Handle equality checks for 'when' and data classes

compiler/testData/ir/irText/expressions/floatingPointComparisons/whenByFloatingPoint.kt

@@ -0,0 +1,48 @@
+fun testSimple(x: Double) =
+        when (x) {
+            0.0 -> 0
+            else -> 1
+        }
+
+fun testSmartCastInWhenSubject(x: Any): Int {
+    if (x !is Double) return -1
+    return when (x) {
+        0.0 -> 0
+        else -> 1
+    }
+}
+
+fun testSmartCastInWhenCondition(x: Double, y: Any): Int {
+    if (y !is Double) return -1
+    return when (x) {
+        y -> 0
+        else -> 1
+    }
+}
+
+fun testSmartCastInWhenConditionInBranch(x: Any) =
+    when (x) {
+        !is Double -> -1
+        0.0 -> 0
+        else -> 1
+    }
+
+fun testSmartCastToDifferentTypes(x: Any, y: Any): Int {
+    if (x !is Double) return -1
+    if (y !is Float) return -1
+    return when (x) {
+        y -> 0
+        else -> 1
+    }
+}
+
+fun foo(x: Double) = x
+
+fun testWithPrematureExitInConditionSubexpression(x: Any): Int {
+    return when (x) {
+        foo(
+            if (x !is Double) return 42 else x
+        ) -> 0
+        else -> 1
+    }
+}