Emit inline errors at expansion site

Author: nicolasstucki

compiler/src/dotty/tools/dotc/reporting/MessageRendering.scala

@@ -33,7 +33,7 @@ trait MessageRendering {
     */
   def outer(pos: SourcePosition, prefix: String)(implicit ctx: Context): List[String] =
     if (pos.outer.exists)
-       i"$prefix| This location is in code that was inlined at ${pos.outer}" ::
+       i"$prefix| This location is in code that was inlined at $pos" ::
        outer(pos.outer, prefix)
     else Nil
 
@@ -149,9 +149,10 @@ trait MessageRendering {
     val posString = posStr(pos, diagnosticLevel, msg)
     if (posString.nonEmpty) sb.append(posString).append(EOL)
     if (pos.exists && pos.source.file.exists) {
-      val (srcBefore, srcAfter, offset) = sourceLines(pos, diagnosticLevel)
-      val marker = columnMarker(pos, offset, diagnosticLevel)
-      val err = errorMsg(pos, msg.msg, offset)
+      val pos1 = pos.nonInlined
+      val (srcBefore, srcAfter, offset) = sourceLines(pos1, diagnosticLevel)
+      val marker = columnMarker(pos1, offset, diagnosticLevel)
+      val err = errorMsg(pos1, msg.msg, offset)
       sb.append((srcBefore ::: marker :: err :: outer(pos, " " * (offset - 1)) ::: srcAfter).mkString(EOL))
     }
     else sb.append(msg.msg)

compiler/src/dotty/tools/dotc/util/SourcePosition.scala

@@ -64,6 +64,17 @@ extends interfaces.SourcePosition with Showable {
   def outermost: SourcePosition =
     if outer == null || outer == NoSourcePosition then this else outer.outermost
 
+  /** Inner most position that is contained within the `outermost` position.
+   *  Most precise position that that comes from the call site.
+   */
+  def nonInlined: SourcePosition = {
+    val om = outermost
+    def rec(self: SourcePosition): SourcePosition =
+      if outermost.contains(self) then self else rec(self.outer)
+    rec(this)
+  }
+
+
   override def toString: String =
     s"${if (source.exists) source.file.toString else "(no source)"}:$span"
 

compiler/test/dotty/tools/vulpix/ParallelTesting.scala

@@ -679,11 +679,12 @@ trait ParallelTesting extends RunnerOrchestration { self =>
     }
 
     def getMissingExpectedErrors(errorMap: HashMap[String, Integer], reporterErrors: Iterator[MessageContainer]) = !reporterErrors.forall { error =>
-      val key = if (error.pos.exists) {
+      val pos1 = error.pos.nonInlined
+      val key = if (pos1.exists) {
         def toRelative(path: String): String =  // For some reason, absolute paths leak from the compiler itself...
           path.split("/").dropWhile(_ != "tests").mkString("/")
-        val fileName = toRelative(error.pos.source.file.toString)
-        s"$fileName:${error.pos.line}"
+        val fileName = toRelative(pos1.source.file.toString)
+        s"$fileName:${pos1.line}"
 
       } else "nopos"
 
@@ -695,7 +696,7 @@ trait ParallelTesting extends RunnerOrchestration { self =>
         true
       }
       else {
-        echo(s"Error reported in ${error.pos.source}, but no annotation found")
+        echo(s"Error reported in ${pos1.source}, but no annotation found")
         false
       }
     }

tests/neg-macros/macros-in-same-project-2.scala

@@ -3,9 +3,9 @@ import scala.quoted._
 
 object Bar {
 
-  myMacro()
+  myMacro() // error
 
-  inline def myMacro(): Unit = myMacro2() // error
+  inline def myMacro(): Unit = myMacro2()
   inline def myMacro2(): Unit = ${ aMacroImplementation }
 
   def aMacroImplementation(given QuoteContext): Expr[Unit] = '{}

tests/neg/cannot-reduce-inline-match.check

@@ -1,11 +1,9 @@
 -- Error: tests/neg/cannot-reduce-inline-match.scala:3:13 --------------------------------------------------------------
-3 |    inline x match { // error
-  |           ^
-  |           cannot reduce inline match with
-  |            scrutinee:  {
-  |             "f"
-  |           } : String("f")
-  |            patterns :  case _:Int
-  | This location is in code that was inlined at cannot-reduce-inline-match.scala:9
-4 |      case _: Int =>
-5 |    }
+9 |  foo("f") // error
+  |  ^^^^^^^^
+  |  cannot reduce inline match with
+  |   scrutinee:  {
+  |    "f"
+  |  } : String("f")
+  |   patterns :  case _:Int
+  | This location is in code that was inlined at cannot-reduce-inline-match.scala:3

tests/neg/cannot-reduce-inline-match.scala

@@ -1,11 +1,11 @@
 object Test {
   inline def foo[T](x: T) =
-    inline x match { // error
+    inline x match {
       case _: Int =>
     }
 
   foo(4)
 
-  foo("f")
+  foo("f") // error
 
 }

tests/neg/cannot-reduce-summonFrom.scala

@@ -1,7 +1,7 @@
 object Test {
 
   inline def bar() =
-    compiletime.summonFrom {  // error
+    compiletime.summonFrom {
       case _: Int =>
     }
 
@@ -10,5 +10,5 @@ object Test {
     bar()
   }
 
-  bar()
+  bar() // error
 }

tests/neg/i6371/A_1.scala

@@ -1,6 +1,6 @@
 object A {
   inline def foo(a: Any): Unit = a match {
-    case _: Int => // error
+    case _: Int =>
     case _ =>
   }
 }

tests/neg/i6371/B_2.scala

@@ -1,3 +1,3 @@
 object B {
-  A.foo("aa")
+  A.foo("aa") // error
 }

tests/neg/inline-error-pos.check

@@ -0,0 +1,9 @@
+-- Error: tests/neg/inline-error-pos.scala:3:11 ------------------------------------------------------------------------
+8 |  val b = foo(2) // error
+  |          ^^^^^^
+  |          cannot reduce inline match with
+  |           scrutinee:  {
+  |            2
+  |          } : Int(2)
+  |           patterns :  case 1
+  | This location is in code that was inlined at inline-error-pos.scala:3