Add implicit reporter for inline quotes

Author: nicolasstucki

compiler/src/dotty/tools/dotc/core/Definitions.scala

@@ -635,6 +635,10 @@ class Definitions {
     lazy val QuotedType_applyR = QuotedTypeModule.requiredMethodRef(nme.apply)
     def QuotedType_apply(implicit ctx: Context) = QuotedType_applyR.symbol
 
+  lazy val QuotedReporterModule = ctx.requiredModule("scala.quoted.Reporter")
+    lazy val QuotedReporterDummyR = QuotedReporterModule.requiredMethod("dummy".toTermName)
+    def QuotedReporterDummy(implicit ctx: Context) = QuotedReporterDummyR.symbol
+
   def Unpickler_unpickleExpr = ctx.requiredMethod("scala.runtime.quoted.Unpickler.unpickleExpr")
   def Unpickler_unpickleType = ctx.requiredMethod("scala.runtime.quoted.Unpickler.unpickleType")
 

compiler/src/dotty/tools/dotc/interpreter/Interpreter.scala

@@ -72,6 +72,12 @@ class Interpreter(implicit ctx: Context) {
         if (quotedTree.isTerm) new scala.quoted.Exprs.TreeExpr(quotedTree)
         else new scala.quoted.Types.TreeType(quotedTree)
 
+      case tree: RefTree if tree.symbol eq defn.QuotedReporterDummy =>
+        new scala.quoted.Reporter {
+          override def error(message: String): Unit = ctx.error(message, pos)
+          override def warn(message: String): Unit = ctx.warning(message, pos)
+        }
+
       case Literal(Constant(c)) => c.asInstanceOf[Object]
 
       case Apply(fn, args) if fn.symbol.isConstructor =>

library/src/scala/quoted/Reporter.scala

@@ -0,0 +1,14 @@
+package scala.quoted
+
+trait Reporter {
+  def error(message: String): Unit
+  def warn(message: String): Unit
+}
+
+object Reporter {
+  object DummyReporter extends Reporter {
+    override def error(message: String): Unit = ()
+    override def warn(message: String): Unit = ()
+  }
+  implicit def dummy: Reporter = DummyReporter
+}

tests/neg/quote-reporter/Macro_1.scala

@@ -0,0 +1,8 @@
+import quoted._
+
+object Macro_1 {
+  inline def foo(inline b: Boolean): Unit = ~fooImpl(b)
+  def fooImpl(b: Boolean)(implicit reporter: Reporter): Expr[Unit] =
+    if (b) '(println("foo(true)"))
+    else reporter.error("foo cannot be called with false")
+}

tests/neg/quote-reporter/Test_2.scala

@@ -0,0 +1,6 @@
+import Macro_1._
+
+object Test_2 {
+  foo(true)
+  foo(false) // error: foo cannot be called with false
+}