[FIR] Unwrap blocks in the list of return expression of lambdas

If lambda contains destructuring parameters we generate the body of lambda
  in the separate block as the last statement of lambda body. This block
  should not be considered as actual return expression of the lambda

^KT-67185 Fixed

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/ControlFlowGraphBuilder.kt

@@ -101,7 +101,7 @@ class ControlFlowGraphBuilder {
                 // lambda@{ x } -> x
                 // lambda@{ class C } -> Unit-returning stub
                 function.isLambda -> {
-                    val lastStatement = fir.statements.lastOrNull()
+                    val lastStatement = function.lastStatement()
 
                     when {
                         // Skip last return statement because otherwise it add Nothing constraint on the lambda return type.
@@ -1619,3 +1619,18 @@ val FirControlFlowGraphOwner.isUsedInControlFlowGraphBuilderForScript: Boolean
 @OptIn(UnresolvedExpressionTypeAccess::class)
 private val FirExpression.hasNothingType: Boolean
     get() = coneTypeOrNull?.isNothing == true
+
+fun FirAnonymousFunction.lastStatement(): FirStatement? {
+    val last = this.body?.statements?.lastOrNull() ?: return null
+
+    fun FirStatement.unwrapBlocks(): FirStatement {
+        return when (this) {
+            is FirBlock -> statements.lastOrNull()?.unwrapBlocks() ?: this
+            else -> this
+        }
+    }
+
+    return last.unwrapBlocks()
+}
+
+

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/PostponedArgumentsAnalyzer.kt

@@ -11,6 +11,7 @@ import org.jetbrains.kotlin.fir.lookupTracker
 import org.jetbrains.kotlin.fir.recordTypeResolveAsLookup
 import org.jetbrains.kotlin.fir.references.builder.buildErrorNamedReference
 import org.jetbrains.kotlin.fir.resolve.calls.*
+import org.jetbrains.kotlin.fir.resolve.dfa.cfg.lastStatement
 import org.jetbrains.kotlin.fir.resolve.diagnostics.ConeUnresolvedReferenceError
 import org.jetbrains.kotlin.fir.resolve.inference.model.ConeLambdaArgumentConstraintPosition
 import org.jetbrains.kotlin.fir.resolve.shouldReturnUnit
@@ -180,7 +181,7 @@ class PostponedArgumentsAnalyzer(
         val checkerSink: CheckerSink = CheckerSinkImpl(candidate)
         val builder = c.getBuilder()
 
-        val lastExpression = lambda.atom.body?.statements?.lastOrNull() as? FirExpression
+        val lastExpression = lambda.atom.lastStatement() as? FirExpression
         var hasExpressionInReturnArguments = false
         val returnTypeRef = lambda.atom.returnTypeRef.let {
             it as? FirResolvedTypeRef ?: it.resolvedTypeFromPrototype(substitute(lambda.returnType))

compiler/testData/codegen/box/destructuringDeclInLambdaParam/lambdaInLambda.kt

@@ -0,0 +1,15 @@
+// ISSUE: KT-67185
+// WITH_STDLIB
+
+fun noop() {}
+
+fun foo(list: List<Pair<String, String>>) {
+    list.map { (a, b) -> { noop() } }
+        .forEach { it() }
+}
+
+fun box(): String {
+    val list = listOf("a" to "b", "c" to "")
+    foo(list)
+    return "OK"
+}