Implementation of smart casts for public / protected immutable properties that are not open and used in the same module.

DataFlowValueFactory and its environment refactoring: containing declaration is added into factory functions
as an argument and used to determine identifier stability. A few minor fixes. #KT-5907 Fixed. #KT-4450 Fixed. #KT-4409 Fixed.

New tests for KT-4409, KT-4450, KT-5907 (public and protected value properties used from the same module or not,
open properties, variable properties, delegated properties, properties with non-default getter).
Public val test and KT-362 test changed accordingly.

compiler/testData/diagnostics/tests/nullabilityAndSmartCasts/kt362.kt

@@ -5,8 +5,8 @@ package example
 
 fun test() {
   val p = test.Public()
-  if (p.public is Int) <!SMARTCAST_IMPOSSIBLE!>p.public<!> + 1
-  if (p.<!INVISIBLE_MEMBER!>protected<!> is Int) <!SMARTCAST_IMPOSSIBLE!>p.<!INVISIBLE_MEMBER!>protected<!><!> + 1
+  if (p.public is Int) <!DEBUG_INFO_SMARTCAST!>p.public<!> + 1
+  if (p.<!INVISIBLE_MEMBER!>protected<!> is Int) <!DEBUG_INFO_SMARTCAST!>p.<!INVISIBLE_MEMBER!>protected<!><!> + 1
   if (p.internal is Int) <!DEBUG_INFO_SMARTCAST!>p.internal<!> + 1
   val i = test.Internal()
   if (i.public is Int) <!DEBUG_INFO_SMARTCAST!>i.public<!> + 1

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

@@ -1,10 +1,11 @@
-public class A() {
-    public val foo: Int? = 1
+public open class A() {
+    public open val foo: Int? = 1
 }
 
 fun Int.bar(i: Int) = i
 
 fun test() {
     val p = A()
+    // For open value properties, smart casts should not work
     if (p.foo is Int) <!SMARTCAST_IMPOSSIBLE!>p.foo<!> bar 11
 }

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

@@ -3,9 +3,9 @@ package
 internal fun test(): kotlin.Unit
 internal fun kotlin.Int.bar(/*0*/ i: kotlin.Int): kotlin.Int
 
-public final class A {
+public open class A {
     public constructor A()
-    public final val foo: kotlin.Int? = 1
+    public open val foo: kotlin.Int? = 1
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String

compiler/testData/diagnostics/tests/smartCasts/varnotnull/kt4409.kt

@@ -0,0 +1,13 @@
+public trait A {
+    public val x: Any
+}
+
+public class B(override public val x: Any) : A {
+    fun foo(): Int {
+        if (x is String) {
+            return <!DEBUG_INFO_SMARTCAST!>x<!>.length()
+        } else {
+            return 0
+        }
+    }
+}

compiler/testData/diagnostics/tests/smartCasts/varnotnull/kt4409.txt

@@ -0,0 +1,17 @@
+package
+
+public trait A {
+    public abstract val x: kotlin.Any
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class B : A {
+    public constructor B(/*0*/ x: kotlin.Any)
+    public open override /*1*/ val x: kotlin.Any
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    internal final fun foo(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/smartCasts/varnotnull/kt5907.kt

@@ -0,0 +1,12 @@
+public class X {
+    public val x : String? = null
+    public fun fn(): Int {
+        if (x != null)
+            // Smartcast is possible because it's value property with default getter
+            // used in the same module
+            return <!DEBUG_INFO_SMARTCAST!>x<!>.length() 
+        else
+            return 0
+    }
+}
+

compiler/testData/diagnostics/tests/smartCasts/varnotnull/kt5907.txt

@@ -0,0 +1,10 @@
+package
+
+public final class X {
+    public constructor X()
+    public final val x: kotlin.String? = null
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final fun fn(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/smartCasts/varnotnull/kt5907customGetter.kt

@@ -0,0 +1,13 @@
+public class X {
+    private val x : String? = null
+    public val y: CharSequence?
+        get() = x?.subSequence(0, 1)
+    public fun fn(): Int {
+        if (y != null)
+            // With non-default getter smartcast is not possible
+            return y<!UNSAFE_CALL!>.<!>length() 
+        else
+            return 0
+    }
+}
+

compiler/testData/diagnostics/tests/smartCasts/varnotnull/kt5907customGetter.txt

@@ -0,0 +1,11 @@
+package
+
+public final class X {
+    public constructor X()
+    private final val x: kotlin.String? = null
+    public final val y: kotlin.CharSequence?
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final fun fn(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/smartCasts/varnotnull/kt5907delegate.kt

@@ -0,0 +1,22 @@
+class Delegate {
+    fun get(thisRef: Any?, prop: PropertyMetadata): String? {
+        return null
+    }
+}
+
+class Example {
+    private val p: String? by Delegate()
+
+    public val r: String? = "xyz"
+
+    public fun foo(): String {
+        // Smart cast is not possible if property is delegated
+        return if (p != null) <!TYPE_MISMATCH!>p<!> else ""
+    }
+
+    public fun bar(): String {
+        // But is possible for non-delegated value property even if it's public
+        return if (r != null) <!DEBUG_INFO_SMARTCAST!>r<!> else ""
+    }
+}
+

compiler/testData/diagnostics/tests/smartCasts/varnotnull/kt5907delegate.txt

@@ -0,0 +1,20 @@
+package
+
+internal final class Delegate {
+    public constructor Delegate()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    internal final fun get(/*0*/ thisRef: kotlin.Any?, /*1*/ prop: kotlin.PropertyMetadata): kotlin.String?
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+internal final class Example {
+    public constructor Example()
+    private final val p: kotlin.String?
+    public final val r: kotlin.String? = "xyz"
+    public final fun bar(): kotlin.String
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final fun foo(): kotlin.String
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/smartCasts/varnotnull/kt5907otherModule.kt

@@ -0,0 +1,35 @@
+// MODULE: m1
+// FILE: a.kt
+
+package a
+
+public class X {
+    public val x : String? = null
+}
+
+// MODULE: m2(m1)
+// FILE: b.kt
+
+package b
+
+import a.X
+
+public fun X.gav(): Int {
+    if (x != null)
+        // Smart cast is not possible if definition is in another module
+        return x<!UNSAFE_CALL!>.<!>length()
+    else
+        return 0
+}
+
+// FILE: c.kt
+
+package a
+
+public fun X.gav(): Int {
+    if (x != null)
+        // Even if it's in the same package
+        return x<!UNSAFE_CALL!>.<!>length() 
+    else
+        return 0
+}

compiler/testData/diagnostics/tests/smartCasts/varnotnull/kt5907otherModule.txt

@@ -0,0 +1,29 @@
+// -- Module: <m1> --
+package
+
+package a {
+
+    public final class X {
+        public constructor X()
+        public final val x: kotlin.String? = null
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+}
+
+
+// -- Module: <m2> --
+package
+
+package a {
+    public fun a.X.gav(): kotlin.Int
+
+    public final class X {
+        // -- Module: <m1> --
+    }
+}
+
+package b {
+    public fun a.X.gav(): kotlin.Int
+}

compiler/testData/diagnostics/tests/smartCasts/varnotnull/kt5907protected.kt

@@ -0,0 +1,17 @@
+public open class X {
+    protected val x : String? = null
+    public fun fn(): Int {
+        if (x != null)
+            // Smartcast is possible for protected value property in the same class
+            return <!DEBUG_INFO_SMARTCAST!>x<!>.length()
+        else
+            return 0
+    }
+}
+
+public class Y: X() {
+    public fun bar(): Int {
+        // Smartcast is possible even in derived class
+        return if (x != null) <!DEBUG_INFO_SMARTCAST!>x<!>.length() else 0
+    }
+}

compiler/testData/diagnostics/tests/smartCasts/varnotnull/kt5907protected.txt

@@ -0,0 +1,20 @@
+package
+
+public open class X {
+    public constructor X()
+    protected final val x: kotlin.String? = null
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final fun fn(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class Y : X {
+    public constructor Y()
+    protected final override /*1*/ /*fake_override*/ val x: kotlin.String?
+    public final fun bar(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final override /*1*/ /*fake_override*/ fun fn(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/smartCasts/varnotnull/kt5907var.kt

@@ -0,0 +1,15 @@
+public class X {
+    public var x : String? = null
+    private var y: String? = "abc"
+    public fun fn(): Int {
+        if (x != null)
+            // Smartcast is not possible for variable properties
+            return x<!UNSAFE_CALL!>.<!>length()
+        else if (y != null)
+            // Even if they are private
+            return y<!UNSAFE_CALL!>.<!>length()
+        else
+            return 0
+    }
+}
+

compiler/testData/diagnostics/tests/smartCasts/varnotnull/kt5907var.txt

@@ -0,0 +1,11 @@
+package
+
+public final class X {
+    public constructor X()
+    public final var x: kotlin.String?
+    private final var y: kotlin.String?
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final fun fn(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}