[FIR] Report missing ASSIGNMENT_TYPE_MISMATCH on functional types

^KT-45989

compiler/testData/diagnostics/tests/inference/completion/postponedArgumentsAnalysis/basic.fir.kt

@@ -153,7 +153,7 @@ fun main() {
     // Convert to extension lambda is impossible because the lambda parameter types aren't specified explicitly
     select(id(fun String.(x: String) {}), id(fun(x: String, y: String) { }), <!ARGUMENT_TYPE_MISMATCH!>{ x, <!CANNOT_INFER_PARAMETER_TYPE!>y<!> -> x }<!>)
     select(id(id(fun(x: String, y: String) { }), <!TOO_MANY_ARGUMENTS!>fun String.(x: String) {}<!>), { x, y -> x })
-    val x26: Int.(String) -> Int = fun (x: String) = 10 // it must be error, see KT-38439
+    val x26: Int.(String) -> Int = <!INITIALIZER_TYPE_MISMATCH!>fun (x: String) = 10<!> // it must be error, see KT-38439
     // Receiver must be specified in anonymous function declaration
     val x27: Int.(String) -> Int = id(<!ARGUMENT_TYPE_MISMATCH, ARGUMENT_TYPE_MISMATCH!>fun (x: String) = 10<!>)
     select(id<Int.(String) -> Unit> {}, { x: Int, y: String -> x })

compiler/testData/diagnostics/tests/inference/lambdaInValInitializerWithAnonymousFunctions.fir.kt

@@ -5,5 +5,5 @@ val test2f: suspend Any.() -> Unit = fun Any.() {}
 
 // This is a bug in the old inference and should be fixed in new inference
 // see "Fix anonymous function literals handling in type checker" for more details
-val test3f: suspend Any.(Int) -> Int = fun (k: Int) = k + 1
-val test4f: SuspendFn = fun Any.() {}
+val test3f: suspend Any.(Int) -> Int = <!INITIALIZER_TYPE_MISMATCH!>fun (k: Int) = k + 1<!>
+val test4f: SuspendFn = <!INITIALIZER_TYPE_MISMATCH!>fun Any.() {}<!>