Accurate representation of smart casts on complex expressions

compiler/testData/diagnostics/tests/smartCasts/smartCastOnIf.kt

@@ -0,0 +1,10 @@
+fun baz(s: String?): Int {
+    return <!DEBUG_INFO_SMARTCAST!>if (s == null) {
+        ""
+    }
+    else {
+        val u: String? = null
+        if (u == null) return 0
+        u
+    }<!>.length
+}

compiler/testData/diagnostics/tests/smartCasts/smartCastOnIf.txt

@@ -0,0 +1,3 @@
+package
+
+public fun baz(/*0*/ s: kotlin.String?): kotlin.Int

compiler/testData/diagnostics/tests/smartCasts/smartCastOnWhen.kt

@@ -0,0 +1,20 @@
+// Smart casts on complex expressions
+fun baz(s: String?): Int {
+    if (s == null) return 0
+    return <!DEBUG_INFO_SMARTCAST!>when(<!DEBUG_INFO_SMARTCAST!>s<!>) {
+        "abc" -> s
+        else -> "xyz"
+    }<!>.length
+}
+
+var ss: String? = null
+
+fun bar(): Int {
+    if (ss == null) return 0
+    // ss cannot be smart casted, so an error here
+    return when(ss) {
+        "abc" -> ss
+        else -> "xyz"
+    }<!UNSAFE_CALL!>.<!>length
+}
+

compiler/testData/diagnostics/tests/smartCasts/smartCastOnWhen.txt

@@ -0,0 +1,5 @@
+package
+
+public var ss: kotlin.String?
+public fun bar(): kotlin.Int
+public fun baz(/*0*/ s: kotlin.String?): kotlin.Int