Allow inferring property type from its getter

#KT-550 Fixed

compiler/testData/diagnostics/tests/RecursiveGetter.kt

@@ -1,3 +0,0 @@
-class A {
-    <!PROPERTY_WITH_NO_TYPE_NO_INITIALIZER!>val a<!> get() = <!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>a<!>
-}

compiler/testData/diagnostics/tests/declarationChecks/ambiguousObjectExpressionType.kt

@@ -24,7 +24,7 @@ class Foo {
 
     <!AMBIGUOUS_ANONYMOUS_TYPE_INFERRED!>public val <!EXPOSED_PROPERTY_TYPE!>publicProperty<!><!> = object : MyClass(), MyTrait {}
 
-    <!PROPERTY_WITH_NO_TYPE_NO_INITIALIZER!>val propertyWithGetter<!>
+    val <!EXPOSED_PROPERTY_TYPE!>propertyWithGetter<!>
         <!AMBIGUOUS_ANONYMOUS_TYPE_INFERRED!>get()<!> = object: MyClass(), MyTrait {}
 
 
@@ -117,4 +117,4 @@ fun fooPackage() {
     fun fooPackageLocal() = object : MyClass(), MyTrait {}
     fooPackageLocal().f1()
     fooPackageLocal().f2()
-}
+}

compiler/testData/diagnostics/tests/declarationChecks/ambiguousObjectExpressionType.txt

@@ -16,7 +16,7 @@ public final class Foo {
     internal final val internal2Property: Foo.internal2Property.<no name provided>
     public final val internalProperty: Foo.internalProperty.<no name provided>
     private final val privateProperty: Foo.privateProperty.<no name provided>
-    public final val propertyWithGetter: [ERROR : No type, no body]
+    public final val propertyWithGetter: Foo.<get-propertyWithGetter>.<no name provided>
     protected final val protectedProperty: Foo.protectedProperty.<no name provided>
     public final val publicProperty: Foo.publicProperty.<no name provided>
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean

compiler/testData/diagnostics/tests/properties/inferenceFromGetters/blockBodyGetter.kt

@@ -0,0 +1,3 @@
+<!PROPERTY_WITH_NO_TYPE_NO_INITIALIZER!>val x<!> get() {
+    return 1
+}

compiler/testData/diagnostics/tests/properties/inferenceFromGetters/blockBodyGetter.txt

@@ -0,0 +1,3 @@
+package
+
+public val x: [ERROR : No type, no body]

compiler/testData/diagnostics/tests/properties/inferenceFromGetters/cantBeInferred.kt

@@ -0,0 +1,5 @@
+val x get() = <!TYPE_INFERENCE_NO_INFORMATION_FOR_PARAMETER!>foo<!>()
+val y get() = <!TYPE_INFERENCE_NO_INFORMATION_FOR_PARAMETER!>bar<!>()
+
+fun <E> foo(): E = null!!
+fun <E> bar(): List<E> = null!!

compiler/testData/diagnostics/tests/properties/inferenceFromGetters/cantBeInferred.txt

@@ -0,0 +1,6 @@
+package
+
+public val x: [ERROR : Error function type]
+public val y: [ERROR : Error function type]
+public fun </*0*/ E> bar(): kotlin.collections.List<E>
+public fun </*0*/ E> foo(): E

compiler/testData/diagnostics/tests/properties/inferenceFromGetters/explicitGetterType.kt

@@ -0,0 +1,18 @@
+// !CHECK_TYPE
+val x get(): String = foo()
+val y get(): List<Int> = bar()
+val z get(): List<Int> {
+    return bar()
+}
+
+<!MUST_BE_INITIALIZED!>val u<!> get(): String = field
+
+fun <E> foo(): E = null!!
+fun <E> bar(): List<E> = null!!
+
+
+fun baz() {
+    x checkType { _<String>() }
+    y checkType { _<List<Int>>() }
+    z checkType { _<List<Int>>() }
+}

compiler/testData/diagnostics/tests/properties/inferenceFromGetters/explicitGetterType.txt

@@ -0,0 +1,9 @@
+package
+
+public val u: kotlin.String
+public val x: kotlin.String
+public val y: kotlin.collections.List<kotlin.Int>
+public val z: kotlin.collections.List<kotlin.Int>
+public fun </*0*/ E> bar(): kotlin.collections.List<E>
+public fun baz(): kotlin.Unit
+public fun </*0*/ E> foo(): E

compiler/testData/diagnostics/tests/properties/inferenceFromGetters/members.kt

@@ -0,0 +1,24 @@
+// !CHECK_TYPE
+class A {
+    val x get() = 1
+    val y get() = id(1)
+    val y2 get() = id(id(2))
+    val z get() = l("")
+    val z2 get() = l(id(l("")))
+
+    val <T> T.u get() = id(this)
+}
+fun <E> id(x: E) = x
+fun <E> l(<!UNUSED_PARAMETER!>x<!>: E): List<E> = null!!
+
+fun foo(a: A) {
+    a.x checkType { _<Int>() }
+    a.y checkType { _<Int>() }
+    a.y2 checkType { _<Int>() }
+    a.z checkType { _<List<String>>() }
+    a.z2 checkType { _<List<List<String>>>() }
+
+    with(a) {
+        1.u checkType { _<Int>() }
+    }
+}

compiler/testData/diagnostics/tests/properties/inferenceFromGetters/members.txt

@@ -0,0 +1,18 @@
+package
+
+public fun foo(/*0*/ a: A): kotlin.Unit
+public fun </*0*/ E> id(/*0*/ x: E): E
+public fun </*0*/ E> l(/*0*/ x: E): kotlin.collections.List<E>
+
+public final class A {
+    public constructor A()
+    public final val x: kotlin.Int
+    public final val y: kotlin.Int
+    public final val y2: kotlin.Int
+    public final val z: kotlin.collections.List<kotlin.String>
+    public final val z2: kotlin.collections.List<kotlin.collections.List<kotlin.String>>
+    public final val </*0*/ T> T.u: T
+    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/properties/inferenceFromGetters/nullAsNothing.kt

@@ -0,0 +1,8 @@
+// !CHECK_TYPE
+val x get() = null
+val <!IMPLICIT_NOTHING_PROPERTY_TYPE!>y<!> get() = null!!
+
+fun foo() {
+    <!DEBUG_INFO_CONSTANT!>x<!> checkType { _<Nothing?>() }
+    y <!UNREACHABLE_CODE!>checkType { _<Nothing>() }<!>
+}

compiler/testData/diagnostics/tests/properties/inferenceFromGetters/nullAsNothing.txt

@@ -0,0 +1,5 @@
+package
+
+public val x: kotlin.Nothing?
+public val y: kotlin.Nothing
+public fun foo(): kotlin.Unit

compiler/testData/diagnostics/tests/properties/inferenceFromGetters/objectExpression.kt

@@ -0,0 +1,35 @@
+// !CHECK_TYPE
+object Outer {
+    private var x
+        get() = object : CharSequence {
+            override val length: Int
+                get() = 0
+
+            override fun get(index: Int): Char {
+                checkSubtype<CharSequence>(<!TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM!>x<!>)
+                return ' '
+            }
+
+            override fun subSequence(startIndex: Int, endIndex: Int) = ""
+
+            fun bar() {
+            }
+        }
+        set(q) {
+            checkSubtype<CharSequence>(x)
+            y = q
+            x = q
+        }
+
+    private var y = <!DEBUG_INFO_LEAKING_THIS!>x<!>
+
+    fun foo() {
+        x = y
+
+        checkSubtype<CharSequence>(x)
+        checkSubtype<CharSequence>(y)
+
+        x.bar()
+        y.bar()
+    }
+}

compiler/testData/diagnostics/tests/properties/inferenceFromGetters/objectExpression.txt

@@ -1,9 +1,11 @@
 package
 
-public final class A {
-    public constructor A()
-    public final val a: [ERROR : No type, no body]
+public object Outer {
+    private constructor Outer()
+    private final var x: Outer.<get-x>.<no name provided>
+    private final var y: Outer.<get-x>.<no name provided>
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public final fun foo(): kotlin.Unit
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }

compiler/testData/diagnostics/tests/properties/inferenceFromGetters/overrides.kt

@@ -0,0 +1,41 @@
+// !CHECK_TYPE
+interface A {
+    val x: Int
+
+    val z: Comparable<*>
+}
+
+open class B {
+    open var y = ""
+
+    open val z: CharSequence = ""
+}
+
+class C : B(), A {
+    override val x
+        get() = 1
+
+    override var y
+        get() = super.y
+        set(value) {
+            value checkType { _<String>() }
+        }
+
+    override var z
+        get() = ""
+        set(value) {
+            value checkType { _<String>() }
+        }
+}
+
+fun foo(c: C) {
+    c.x checkType { _<Int>() }
+    c.y checkType { _<String>() }
+    c.z checkType { _<String>() }
+
+    c.y = ""
+    c.y = <!CONSTANT_EXPECTED_TYPE_MISMATCH!>1<!>
+
+    c.z = ""
+    c.z = <!CONSTANT_EXPECTED_TYPE_MISMATCH!>1<!>
+}

compiler/testData/diagnostics/tests/properties/inferenceFromGetters/overrides.txt

@@ -0,0 +1,30 @@
+package
+
+public fun foo(/*0*/ c: C): kotlin.Unit
+
+public interface A {
+    public abstract val x: kotlin.Int
+    public abstract val z: kotlin.Comparable<*>
+    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 open class B {
+    public constructor B()
+    public open var y: kotlin.String
+    public open val z: kotlin.CharSequence
+    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 C : B, A {
+    public constructor C()
+    public open override /*1*/ val x: kotlin.Int
+    public open override /*1*/ var y: kotlin.String
+    public open override /*2*/ var z: kotlin.String
+    public open override /*2*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*2*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*2*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/properties/inferenceFromGetters/recursiveGetter.kt

@@ -0,0 +1,18 @@
+// !CHECK_TYPE
+
+val x get() = <!TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM!>x<!>
+
+class A {
+    val y get() = <!TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM!>y<!>
+
+    val a get() = <!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>b<!>
+    val b get() = <!TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM!>a<!>
+
+    val z1 get() = id(<!TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM, DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>z1<!>)
+    val z2 get() = l(<!TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM, DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>z2<!>)
+
+    val u get() = <!UNRESOLVED_REFERENCE!>field<!>
+}
+
+fun <E> id(x: E) = x
+fun <E> l(<!UNUSED_PARAMETER!>x<!>: E): List<E> = null!!

compiler/testData/diagnostics/tests/properties/inferenceFromGetters/recursiveGetter.txt

@@ -0,0 +1,18 @@
+package
+
+public val x: [ERROR : Error function type]
+public fun </*0*/ E> id(/*0*/ x: E): E
+public fun </*0*/ E> l(/*0*/ x: E): kotlin.collections.List<E>
+
+public final class A {
+    public constructor A()
+    public final val a: [ERROR : Error function type]
+    public final val b: [ERROR : Error function type]
+    public final val u: [ERROR : Error function type]
+    public final val y: [ERROR : Error function type]
+    public final val z1: [ERROR : Error function type]
+    public final val z2: [ERROR : Error function type]
+    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/properties/inferenceFromGetters/topLevel.kt

@@ -0,0 +1,21 @@
+// !CHECK_TYPE
+val x get() = 1
+val y get() = id(1)
+val y2 get() = id(id(2))
+val z get() = l("")
+val z2 get() = l(id(l("")))
+
+val <T> T.u get() = id(this)
+
+fun <E> id(x: E) = x
+fun <E> l(<!UNUSED_PARAMETER!>x<!>: E): List<E> = null!!
+
+fun foo() {
+    x checkType { _<Int>() }
+    y checkType { _<Int>() }
+    y2 checkType { _<Int>() }
+    z checkType { _<List<String>>() }
+    z2 checkType { _<List<List<String>>>() }
+
+    1.u checkType { _<Int>() }
+}

compiler/testData/diagnostics/tests/properties/inferenceFromGetters/topLevel.txt

@@ -0,0 +1,11 @@
+package
+
+public val x: kotlin.Int
+public val y: kotlin.Int
+public val y2: kotlin.Int
+public val z: kotlin.collections.List<kotlin.String>
+public val z2: kotlin.collections.List<kotlin.collections.List<kotlin.String>>
+public val </*0*/ T> T.u: T
+public fun foo(): kotlin.Unit
+public fun </*0*/ E> id(/*0*/ x: E): E
+public fun </*0*/ E> l(/*0*/ x: E): kotlin.collections.List<E>

compiler/testData/diagnostics/tests/properties/inferenceFromGetters/vars.kt

@@ -0,0 +1,21 @@
+// !CHECK_TYPE
+var x
+    get() = 1
+    set(q) {
+        q checkType { _<Int>() }
+    }
+
+<!MUST_BE_INITIALIZED!>var noSetter<!>
+    get() = 1
+
+
+fun foo() {
+    x checkType { _<Int>() }
+    noSetter checkType { _<Int>() }
+
+    x = 1
+    x = <!TYPE_MISMATCH!>""<!>
+
+    noSetter = 2
+    noSetter = <!TYPE_MISMATCH!>""<!>
+}

compiler/testData/diagnostics/tests/properties/inferenceFromGetters/vars.txt

@@ -0,0 +1,5 @@
+package
+
+public var noSetter: kotlin.Int
+public var x: kotlin.Int
+public fun foo(): kotlin.Unit