Construct root instances with factory methods (#192)

* Construct root instance with given factory methods

* Add todo for partial applied functions

macrosAutoCats/src/main/scala/com/softwaremill/macwire/autocats/internals/CatsProvidersGraphContext.scala

@@ -90,7 +90,7 @@ class CatsProvidersGraphContext[C <: blackbox.Context](val c: C, val log: Logger
     /** We assume that we cannot use input provider directly, so we create a result object with available constructors.
       * It's a mimic of `wire`'s property
       */
-    val (resolvedCtx, rootProvider) = maybeResolveParamWithCreator(resolvedFMContext)(rootType)
+    val (resolvedCtx, rootProvider) = (maybeResolveWithFactoryMethod(resolvedFMContext)(rootType) orElse maybeResolveParamWithCreator(resolvedFMContext)(rootType))
       .getOrElse(c.abort(c.enclosingPosition, s"Cannot construct an instance of type: [$rootType]"))
 
     val inputProvidersTypes = inputProviders
@@ -119,6 +119,11 @@ class CatsProvidersGraphContext[C <: blackbox.Context](val c: C, val log: Logger
     inputProviders ++ resultContext.providers.diff(inputProviders)
   }
 
+  private def maybeResolveWithFactoryMethod(ctx: BuilderContext)(param: c.Type): Option[(BuilderContext, Provider)] = ctx.providers.find {
+    case fm: FactoryMethod => fm.resultType <:< param
+    case _ => false
+  }.map(r => (ctx, r))
+
   private def maybeResolveParamWithCreator(ctx: BuilderContext)(param: c.Type): Option[(BuilderContext, FactoryMethod)] =
     log.withBlock(s"Resolving creator for [$param]") {
       def maybeResolveParams(

macrosAutoCatsTests/src/test/resources/test-cases/constructInstanceWithFactoryMethod.success

@@ -0,0 +1,20 @@
+class A()
+class B(val a: A)
+
+val created = scala.collection.mutable.ListBuffer[String]()
+
+def makeB(a: A) = {created.append("b"); new B(a)}
+
+object Test {
+    val theB = autowire[B](makeB _)
+
+}
+
+val theB: B = {
+    import cats.effect.unsafe.implicits.global
+    Test.theB.allocated.unsafeRunSync()._1
+}
+
+require(theB.a != null)
+require(created.size == 1)
+require(created(0) == "b")

macrosAutoCatsTests/src/test/resources/test-cases/todo/passSomeParameters.success

@@ -0,0 +1,21 @@
+class A()
+class B(val a: A)
+
+val created = scala.collection.mutable.ListBuffer[String]()
+
+def makeB(s: String, a: A) = { created.append("b"); created.append(s); new B(a)}
+
+object Test {
+    val theB = autowire[B](makeB("s", _))
+
+}
+
+val theB: B = {
+    import cats.effect.unsafe.implicits.global
+    Test.theB.allocated.unsafeRunSync()._1
+}
+
+require(theB.a != null)
+require(created.size == 2)
+require(created(0) == "b")
+require(created(0) == "s")