shadowed by member function
+ */
+package testPackInfix
+import libPackage.C
+import libPackage.B
+import libPackage.*
+
+
+fun case1() {
+    class Case() {
+        val B.barC: C
+        get() = TODO()
+
+        fun case() {
+            val b = B()
+            <!DEBUG_INFO_CALL("fqName: libPackage.B.fooC; typeCall: infix function")!>b fooC 3<!>
+            <!DEBUG_INFO_CALL("fqName: libPackage.C.invoke; typeCall: variable&invoke")!>b barC 3<!>
+        }
+    }
+
+    fun case() {
+        val b = B()
+        <!DEBUG_INFO_CALL("fqName: libPackage.B.fooC; typeCall: infix function")!>b fooC 3<!>
+        <!DEBUG_INFO_CALL("fqName: libPackage.C.invoke; typeCall: variable&invoke")!>b barC 3<!>
+    }
+}
+
+// FILE: TestCase2.kt
+/*
+ * TESTCASE NUMBER: 2
+ * NOTE: should be resolved to member properties, others should be shadowed by member property with invoke or by member function
+ */
+package testPackInfix
+import libPackage.C
+import libPackage.B
+import libPackage.*
+import libPackage.fooC
+import libPackage.barC
+
+/*should be shadowed by member function*/
+infix fun B.fooC(i: Int) = {}
+/*should be shadowed by member property with invoke*/
+infix fun B.barC(i: Int) = {}
+/*should be shadowed by member property*/
+val B.barC: C
+get() = TODO()
+
+fun case2() {
+    class Case() {
+        /*should be shadowed by member property*/
+        val B.barC: C
+        get() = TODO()
+        /*should be shadowed by member property with invoke*/
+        infix fun B.barC(i: Int) = {}
+        /*should be shadowed by member function*/
+        infix fun B.fooC(i: Int) = {}
+        fun case() {
+            val b = B()
+            <!DEBUG_INFO_CALL("fqName: libPackage.B.fooC; typeCall: infix function")!>b fooC 3<!>
+            <!DEBUG_INFO_CALL("fqName: libPackage.C.invoke; typeCall: variable&invoke")!>b barC 3<!>
+        }
+    }
+
+    fun case() {
+        val b = B()
+        <!DEBUG_INFO_CALL("fqName: libPackage.B.fooC; typeCall: infix function")!>b fooC 3<!>
+        <!DEBUG_INFO_CALL("fqName: libPackage.C.invoke; typeCall: variable&invoke")!>b barC 3<!>
+    }
+}