[FIR] Local variable assignment must be propagated before loops

When performing lookahead for local variable assignments, make sure
assignments taking place within loops are being propagated before loops.
This makes sure smartcasts within non-inline declarations before the
loop are disallowed.

^KT-63867 Fixed

compiler/testData/diagnostics/tests/smartCasts/lambdasWithContracts/lambdaWithCallInPlace.fir.kt

@@ -468,7 +468,7 @@ fun test48() {
     var x: Any = materialize()
     runWithoutContract {
         while (x is String) {
-            x.length
+            <!SMARTCAST_IMPOSSIBLE!>x<!>.length
             x = 10
         }
     }
@@ -536,7 +536,7 @@ fun test55() {
     runWithoutContract {
         for (i in 1..3) {
             require(x is String)
-            x.length
+            <!SMARTCAST_IMPOSSIBLE!>x<!>.length
             x = 10
         }
     }
@@ -619,4 +619,37 @@ fun test63() {
         x?.length ?: -1
         x = null
     }
-}
+}
+
+fun test64() {
+    var x: Any = materialize()
+    require(x is String)
+    runWithoutContract {
+        <!SMARTCAST_IMPOSSIBLE!>x<!>.length
+    }
+    for (i in 1..3) {
+        x = 10
+    }
+}
+
+fun test65() {
+    var x: Any = materialize()
+    require(x is String)
+    atLeastOnce {
+        x.length
+    }
+    for (i in 1..3) {
+        x = 10
+    }
+}
+
+fun test66() {
+    var x: Any = materialize()
+    require(x is String)
+    exactlyOnce {
+        x.length
+    }
+    for (i in 1..3) {
+        x = 10
+    }
+}

compiler/testData/diagnostics/tests/smartCasts/lambdasWithContracts/lambdaWithCallInPlace.kt

@@ -620,3 +620,36 @@ fun test63() {
         x = null
     }
 }
+
+fun test64() {
+    var x: Any = materialize()
+    require(x is String)
+    runWithoutContract {
+        <!SMARTCAST_IMPOSSIBLE!>x<!>.length
+    }
+    for (i in 1..3) {
+        x = 10
+    }
+}
+
+fun test65() {
+    var x: Any = materialize()
+    require(x is String)
+    atLeastOnce {
+        <!SMARTCAST_IMPOSSIBLE!>x<!>.length
+    }
+    for (i in 1..3) {
+        x = 10
+    }
+}
+
+fun test66() {
+    var x: Any = materialize()
+    require(x is String)
+    exactlyOnce {
+        <!SMARTCAST_IMPOSSIBLE!>x<!>.length
+    }
+    for (i in 1..3) {
+        x = 10
+    }
+}