Smart casts inside property chains like a?.b?.c.foo(a, b) are now handled correctly #KT-7290 Fixed

compiler/testData/diagnostics/tests/smartCasts/safecalls/propertyChain.kt

@@ -0,0 +1,14 @@
+// See KT-7290
+class MyClass(val x: String?)
+fun foo(y: MyClass?): Int {
+    // x here is smartcast but y is not
+    val z = y?.x?.subSequence(0, <!DEBUG_INFO_SMARTCAST!><!DEBUG_INFO_SMARTCAST!>y<!>.x<!>.length)
+    // !! is necessary here
+    y!!.x
+    return z?.length ?: -1
+}
+fun bar(y: MyClass?) {
+    y?.x!!.length
+    // !! is necessary here
+    y!!.x
+}