Show message when using unsupported by-name parameters (zio#8117)

* Show message when using unsupported by-name parameters

* Formatting

* Code review fixes

* Make error message much nicer (hopefully)

Author: andrzejressel

core-tests/shared/src/test/scala/zio/autowire/AutoWireSpec.scala

@@ -2,7 +2,7 @@ package zio.autowire
 
 import zio._
 import zio.internal.macros.StringUtils.StringOps
-import zio.test.Assertion.{equalTo, isLeft}
+import zio.test.Assertion.{anything, equalTo, isLeft}
 import zio.test._
 
 object AutoWireSpec extends ZIOBaseSpec {
@@ -147,6 +147,41 @@ object AutoWireSpec extends ZIOBaseSpec {
                   containsStringWithoutAnsi("Double")
               )
             )
+          } @@ TestAspect.exceptScala3,
+          test("works corrently with function parameters") {
+            case class MyLayer()
+
+            def createLayerByFunction(x: () => MyLayer) = ZLayer.succeed(x())
+
+            val byName =
+              ZIO
+                .service[MyLayer]
+                .provide(
+                  createLayerByFunction { () =>
+                    val byNameLayer = MyLayer()
+                    byNameLayer
+                  }
+                )
+            assertTrue(byName != null)
+          },
+          test("return error when passing by-name on Scala 2 (https://github.com/zio/zio/issues/7732)") {
+            assertZIO(typeCheck {
+              """
+                case class MyLayer()
+
+                def createLayerByName(x: => MyLayer) = ZLayer.succeed(x)
+
+                val byName =
+                  ZIO
+                    .service[MyLayer]
+                    .provide(
+                      createLayerByName {
+                        val byNameLayer = MyLayer()
+                        byNameLayer
+                      }
+                    )
+              """
+            })(isLeft(anything))
           } @@ TestAspect.exceptScala3
         ),
         suite("`ZLayer.makeSome`")(

core/shared/src/main/scala-2/zio/internal/macros/LayerMacroUtils.scala

@@ -1,6 +1,8 @@
 package zio.internal.macros
 
 import zio._
+import zio.internal.TerminalRendering
+
 import scala.reflect.macros.blackbox
 
 private[zio] trait LayerMacroUtils {
@@ -9,11 +11,38 @@ private[zio] trait LayerMacroUtils {
 
   type LayerExpr = c.Expr[ZLayer[_, _, _]]
 
+  private def verifyLayers(layers: Seq[c.Expr[ZLayer[_, _, _]]]): Unit =
+    for (layer <- layers) {
+      layer.tree match {
+        case Apply(tree, _) =>
+          tree.tpe match {
+            case MethodType(params, _) =>
+              val methodName          = tree.toString()
+              val fullMethodSignature = s"def $methodName${tree.tpe}"
+
+              val byNameParameters =
+                params.filter(s => isByName(s.typeSignature)).map(s => s"${s.name}: ${s.typeSignature}")
+
+              if (byNameParameters.nonEmpty) {
+                c.abort(
+                  NoPosition,
+                  TerminalRendering.byNameParameterInMacroError(methodName, fullMethodSignature, byNameParameters)
+                )
+              }
+          }
+        case _ => ()
+      }
+    }
+
+  private def isByName(tpe: c.Type): Boolean =
+    tpe.typeSymbol.isClass && tpe.typeSymbol.asClass == c.universe.definitions.ByNameParamClass
+
   def constructLayer[R0: c.WeakTypeTag, R: c.WeakTypeTag, E](
     layers: Seq[c.Expr[ZLayer[_, E, _]]],
     provideMethod: ProvideMethod
   ): c.Expr[ZLayer[R0, E, R]] = {
 
+    verifyLayers(layers)
     val remainderTypes = getRequirements[R0]
     val targetTypes    = getRequirements[R]
 

internal-macros/shared/src/main/scala/zio/internal/TerminalRendering.scala

@@ -1,9 +1,8 @@
 package zio.internal
 
-import ansi._
+import zio.internal.ansi._
 
 object TerminalRendering {
-
   def circularityError(circularDependencies: List[(String, String)]): String = {
     val circularDependencyMessage =
       circularDependencies.map { case (a0, b0) =>
@@ -210,6 +209,45 @@ object TerminalRendering {
        |""".stripMargin
   }
 
+  private def colorMethodSignature(fullMethodSignature: String, parametersToColor: Seq[String], color: Color): String =
+    parametersToColor.fold(fullMethodSignature) { (signature, parameter) =>
+      signature.replace(parameter, parameter.withAnsi(color))
+    }
+
+  private def replaceByNameWithLambdasAndColorMethodSignature(
+    fullMethodSignature: String,
+    parametersToColor: Seq[String],
+    color: Color
+  ): String =
+    parametersToColor.fold(fullMethodSignature) { (signature, parameter) =>
+      signature.replace(parameter, parameter.replace("=>", "() =>").withAnsi(color))
+    }
+
+  def byNameParameterInMacroError(method: String, fullMethodSignature: String, byNameParameters: Seq[String]): String =
+    s"""
+       |${title("ZLayer Error").red}
+       |
+       | Due to bug in Scala 2 compiler invoking methods with by-name parameters in ${methodName(
+      "provide"
+    )}/${methodName("provideSome")} method does not work
+       | ${colorMethodSignature(fullMethodSignature, byNameParameters, Color.Red)}
+       |
+       | Bug can be workarounded in following ways:
+       |
+       | 1. Assign method output to temporary variable
+       |    ${s"ZLayer.provide($method(...))".red}
+       |    ↓↓↓
+       |    ${s"val temp = $method(...)".green}
+       |    ${s"ZLayer.provide(temp)".green}
+       |
+       | 2. Replace by-name parameter with lambda:
+       |    ${colorMethodSignature(fullMethodSignature, byNameParameters, Color.Red)}
+       |    ↓↓↓
+       |    ${replaceByNameWithLambdasAndColorMethodSignature(fullMethodSignature, byNameParameters, Color.Green)}
+       |
+       |${line.red}
+       |""".stripMargin
+
   def provideSomeNothingEnvError: String =
     s"""${title("ZLayer Warning").yellow}
 
@@ -248,6 +286,13 @@ ${line.yellow}
         )
       )
     )
+    println(
+      byNameParameterInMacroError(
+        "createLayerByName",
+        "def createLayerByName(i: Int, x: => MyLayer): zio.ULayer[MyLayer]",
+        Seq("x: => MyLayer")
+      )
+    )
   }
 
   /**