diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/InferenceUtils.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/InferenceUtils.kt
index 51eac6a7ef4..bff94a0be79 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/InferenceUtils.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/InferenceUtils.kt
@@ -252,7 +252,6 @@ fun extractLambdaInfoFromFunctionalType(
}
if (!expectedType.isBuiltinFunctionalType(session)) return null
- val receiverType = argument.receiverType ?: expectedType.receiverType(session)
val lastStatement = argument.body?.statements?.singleOrNull()
val returnType =
// Simply { }, i.e., function literals without body. Raw FIR added an implicit return with an implicit unit type ref.
@@ -262,14 +261,16 @@ fun extractLambdaInfoFromFunctionalType(
session.builtinTypes.unitType.type
else
argument.returnType ?: expectedType.returnType(session)
+ // `fun (x: T) = ...` and `fun T.() = ...` are both instances of `T.() -> V`; `fun () = ...` is not.
+ // For lambdas, the existence of the receiver is always implied by the expected type, and a value parameter
+ // can never fill its role.
+ val receiverType = if (argument.isLambda) expectedType.receiverType(session) else argument.receiverType
val expectedParameters = expectedType.valueParameterTypesIncludingReceiver(session).let {
- if (expectedType.isExtensionFunctionType(session)) it.drop(1) else it
+ if (receiverType != null && expectedType.isExtensionFunctionType(session)) it.drop(1) else it
}
- val parameters = if (argument.valueParameters.isEmpty()) {
- expectedParameters
+ val parameters = if (argument.isLambda && argument.valueParameters.isEmpty() && expectedParameters.size < 2) {
+ expectedParameters // Infer existence of a parameter named `it` of an appropriate type.
} else {
- // TODO: `(A) -> B` is permitted as `A.() -> B` if it's an anonymous function, not a lambda;
- // e.g. `fun (x: Any?) = x` can be used as `Any?.() -> Any?`, but `{ it -> it }` cannot.
argument.valueParameters.mapIndexed { index, parameter ->
parameter.returnTypeRef.coneTypeSafe() ?: expectedParameters.getOrNull(index) ?: session.builtinTypes.nothingType.type
}
diff --git a/compiler/testData/diagnostics/tests/AutoCreatedIt.fir.kt b/compiler/testData/diagnostics/tests/AutoCreatedIt.fir.kt
index 4dd88964faa..b171ef0b6ea 100644
--- a/compiler/testData/diagnostics/tests/AutoCreatedIt.fir.kt
+++ b/compiler/testData/diagnostics/tests/AutoCreatedIt.fir.kt
@@ -3,8 +3,8 @@ fun text() {
"direct:a" to "mock:a"
"direct:a" on {it.body == ""} to "mock:a"
"direct:a" on {it -> it.body == ""} to "mock:a"
- bar {1}
- bar {it + 1}
+ bar {1}
+ bar {it + 1}
bar {it, it1 -> it}
bar1 {1}
diff --git a/compiler/testData/diagnostics/tests/functionAsExpression/ReceiverByExpectedType.fir.kt b/compiler/testData/diagnostics/tests/functionAsExpression/ReceiverByExpectedType.fir.kt
index a4249156f1e..ed8693f6b60 100644
--- a/compiler/testData/diagnostics/tests/functionAsExpression/ReceiverByExpectedType.fir.kt
+++ b/compiler/testData/diagnostics/tests/functionAsExpression/ReceiverByExpectedType.fir.kt
@@ -1,3 +1,3 @@
// !WITH_NEW_INFERENCE
fun foo(f: String.() -> Int) {}
-val test = foo(fun () = length)
+val test = foo(fun () = length)
diff --git a/compiler/testData/diagnostics/tests/functionLiterals/ExpectedParametersTypesMismatch.fir.kt b/compiler/testData/diagnostics/tests/functionLiterals/ExpectedParametersTypesMismatch.fir.kt
index f026618df0f..c9ef4f81daf 100644
--- a/compiler/testData/diagnostics/tests/functionLiterals/ExpectedParametersTypesMismatch.fir.kt
+++ b/compiler/testData/diagnostics/tests/functionLiterals/ExpectedParametersTypesMismatch.fir.kt
@@ -31,7 +31,7 @@ fun test1() {
foo2 {
- ""
+ ""
}
foo2 {
s: String -> ""
@@ -40,6 +40,6 @@ fun test1() {
x -> ""
}
foo2 {
- -> 42
+ -> 42
}
}
diff --git a/compiler/testData/diagnostics/tests/inference/completion/anonymousFunction.fir.kt b/compiler/testData/diagnostics/tests/inference/completion/anonymousFunction.fir.kt
index dc35cde2de0..6eb49eb6ef7 100644
--- a/compiler/testData/diagnostics/tests/inference/completion/anonymousFunction.fir.kt
+++ b/compiler/testData/diagnostics/tests/inference/completion/anonymousFunction.fir.kt
@@ -20,5 +20,5 @@ fun testFunctions() {
fun testNestedCalls() {
id(inferFromLambda { materialize() })
id(inferFromLambda(fun() = materialize()))
- id(inferFromLambda2(fun() = materialize()))
+ id(inferFromLambda2(fun() = materialize()))
}
diff --git a/compiler/testData/diagnostics/tests/inference/completion/postponedArgumentsAnalysis/basic.fir.kt b/compiler/testData/diagnostics/tests/inference/completion/postponedArgumentsAnalysis/basic.fir.kt
index 480bdc24d4b..87bdcc67010 100644
--- a/compiler/testData/diagnostics/tests/inference/completion/postponedArgumentsAnalysis/basic.fir.kt
+++ b/compiler/testData/diagnostics/tests/inference/completion/postponedArgumentsAnalysis/basic.fir.kt
@@ -228,7 +228,7 @@ fun main() {
val x70: (Int) -> Unit = selectNumber(id(fun (it) { }), id {}, id {})
val x71: String.() -> Unit = select(")!>id(fun String.() { }), ")!>id(fun(x: String) {}))
val x72: String.() -> Unit = select(fun String.() { }, fun(x: String) {}) // must be error
- select(id(fun String.(x: String) {}), id(fun(x: String, y: String) { }), fun (x, y) { x;y })
+ select(id(fun String.(x: String) {}), id(fun(x: String, y: String) { }), fun (x, y) { x;y })
select(id Unit>(fun (x, y) {}), { x: Int, y: String -> x }) // receiver of anonymous function must be specified explicitly
select(id Unit>(fun Int.(y) {}), { x: Int, y: String -> x })
")!>select(A3(), fun (x) = "", { a -> a })
diff --git a/compiler/testData/diagnostics/tests/regressions/kt30245.fir.kt b/compiler/testData/diagnostics/tests/regressions/kt30245.fir.kt
index 7af615291cb..8b844f809cd 100644
--- a/compiler/testData/diagnostics/tests/regressions/kt30245.fir.kt
+++ b/compiler/testData/diagnostics/tests/regressions/kt30245.fir.kt
@@ -111,7 +111,7 @@ fun test3() { // to non-extension lambda 1
// val i32: L1 = id { this } // this or it: oi- ni-
// val j32 = id { this } // this or it: oi- ni-
- val w33 = W3(fun Int.(): Int = this) // oi- ni+
+ val w33 = W3(fun Int.(): Int = this) // oi- ni+
val i33: L1 = id(fun Int.(): Int = this) // oi+ ni+
// yet unsupported cases with ambiguity for the lambda conversion (commented constructors in wrappers above)