Fix reading property function types

[ZacSweers]

Resolves #1265. This also moves @Suppress to be a file:-level suppression due to the kotlin.functions.* imports. We support simple function types as well as FunctionN types for functions with 23+ parameters.

Now for this snippet

@JsonClass(generateAdapter = true)
data class LambdaTypeName(
  val id: String,
  @Transient
  val custom: ((String) -> Boolean)? = null
)

We generate this:

// Code generated by moshi-kotlin-codegen. Do not edit.
@file:Suppress("DEPRECATION", "unused", "ClassName", "REDUNDANT_PROJECTION",
    "RedundantExplicitType", "LocalVariableName", "RedundantVisibilityModifier",
    "PLATFORM_CLASS_MAPPED_TO_KOTLIN")

package com.squareup.moshi.kotlin.codegen

import com.squareup.moshi.JsonAdapter
import com.squareup.moshi.JsonReader
import com.squareup.moshi.JsonWriter
import com.squareup.moshi.Moshi
import com.squareup.moshi.`internal`.Util
import java.lang.NullPointerException
import java.lang.reflect.Constructor
import kotlin.Int
import kotlin.String
import kotlin.Suppress
import kotlin.Unit
import kotlin.collections.emptySet
import kotlin.jvm.Volatile
import kotlin.jvm.functions.Function1
import kotlin.text.buildString

public class LambdaTypeNameJsonAdapter(
  moshi: Moshi
) : JsonAdapter<LambdaTypeName>() {
  private val options: JsonReader.Options = JsonReader.Options.of("id")

  private val stringAdapter: JsonAdapter<String> = moshi.adapter(String::class.java, emptySet(),
      "id")

  @Volatile
  private var constructorRef: Constructor<LambdaTypeName>? = null

  public override fun toString(): String = buildString(36) {
      append("GeneratedJsonAdapter(").append("LambdaTypeName").append(')') }

  public override fun fromJson(reader: JsonReader): LambdaTypeName {
    var id: String? = null
    var mask0 = -1
    reader.beginObject()
    while (reader.hasNext()) {
      when (reader.selectName(options)) {
        0 -> id = stringAdapter.fromJson(reader) ?: throw Util.unexpectedNull("id", "id", reader)
        -1 -> {
          // Unknown name, skip it.
          reader.skipName()
          reader.skipValue()
        }
      }
    }
    reader.endObject()
    @Suppress("UNCHECKED_CAST")
    val localConstructor: Constructor<LambdaTypeName> = this.constructorRef ?:
        LambdaTypeName::class.java.getDeclaredConstructor(String::class.java, Function1::class.java,
        Int::class.javaPrimitiveType, Util.DEFAULT_CONSTRUCTOR_MARKER).also { this.constructorRef =
        it }
    return localConstructor.newInstance(
        id ?: throw Util.missingProperty("id", "id", reader),
        null,
        mask0,
        null
    )
  }

  public override fun toJson(writer: JsonWriter, value: LambdaTypeName?): Unit {
    if (value == null) {
      throw NullPointerException("value was null! Wrap in .nullSafe() to write nullable values.")
    }
    writer.beginObject()
    writer.name("id")
    stringAdapter.toJson(writer, value.id)
    writer.endObject()
  }
}

[Egorand]

Nice!