Add few tests for contracts

- Contracts in getter/setter (unexpected behaviour)
- Check smartcasts when non-null assertion for a contract function is used
- Check work of contracts when type parameter of the callsInPlace is specify explicitly
- Check smartcasts working if type checking for contract function is used

compiler/tests-spec/testData/diagnostics/notLinked/contracts/analysis/smartcasts/neg/15.kt

@@ -0,0 +1,58 @@
+// !LANGUAGE: +AllowContractsForCustomFunctions +UseReturnsEffect
+// !WITH_CONTRACT_FUNCTIONS
+// !DIAGNOSTICS: -INVISIBLE_REFERENCE -INVISIBLE_MEMBER
+// !USE_EXPERIMENTAL: kotlin.contracts.ExperimentalContracts
+
+/*
+ KOTLIN DIAGNOSTICS NOT LINKED SPEC TEST (NEGATIVE)
+
+ SECTION: contracts
+ CATEGORIES: analysis, smartcasts
+ NUMBER: 15
+ DESCRIPTION: Check smartcasts working if type checking for contract function is used
+ UNEXPECTED BEHAVIOUR
+ ISSUES: KT-27241
+ */
+
+// FILE: contracts.kt
+
+package contracts
+
+import kotlin.contracts.*
+
+fun case_1_1(cond: Boolean): Any {
+    contract { returns(true) implies cond }
+    return cond
+}
+
+fun case_1_2(value: Any): Boolean {
+    contract { returns(true) implies (value is Boolean) }
+    return value is Boolean
+}
+
+fun case_2(cond: Boolean): Any {
+    contract { returns(true) implies cond }
+    return cond
+}
+
+// FILE: usages.kt
+
+import contracts.*
+
+fun case_1(value: Any) {
+    if (contracts.case_1_2(contracts.case_1_1(value is Char))) {
+        println(<!DEBUG_INFO_SMARTCAST!>value<!>.category)
+    }
+}
+
+fun case_2(value: Any) {
+    if (contracts.case_2(value is Char) is Boolean) {
+        println(<!DEBUG_INFO_SMARTCAST!>value<!>.category)
+    }
+}
+
+fun case_3(value: String?) {
+    if (<!USELESS_IS_CHECK!>!value.isNullOrEmpty() is Boolean<!>) {
+        <!DEBUG_INFO_SMARTCAST!>value<!>.length
+    }
+}

compiler/tests-spec/testData/diagnostics/notLinked/contracts/analysis/smartcasts/neg/15.txt

@@ -0,0 +1,124 @@
+package
+
+public fun case_1(/*0*/ value: kotlin.Any): kotlin.Unit
+public fun case_2(/*0*/ value: kotlin.Any): kotlin.Unit
+public fun case_3(/*0*/ value: kotlin.String?): kotlin.Unit
+public inline fun </*0*/ T> funWithAtLeastOnceCallsInPlace(/*0*/ block: () -> T): T
+    CallsInPlace(block, AT_LEAST_ONCE)
+
+public inline fun funWithAtLeastOnceCallsInPlace(/*0*/ block: () -> kotlin.Unit): kotlin.Unit
+    CallsInPlace(block, AT_LEAST_ONCE)
+
+public inline fun funWithAtMostOnceCallsInPlace(/*0*/ block: () -> kotlin.Unit): kotlin.Unit
+    CallsInPlace(block, AT_MOST_ONCE)
+
+public inline fun </*0*/ T> funWithExactlyOnceCallsInPlace(/*0*/ block: () -> T): T
+    CallsInPlace(block, EXACTLY_ONCE)
+
+public inline fun funWithExactlyOnceCallsInPlace(/*0*/ block: () -> kotlin.Unit): kotlin.Unit
+    CallsInPlace(block, EXACTLY_ONCE)
+
+public fun funWithReturns(/*0*/ cond: kotlin.Boolean): kotlin.Unit
+    Returns(WILDCARD) -> cond
+
+public fun funWithReturnsAndInvertCondition(/*0*/ cond: kotlin.Boolean): kotlin.Unit
+    Returns(WILDCARD) -> !cond
+
+public fun funWithReturnsAndInvertTypeCheck(/*0*/ value_1: kotlin.Any?): kotlin.Unit
+    Returns(WILDCARD) -> value_1 !is String
+
+public fun funWithReturnsAndNotNullCheck(/*0*/ value_1: kotlin.Any?): kotlin.Unit
+    Returns(WILDCARD) -> value_1 != null
+
+public fun funWithReturnsAndNullCheck(/*0*/ value_1: kotlin.Any?): kotlin.Unit
+    Returns(WILDCARD) -> value_1 == null
+
+public fun funWithReturnsAndTypeCheck(/*0*/ value_1: kotlin.Any?): kotlin.Unit
+    Returns(WILDCARD) -> value_1 is String
+
+public fun funWithReturnsFalse(/*0*/ cond: kotlin.Boolean): kotlin.Boolean
+    Returns(FALSE) -> cond
+
+public fun funWithReturnsFalseAndInvertCondition(/*0*/ cond: kotlin.Boolean): kotlin.Boolean
+    Returns(FALSE) -> !cond
+
+public fun funWithReturnsFalseAndInvertTypeCheck(/*0*/ value_1: kotlin.Any?): kotlin.Boolean
+    Returns(FALSE) -> value_1 !is String
+
+public fun funWithReturnsFalseAndNotNullCheck(/*0*/ value_1: kotlin.Number?): kotlin.Boolean
+    Returns(FALSE) -> value_1 != null
+
+public fun funWithReturnsFalseAndNullCheck(/*0*/ value_1: kotlin.Number?): kotlin.Boolean
+    Returns(FALSE) -> value_1 == null
+
+public fun funWithReturnsFalseAndTypeCheck(/*0*/ value_1: kotlin.Any?): kotlin.Boolean
+    Returns(FALSE) -> value_1 is String
+
+public fun funWithReturnsNotNull(/*0*/ cond: kotlin.Boolean): kotlin.Boolean?
+    Returns(NOT_NULL) -> cond
+
+public fun funWithReturnsNotNullAndInvertCondition(/*0*/ cond: kotlin.Boolean): kotlin.Boolean?
+    Returns(NOT_NULL) -> !cond
+
+public fun funWithReturnsNotNullAndInvertTypeCheck(/*0*/ value_1: kotlin.Any?): kotlin.Boolean?
+    Returns(NOT_NULL) -> value_1 !is String
+
+public fun funWithReturnsNotNullAndNotNullCheck(/*0*/ value_1: kotlin.Number?): kotlin.Boolean?
+    Returns(NOT_NULL) -> value_1 != null
+
+public fun funWithReturnsNotNullAndNullCheck(/*0*/ value_1: kotlin.Number?): kotlin.Boolean?
+    Returns(NOT_NULL) -> value_1 == null
+
+public fun funWithReturnsNotNullAndTypeCheck(/*0*/ value_1: kotlin.Any?): kotlin.Boolean?
+    Returns(NOT_NULL) -> value_1 is String
+
+public fun funWithReturnsNull(/*0*/ cond: kotlin.Boolean): kotlin.Boolean?
+    Returns(NULL) -> cond
+
+public fun funWithReturnsNullAndInvertCondition(/*0*/ cond: kotlin.Boolean): kotlin.Boolean?
+    Returns(NULL) -> !cond
+
+public fun funWithReturnsNullAndInvertTypeCheck(/*0*/ value_1: kotlin.Any?): kotlin.Boolean?
+    Returns(NULL) -> value_1 !is String
+
+public fun funWithReturnsNullAndNotNullCheck(/*0*/ value_1: kotlin.Number?): kotlin.Boolean?
+    Returns(NULL) -> value_1 != null
+
+public fun funWithReturnsNullAndNullCheck(/*0*/ value_1: kotlin.Number?): kotlin.Boolean?
+    Returns(NULL) -> value_1 == null
+
+public fun funWithReturnsNullAndTypeCheck(/*0*/ value_1: kotlin.Any?): kotlin.Boolean?
+    Returns(NULL) -> value_1 is String
+
+public fun funWithReturnsTrue(/*0*/ cond: kotlin.Boolean): kotlin.Boolean
+    Returns(TRUE) -> cond
+
+public fun funWithReturnsTrueAndInvertCondition(/*0*/ cond: kotlin.Boolean): kotlin.Boolean
+    Returns(TRUE) -> !cond
+
+public fun funWithReturnsTrueAndInvertTypeCheck(/*0*/ value_1: kotlin.Any?): kotlin.Boolean
+    Returns(TRUE) -> value_1 !is String
+
+public fun funWithReturnsTrueAndNotNullCheck(/*0*/ value_1: kotlin.Any?): kotlin.Boolean
+    Returns(TRUE) -> value_1 != null
+
+public fun funWithReturnsTrueAndNullCheck(/*0*/ value_1: kotlin.Any?): kotlin.Boolean
+    Returns(TRUE) -> value_1 == null
+
+public fun funWithReturnsTrueAndTypeCheck(/*0*/ value_1: kotlin.Any?): kotlin.Boolean
+    Returns(TRUE) -> value_1 is String
+
+public inline fun funWithUnknownCallsInPlace(/*0*/ block: () -> kotlin.Unit): kotlin.Unit
+    CallsInPlace(block, UNKNOWN)
+
+package contracts {
+    public fun case_1_1(/*0*/ cond: kotlin.Boolean): kotlin.Any
+        Returns(TRUE) -> cond
+
+    public fun case_1_2(/*0*/ value: kotlin.Any): kotlin.Boolean
+        Returns(TRUE) -> value is Boolean
+
+    public fun case_2(/*0*/ cond: kotlin.Boolean): kotlin.Any
+        Returns(TRUE) -> cond
+
+}

compiler/tests-spec/testData/diagnostics/notLinked/contracts/analysis/smartcasts/pos/14.kt

@@ -0,0 +1,80 @@
+// !LANGUAGE: +AllowContractsForCustomFunctions +UseCallsInPlaceEffect
+// !DIAGNOSTICS: -INVISIBLE_REFERENCE -INVISIBLE_MEMBER
+// !USE_EXPERIMENTAL: kotlin.contracts.ExperimentalContracts
+
+/*
+ KOTLIN DIAGNOSTICS NOT LINKED SPEC TEST (POSITIVE)
+
+ SECTION: contracts
+ CATEGORIES: analysis, smartcasts
+ NUMBER: 14
+ DESCRIPTION: Check smartcast with non-null assertion for a contract function.
+ UNEXPECTED BEHAVIOUR
+ ISSUES: KT-26856
+ */
+
+// FILE: contracts.kt
+
+package contracts
+
+import kotlin.contracts.*
+
+fun case_1(value_1: Int?): Boolean? {
+    contract {
+        returns(true) implies (value_1 != null)
+    }
+
+    return value_1 != null
+}
+
+fun case_2(value_1: Int?): Boolean {
+    contract {
+        returns(false) implies (value_1 != null)
+    }
+
+    return value_1 != null
+}
+
+fun case_3(value_1: Int?): Boolean? {
+    contract {
+        returnsNotNull() implies (value_1 != null)
+    }
+
+    return value_1 != null
+}
+
+fun case_4(value_1: Any?): Boolean {
+    contract {
+        returnsNotNull() implies (value_1 is Number)
+    }
+
+    return value_1 is Number
+}
+
+// FILE: usages.kt
+
+import contracts.*
+
+fun case_1(value_1: Int?) {
+    if (contracts.case_1(value_1)!!) {
+        value_1<!UNSAFE_CALL!>.<!>inv()
+    }
+}
+
+fun case_2(value_1: Int?) {
+    if (!contracts.case_2(value_1)<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>) {
+        value_1<!UNSAFE_CALL!>.<!>inv()
+    }
+}
+
+fun case_3(value_1: Int?) {
+    if (contracts.case_3(value_1)!!) {
+        value_1<!UNSAFE_CALL!>.<!>inv()
+    }
+}
+
+fun case_4(value_1: Any?) {
+    if (<!SENSELESS_COMPARISON!>contracts.case_4(value_1) != null<!>) {
+        <!DEBUG_INFO_SMARTCAST!>value_1<!>.toByte()
+    }
+}

compiler/tests-spec/testData/diagnostics/notLinked/contracts/analysis/smartcasts/pos/14.txt

@@ -0,0 +1,21 @@
+package
+
+public fun case_1(/*0*/ value_1: kotlin.Int?): kotlin.Unit
+public fun case_2(/*0*/ value_1: kotlin.Int?): kotlin.Unit
+public fun case_3(/*0*/ value_1: kotlin.Int?): kotlin.Unit
+public fun case_4(/*0*/ value_1: kotlin.Any?): kotlin.Unit
+
+package contracts {
+    public fun case_1(/*0*/ value_1: kotlin.Int?): kotlin.Boolean?
+        Returns(TRUE) -> value_1 != null
+
+    public fun case_2(/*0*/ value_1: kotlin.Int?): kotlin.Boolean
+        Returns(FALSE) -> value_1 != null
+
+    public fun case_3(/*0*/ value_1: kotlin.Int?): kotlin.Boolean?
+        Returns(NOT_NULL) -> value_1 != null
+
+    public fun case_4(/*0*/ value_1: kotlin.Any?): kotlin.Boolean
+        Returns(NOT_NULL) -> value_1 is Number
+
+}