Support contracts in PartialBodyResolveFilter

Previously, PartialBodyResolveFilter didn't know about contracts and was
filtering out calls of such functions, leading to unstable completion in
cases like that:

fun test(x: Any?) {
    require(x is String)
    x.<caret>
}

However, PartialBodyResolveFilter works by pure PSI, while to determine
if function has a contract we have to resolve it.

To solve it, we do something very similar to what has been done with
Nothin-returning functions: introduce
KotlinProbablyContractedFunctionShortNameIndex, which collects all
function which *may* have a contract during indexing.

^KT-25275 Fixed

idea/testData/resolve/partialBodyResolve/ContractFromBinary.completion

@@ -0,0 +1,17 @@
+Resolve target: value-parameter x: kotlin.Any? smart-cast to kotlin.String
+----------------------------------------------
+// COMPILER_ARGUMENTS: -XXLanguage:+ReadDeserializedContracts -XXLanguage:+UseReturnsEffect
+package test
+
+fun irrelevantConsume(y: Any?) {}
+
+fun testContractFromBinaryDependency(x: Any?, y: Any?) {
+    require(x is String)
+
+    require(y is String)
+    /* STATEMENT DELETED: irrelevantConsume(x) */
+
+    <caret>x.length
+
+    /* STATEMENT DELETED: require(x is Int) */
+}

idea/testData/resolve/partialBodyResolve/ContractFromBinary.dump

@@ -0,0 +1,17 @@
+Resolve target: value-parameter x: kotlin.Any? smart-cast to kotlin.String
+----------------------------------------------
+// COMPILER_ARGUMENTS: -XXLanguage:+ReadDeserializedContracts -XXLanguage:+UseReturnsEffect
+package test
+
+fun irrelevantConsume(y: Any?) {}
+
+fun testContractFromBinaryDependency(x: Any?, y: Any?) {
+    require(x is String)
+
+    /* STATEMENT DELETED: require(y is String) */
+    /* STATEMENT DELETED: irrelevantConsume(x) */
+
+    <caret>x.length
+
+    /* STATEMENT DELETED: require(x is Int) */
+}

idea/testData/resolve/partialBodyResolve/ContractFromBinary.kt

@@ -0,0 +1,15 @@
+// COMPILER_ARGUMENTS: -XXLanguage:+ReadDeserializedContracts -XXLanguage:+UseReturnsEffect
+package test
+
+fun irrelevantConsume(y: Any?) {}
+
+fun testContractFromBinaryDependency(x: Any?, y: Any?) {
+    require(x is String)
+
+    require(y is String)
+    irrelevantConsume(x)
+
+    <caret>x.length
+
+    require(x is Int)
+}

idea/testData/resolve/partialBodyResolve/ContractFromSource.completion

@@ -0,0 +1,22 @@
+Resolve target: value-parameter x: kotlin.Any? smart-cast to kotlin.String
+----------------------------------------------
+// COMPILER_ARGUMENTS: -XXLanguage:+AllowContractsForCustomFunctions -XXLanguage:+UseReturnsEffect
+@file:Suppress("INVISIBLE_MEMBER")
+package test
+
+import kotlin.internal.contracts.*
+
+fun myRequire(x: Boolean) {
+    contract {
+        returns() implies x
+    }
+}
+
+fun testContractFromSource(x: Any?, y: Any?) {
+    myRequire(x is String)
+    myRequire(y is String)
+
+    <caret>x.length
+
+    /* STATEMENT DELETED: myRequire(x is Int) */
+}

idea/testData/resolve/partialBodyResolve/ContractFromSource.dump

@@ -0,0 +1,22 @@
+Resolve target: value-parameter x: kotlin.Any? smart-cast to kotlin.String
+----------------------------------------------
+// COMPILER_ARGUMENTS: -XXLanguage:+AllowContractsForCustomFunctions -XXLanguage:+UseReturnsEffect
+@file:Suppress("INVISIBLE_MEMBER")
+package test
+
+import kotlin.internal.contracts.*
+
+fun myRequire(x: Boolean) {
+    contract {
+        returns() implies x
+    }
+}
+
+fun testContractFromSource(x: Any?, y: Any?) {
+    myRequire(x is String)
+    /* STATEMENT DELETED: myRequire(y is String) */
+
+    <caret>x.length
+
+    /* STATEMENT DELETED: myRequire(x is Int) */
+}

idea/testData/resolve/partialBodyResolve/ContractFromSource.kt

@@ -0,0 +1,20 @@
+// COMPILER_ARGUMENTS: -XXLanguage:+AllowContractsForCustomFunctions -XXLanguage:+UseReturnsEffect
+@file:Suppress("INVISIBLE_MEMBER")
+package test
+
+import kotlin.internal.contracts.*
+
+fun myRequire(x: Boolean) {
+    contract {
+        returns() implies x
+    }
+}
+
+fun testContractFromSource(x: Any?, y: Any?) {
+    myRequire(x is String)
+    myRequire(y is String)
+
+    <caret>x.length
+
+    myRequire(x is Int)
+}

idea/testData/resolve/partialBodyResolve/DeclarationsBefore.completion

@@ -9,7 +9,10 @@ fun foo(p: Int) {
         val v2 = v1 * v1
         val v3 = v1 * v2
 
-        /* STATEMENT DELETED: run { val v2 = 1 println(v2) } */
+        run {
+            val v2 = 1
+            println(v2)
+        }
 
         print(<caret>v2)
 

idea/testData/resolve/partialBodyResolve/DeclarationsBefore.dump

@@ -9,7 +9,10 @@ fun foo(p: Int) {
         val v2 = v1 * v1
         /* STATEMENT DELETED: val v3 = v1 * v2 */
 
-        /* STATEMENT DELETED: run { val v2 = 1 println(v2) } */
+        run {
+            val v2 = 1
+            println(v2)
+        }
 
         print(<caret>v2)