Add TASTy reflect error with custom positions

Having custom positions is necessary to emit errors inside string interpolators such as

```scala
xml"<a><<b></a>"
       ^^ Some parsing error here
```

Author: nicolasstucki

community-build/community-projects/minitest

@@ -36,9 +36,15 @@ class KernelImpl(val rootContext: core.Contexts.Context, val rootPosition: util.
   def error(msg: => String, pos: Position)(implicit ctx: Context): Unit =
     ctx.error(msg, pos)
 
+  def error(msg: => String, sourceFile: SourceFile, start: Int, end: Int)(implicit ctx: Context): Unit =
+    ctx.error(msg, util.SourcePosition(sourceFile, util.Spans.Span(start, end)))
+
   def warning(msg: => String, pos: Position)(implicit ctx: Context): Unit =
     ctx.warning(msg, pos)
 
+  def warning(msg: => String, sourceFile: SourceFile, start: Int, end: Int)(implicit ctx: Context): Unit =
+    ctx.error(msg, util.SourcePosition(sourceFile, util.Spans.Span(start, end)))
+
   //
   // Settings
   //
@@ -1297,7 +1303,7 @@ class KernelImpl(val rootContext: core.Contexts.Context, val rootPosition: util.
 
   def Position_exists(self: Position): Boolean = self.exists
 
-  def Position_sourceFile(self: Position): java.nio.file.Path = self.source.file.jpath
+  def Position_sourceFile(self: Position): SourceFile = self.source
 
   def Position_startLine(self: Position): Int = self.startLine
 
@@ -1310,6 +1316,16 @@ class KernelImpl(val rootContext: core.Contexts.Context, val rootPosition: util.
   def Position_sourceCode(self: Position): String =
     new String(self.source.content(), self.start, self.end - self.start)
 
+  //
+  // SOURCE FILES
+  //
+
+  type SourceFile = util.SourceFile
+
+  def SourceFile_jpath(self: SourceFile): java.nio.file.Path = self.file.jpath
+
+  def SourceFile_content(self: SourceFile): String = new String(self.content())
+
   //
   // COMMENTS
   //

community-build/community-projects/sourcecode

@@ -407,9 +407,12 @@ trait Core {
   /** JVM signature of a method */
   type Signature = kernel.Signature
 
-  /** Source position */
+  /** Position in a source file */
   type Position = kernel.Position
 
+  /** Scala source file */
+  type SourceFile = kernel.SourceFile
+
   /** Comment */
   type Comment = kernel.Comment
 

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

@@ -145,9 +145,15 @@ trait Kernel {
   /** 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 error with the given message at the given position range */
+  def error(msg: => String, source: SourceFile, start: Int, end: Int)(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
 
+  /** Report a compilation warning with the given message at the given position range */
+  def warning(msg: => String, source: SourceFile, start: Int, end: Int)(implicit ctx: Context): Unit
+
   //
   // Settings
   //
@@ -1037,7 +1043,7 @@ trait Kernel {
   // POSITIONS
   //
 
-  /** Source position */
+  /** Position in a source file */
   type Position <: AnyRef
 
   /** The start offset in the source file */
@@ -1050,7 +1056,7 @@ trait Kernel {
   def Position_exists(self: Position): Boolean
 
   /** Source file in which this position is located */
-  def Position_sourceFile(self: Position): java.nio.file.Path
+  def Position_sourceFile(self: Position): SourceFile
 
   /** The start line in the source file */
   def Position_startLine(self: Position): Int
@@ -1067,6 +1073,19 @@ trait Kernel {
   /** Source code within the position */
   def Position_sourceCode(self: Position): String
 
+  //
+  // SOURCE FILE
+  //
+
+  /** Scala source file */
+  type SourceFile <: AnyRef
+
+  /** Path to a source file */
+  def SourceFile_jpath(self: SourceFile): java.nio.file.Path
+
+  /** Content of a source file */
+  def SourceFile_content(self: SourceFile): String
+
   //
   // COMMENTS
   //

library/src/scala/tasty/reflect/Core.scala

@@ -14,7 +14,7 @@ trait PositionOps extends Core {
     def exists: Boolean = kernel.Position_exists(pos)
 
     /** Source file in which this position is located */
-    def sourceFile: java.nio.file.Path = kernel.Position_sourceFile(pos)
+    def sourceFile: SourceFile = kernel.Position_sourceFile(pos)
 
     /** The start line in the source file */
     def startLine: Int = kernel.Position_startLine(pos)
@@ -33,4 +33,14 @@ trait PositionOps extends Core {
 
   }
 
+  implicit class SourceFileAPI(sourceFile: SourceFile) {
+
+    /** Path to this source file */
+    def jpath: java.nio.file.Path = kernel.SourceFile_jpath(sourceFile)
+
+    /** Content of this source file */
+    def content: String = kernel.SourceFile_content(sourceFile)
+
+  }
+
 }

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

@@ -5,7 +5,12 @@ trait ReportingOps extends Core {
   def error(msg: => String, pos: Position)(implicit ctx: Context): Unit =
     kernel.error(msg, pos)
 
+  def error(msg: => String, source: SourceFile, start: Int, end: Int)(implicit ctx: Context): Unit =
+    kernel.error(msg, source, start, end)
+
   def warning(msg: => String, pos: Position)(implicit ctx: Context): Unit =
     kernel.warning(msg, pos)
 
+  def warning(msg: => String, source: SourceFile, start: Int, end: Int)(implicit ctx: Context): Unit =
+    kernel.warning(msg, source, start, end)
 }

library/src/scala/tasty/reflect/PositionOps.scala

@@ -0,0 +1,4 @@
+<122..125> in quoted_2.scala
+here (+5) is the the argument is foo
+[117..120] in quoted_2.scala
+here is the the argument is foo

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

@@ -0,0 +1,17 @@
+import scala.quoted._
+
+import scala.tasty._
+
+object Macros {
+
+  inline def fun(x: Any): Unit = ${ impl('x) }
+
+  def impl(x: Expr[Any])(implicit reflect: Reflection): Expr[Unit] = {
+    import reflect._
+    val pos = x.unseal.underlyingArgument.pos
+    error("here is the the argument is " + x.unseal.underlyingArgument.showCode, pos)
+    error("here (+5) is the the argument is " + x.unseal.underlyingArgument.showCode, pos.sourceFile, pos.start + 5, pos.end + 5)
+    '{}
+  }
+
+}

tests/neg/tasty-macro-positions.check

@@ -0,0 +1,11 @@
+
+import Macros._
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    def foo: String = "abc"
+    fun(
+      foo // error // error
+    )
+  }
+}

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

@@ -32,6 +32,6 @@ object Macros {
 
   def posStr(relfection: Reflection)(pos: relfection.Position): Expr[String] = {
     import relfection._
-    s"${pos.sourceFile.getFileName.toString}:[${pos.start}..${pos.end}]".toExpr
+    s"${pos.sourceFile.jpath.getFileName.toString}:[${pos.start}..${pos.end}]".toExpr
   }
 }

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

@@ -15,7 +15,7 @@ object Positioned {
     import reflect.{Position => _, _}
     val pos = rootPosition
 
-    val path = pos.sourceFile.toString.toExpr
+    val path = pos.sourceFile.jpath.toString.toExpr
     val start = pos.start.toExpr
     val end = pos.end.toExpr
     val startLine = pos.startLine.toExpr