Add macro error reporting

compiler/src/dotty/tools/dotc/tastyreflect/KernelImpl.scala

@@ -29,6 +29,16 @@ class KernelImpl(val rootContext: core.Contexts.Context, val rootPosition: util.
 
   def Context_source(self: Context): java.nio.file.Path = self.compilationUnit.source.file.jpath
 
+  //
+  // REPORTING
+  //
+
+  def error(msg: => String, pos: Position)(implicit ctx: Context): Unit =
+    ctx.error(msg, pos)
+
+  def warning(msg: => String, pos: Position)(implicit ctx: Context): Unit =
+    ctx.warning(msg, pos)
+
   //
   // Settings
   //

compiler/src/dotty/tools/dotc/typer/Inliner.scala

@@ -441,6 +441,7 @@ class Inliner(call: tpd.Tree, rhsToInline: tpd.Tree)(implicit ctx: Context) {
         case tree: Ident =>
           paramProxy.get(tree.tpe) match {
             case Some(t) if tree.isTerm && t.isSingleton =>
+              // FIXME wrong span, this is the span inside the inline method
               singleton(t.dealias).withSpan(tree.span)
             case Some(t) if tree.isType =>
               TypeTree(t).withSpan(tree.span)

library/src/scala/tasty/Reflection.scala

@@ -15,6 +15,7 @@ abstract class Reflection
     with PatternOps
     with PositionOps
     with Printers
+    with ReportingOps
     with RootPosition
     with SettingsOps
     with SignatureOps

library/src/scala/tasty/reflect/Kernel.scala

@@ -138,6 +138,16 @@ trait Kernel {
   /** Returns the source file being compiled. The path is relative to the current working directory. */
   def Context_source(self: Context): java.nio.file.Path
 
+  //
+  // REPORTING
+  //
+
+  /** Report a compilation error with the given message at the given position */
+  def error(msg: => String, pos: Position)(implicit ctx: Context): Unit
+
+  /** Report a compilation warning with the given message at the given position */
+  def warning(msg: => String, pos: Position)(implicit ctx: Context): Unit
+
   //
   // Settings
   //

library/src/scala/tasty/reflect/ReportingOps.scala

@@ -0,0 +1,11 @@
+package scala.tasty.reflect
+
+trait ReportingOps extends Core {
+
+  def error(msg: => String, pos: Position)(implicit ctx: Context): Unit =
+    kernel.error(msg, pos)
+
+  def warning(msg: => String, pos: Position)(implicit ctx: Context): Unit =
+    kernel.warning(msg, pos)
+
+}

tests/neg/tasty-macro-error.check

@@ -0,0 +1,16 @@
+[486..500] in quoted_2.scala
+here is the the argument is _root_.scala.StringContext.apply(("abc", "": scala.<repeated>[scala#Predef.String])).s(("def": scala.<repeated>[scala.Any]))
+[453..466] in quoted_2.scala
+here is the the argument is ("abc": scala.Predef.String)
+[407..408] in quoted_2.scala
+here is the the argument is d
+[386..387] in quoted_2.scala
+here is the the argument is c
+[309..323] in quoted_2.scala
+here is the the argument is _root_.scala.StringContext.apply(("abc", "": scala.<repeated>[scala#Predef.String])).s(("def": scala.<repeated>[scala.Any]))
+[277..290] in quoted_2.scala
+here is the the argument is ("abc": scala.Predef.String)
+[233..234] in quoted_2.scala
+here is the the argument is d
+[213..214] in quoted_2.scala
+here is the the argument is c

tests/neg/tasty-macro-error/quoted_1.scala

@@ -0,0 +1,25 @@
+import scala.quoted._
+
+import scala.tasty._
+
+object Macros {
+
+  inline def fun(x: Any): Unit = ${ impl('x) }
+
+  inline def fun2(x: =>Any): Unit = ${ impl('x) }
+
+  inline def fun3[T]: Unit = ${ impl2('[T]) }
+
+  def impl(x: Expr[Any])(implicit reflect: Reflection): Expr[Unit] = {
+    import reflect._
+    error("here is the the argument is " + x.unseal.underlyingArgument.showCode, x.unseal.underlyingArgument.pos)
+    '{}
+  }
+
+  def impl2[T](x: quoted.Type[T])(implicit reflect: Reflection): Expr[Unit] = {
+    import reflect._
+    error("here is the the argument is " + x.unseal.showCode, x.unseal.pos)
+    '{}
+  }
+
+}

tests/neg/tasty-macro-error/quoted_2.scala

@@ -0,0 +1,38 @@
+
+import Macros._
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    val a: String = "abc"
+    val b: 42 = 42
+    def c: String = "abc"
+    def d: 42 = 42
+
+//  fun(a) // ERROR
+//  fun(b) // ERROR
+    fun(c) // error
+    fun(d) // error
+//  fun("abc") // ERROR
+    fun("abc": String) // error
+    fun(s"abc${"def"}") // error
+
+//  fun2(a) // ERROR
+//  fun2(b) // ERROR
+    fun2(c) // error
+    fun2(d) // error
+//  fun2("abc") // ERROR
+    fun2("abc": String) // error
+    fun2(s"abc${"def"}") // error
+
+//    type T
+//    type U = "abc"
+//
+//    fun3[T] // ERROR
+//    fun3[String] // ERROR
+//    fun3["abc"] // ERROR
+//    fun3[U] // ERROR
+  }
+// FIXME all the lines marked as ERROR have the wrong position on the three of the argument.
+// they all have as source file this file but the span of `'x` in `fun` or `fun2`.
+// see #6026 and #6027
+}