Allow use contract function by FQN. #KT-29772 fixed

compiler/psi/src/org/jetbrains/kotlin/psi/psiUtil/ktPsiUtil.kt

@@ -308,7 +308,12 @@ fun KtNamedFunction.isContractPresentPsiCheck(): Boolean {
 }
 
 fun KtExpression.isContractDescriptionCallPsiCheck(): Boolean =
-    this is KtCallExpression && calleeExpression?.text == "contract"
+    (this is KtCallExpression && calleeExpression?.text == "contract") || (this is KtQualifiedExpression && isContractDescriptionCallPsiCheck())
+
+fun KtQualifiedExpression.isContractDescriptionCallPsiCheck(): Boolean {
+    val expression = selectorExpression ?: return false
+    return receiverExpression.text == "kotlin.contracts" && expression.isContractDescriptionCallPsiCheck()
+}
 
 
 // ----------- Other -----------------------------------------------------------------------------------------------------------------------

compiler/testData/diagnostics/testsWithStdLib/contracts/dsl/fqnContractFunction.kt

@@ -0,0 +1,20 @@
+// !LANGUAGE: +AllowContractsForCustomFunctions +UseReturnsEffect
+// !USE_EXPERIMENTAL: kotlin.contracts.ExperimentalContracts
+// !DIAGNOSTICS: -INVISIBLE_REFERENCE -INVISIBLE_MEMBER
+
+import kotlin.contracts.InvocationKind
+
+inline fun foo(block: () -> Unit) {
+    kotlin.contracts.contract {
+        callsInPlace(block, InvocationKind.EXACTLY_ONCE)
+    }
+    block()
+}
+
+fun main() {
+    val x: Int
+    foo {
+        x = 42
+    }
+    println(x)
+}

compiler/testData/diagnostics/testsWithStdLib/contracts/dsl/fqnContractFunction.txt

@@ -0,0 +1,6 @@
+package
+
+public inline fun foo(/*0*/ block: () -> kotlin.Unit): kotlin.Unit
+    CallsInPlace(block, EXACTLY_ONCE)
+
+public fun main(): kotlin.Unit

compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestWithStdLibGenerated.java

@@ -1137,6 +1137,11 @@ public class DiagnosticsTestWithStdLibGenerated extends AbstractDiagnosticsTestW
                 runTest("compiler/testData/diagnostics/testsWithStdLib/contracts/dsl/callUsualContractFunction.kt");
             }
 
+            @TestMetadata("fqnContractFunction.kt")
+            public void testFqnContractFunction() throws Exception {
+                runTest("compiler/testData/diagnostics/testsWithStdLib/contracts/dsl/fqnContractFunction.kt");
+            }
+
             @TestMetadata("rewriteAtSliceFunctor.kt")
             public void testRewriteAtSliceFunctor() throws Exception {
                 runTest("compiler/testData/diagnostics/testsWithStdLib/contracts/dsl/rewriteAtSliceFunctor.kt");

compiler/tests/org/jetbrains/kotlin/checkers/javac/DiagnosticsTestWithStdLibUsingJavacGenerated.java

@@ -1137,6 +1137,11 @@ public class DiagnosticsTestWithStdLibUsingJavacGenerated extends AbstractDiagno
                 runTest("compiler/testData/diagnostics/testsWithStdLib/contracts/dsl/callUsualContractFunction.kt");
             }
 
+            @TestMetadata("fqnContractFunction.kt")
+            public void testFqnContractFunction() throws Exception {
+                runTest("compiler/testData/diagnostics/testsWithStdLib/contracts/dsl/fqnContractFunction.kt");
+            }
+
             @TestMetadata("rewriteAtSliceFunctor.kt")
             public void testRewriteAtSliceFunctor() throws Exception {
                 runTest("compiler/testData/diagnostics/testsWithStdLib/contracts/dsl/rewriteAtSliceFunctor.kt");