unused

macros/src/main/scala-3/com/softwaremill/macwire/internals/autowire/AutowireGraph.scala

@@ -1,6 +1,7 @@
 package com.softwaremill.macwire.internals.autowire
 
 import scala.quoted.Quotes
+import scala.quoted.Expr
 
 class AutowireGraph[Q <: Quotes](using val q: Q):
   import q.reflect.*
@@ -9,7 +10,8 @@ class AutowireGraph[Q <: Quotes](using val q: Q):
       tpe: TypeRepr, // the type of the instance that will be created
       symbol: Symbol, // the symbol of the val-def that will hold the instance
       dependencies: List[Symbol], // incoming edges: the nodes for types that need to be created before this one
-      createInstance: Term // code to create an instance of `tpe`
+      createInstance: Term, // code to create an instance of `tpe`
+      raw: Option[Expr[Any]] // the raw dependency as provided by the user, if any
   )
 
   /** A fully resolved graph, i.e. for each node's dependency there's a node with that symbol. */

macros/src/main/scala-3/com/softwaremill/macwire/internals/autowire/ReportError.scala

@@ -14,6 +14,7 @@ class ReportError[Q <: Quotes](using val q: Q):
     finally path = path.init
 
   def apply(msg: String): Nothing =
-    report.errorAndAbort(s"$msg\nWiring path: $showPath")
+    val suffix = if path.nonEmpty then s"\nWiring path: $showPath" else ""
+    report.errorAndAbort(s"$msg$suffix")
 
   private def showPath: String = path.map(showTypeName).mkString(" -> ")

macros/src/main/scala-3/com/softwaremill/macwire/internals/autowire/autowireImpl.scala

@@ -73,7 +73,7 @@ def autowireImpl[T: Type](dependencies: Expr[Seq[Any]])(using q: Quotes): Expr[T
                 Symbol.noSymbol
               )
             val updatedGraph2 = updatedGraph.addNode(
-              Node(t, tSymbol, dependencySymbols, tProvider.create(dependencySymbols.map(Ref(_))))
+              Node(t, tSymbol, dependencySymbols, tProvider.create(dependencySymbols.map(Ref(_))), tProvider.raw)
             )
 
             (tSymbol, updatedGraph2)
@@ -89,14 +89,24 @@ def autowireImpl[T: Type](dependencies: Expr[Seq[Any]])(using q: Quotes): Expr[T
       case '[Int] | '[Long] | '[Byte] | '[Short] | '[Char] | '[Boolean] | '[Double] | '[Float] | '[String] =>
         reportError(s"Cannot use a primitive type or String in autowiring.")
       case _ => // ok
+  end verifyNotPrimitive
+
+  def verifyEachDependencyUsed(nodes: Vector[Node]): Unit =
+    val usedDependencies = nodes.flatMap(_.raw).toSet
+    val unusedDependencies = rawDependencies.filterNot(usedDependencies.contains)
+    if unusedDependencies.nonEmpty then
+      reportError(
+        s"Unused dependencies: ${unusedDependencies.map(_.asTerm.show(using Printer.TreeShortCode)).mkString(", ")}."
+      )
+
   //
 
   val t = TypeRepr.of[T]
   val (rootSymbol, fullGraph) = expandGraph(t, Graph(Vector.empty), Vector.empty)
 
   // the graph is already sorted topologically: nodes are appended, and added only once all dependencies are present
 
-  // TODO: verify each dependency used
+  verifyEachDependencyUsed(fullGraph.nodes)
 
   val code = Block(
     fullGraph.nodes.map(node => ValDef(node.symbol, Some(node.createInstance))).toList,

tests/src/test/resources/test-cases/autowire/simpleAllDependencies.success → tests/src/test/resources/test-cases/autowire/simpleTwoDependencies.success

@@ -5,8 +5,7 @@ case class D(c: C)
 
 val a = A()
 val b = B()
-val c = C(a, b)
-val d = D(c)
-val d2 = autowire[D](a, b, c, d)
+val d = autowire[D](a, b)
 
-require (d2 eq d)
+require (d.c.a eq a)
+require (d.c.b eq b)

tests/src/test/resources/test-cases/autowire/unusedDependency.failure

@@ -0,0 +1,5 @@
+case class A()
+case class B(a: A)
+case class C()
+
+autowire[B](C())

tests/src/test/scala-3/com/softwaremill/macwire/AutowireCompileTests.scala

@@ -10,6 +10,7 @@ class AutowireCompileTests extends CompileTestsSupport:
         "Wiring path: A"
       ),
       "cyclicDependency" -> List("Cyclic dependencies detected.", "Wiring path: A -> B -> A"),
-      "primitives" -> List("Cannot use a primitive type or String in autowiring.", "Wiring path: A -> String")
+      "primitives" -> List("Cannot use a primitive type or String in autowiring.", "Wiring path: A -> String"),
+      "unusedDependency" -> List("Unused dependencies: C.apply().")
     )
   )