KT-351 Distinguish statement and expression positions

compiler/testData/diagnostics/tests/controlFlowAnalysis/kt510.jet

@@ -0,0 +1,18 @@
+//KT-510 `this.` allows initialization without backing field
+
+namespace kt510
+
+public open class Identifier1() {
+    var field : Boolean
+    {
+        field = false; // error
+    }
+}
+
+
+public open class Identifier2() {
+    var field : Boolean
+    {
+        this.field = false;
+    }
+}

compiler/testData/diagnostics/tests/controlFlowAnalysis/kt607.jet

@@ -0,0 +1,18 @@
+//KT-607 Val reassignment is not marked as an error
+
+namespace kt607
+
+fun foo(a: A) {
+    val o = object {
+        val y : Int
+           get() = 42
+    }
+
+    <!VAL_REASSIGNMENT!>a.z<!> = 23
+    <!VAL_REASSIGNMENT!>o.y<!> = 11   //Should be an error here
+}
+
+class A() {
+    val z : Int
+    get() = 3
+}

compiler/testData/diagnostics/tests/controlFlowAnalysis/kt609.jet

@@ -0,0 +1,19 @@
+//KT-609 Analyze not only local variables, but function parameters as well in 'unused values' analysis
+
+namespace kt609
+
+fun test(var a: Int) {
+    a = <!UNUSED_VALUE!>324<!> //should be an 'unused value' warning here
+}
+
+class C() {
+    fun foo(<!UNUSED_PARAMETER!>s<!>: String) {}  //should be an 'unused variable' warning
+}
+
+open class A() {
+    open fun foo(s : String) {}  //should not be a warning
+}
+
+class B() : A() {
+    final override fun foo(s : String) {}  //should not be a warning
+}

compiler/testData/diagnostics/tests/controlFlowAnalysis/kt610.jet

@@ -0,0 +1,10 @@
+//KT-610 Distinguish errors 'unused variable' and 'variable is assigned but never accessed'
+
+namespace kt610
+
+fun foo() {
+    var <!UNUSED_VARIABLE!>j<!> = 9  //'unused variable' error
+
+    var <!ASSIGNED_BUT_NEVER_ACCESSED_VARIABLE!>i<!> = 1  //should be an error 'variable i is assigned but never accessed'
+    i = <!UNUSED_VALUE!>2<!>
+}