Remove differences in diagnostic printing in the REPL

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

@@ -107,15 +107,19 @@ trait MessageRendering {
       .mkString(EOL)
   }
 
+  /** The source file path, line and column numbers from the given SourcePosition */
+  def posFileStr(pos: SourcePosition): String =
+    val path = pos.source.file.path
+    if pos.exists then s"$path:${pos.line + 1}:${pos.column}" else path
+
   /** The separator between errors containing the source file and error type
     *
     * @return separator containing error location and kind
     */
   def posStr(pos: SourcePosition, diagnosticLevel: String, message: Message)(using Context): String =
     if (pos.source != NoSourcePosition.source) hl(diagnosticLevel)({
-      val pos1 = pos.nonInlined
-      val file = if !pos.exists then pos1.source.file.toString else
-        s"${pos1.source.file.toString}:${pos1.line + 1}:${pos1.column}"
+      val fileAndPos = posFileStr(pos.nonInlined)
+      val file = if fileAndPos.isEmpty || fileAndPos.endsWith(" ") then fileAndPos else s"$fileAndPos "
       val errId =
         if (message.errorId ne ErrorMessageID.NoExplanationID) {
           val errorNumber = message.errorId.errorNumber
@@ -124,7 +128,7 @@ trait MessageRendering {
       val kind =
         if (message.kind == "") diagnosticLevel
         else s"${message.kind} $diagnosticLevel"
-      val prefix = s"-- ${errId}${kind}: $file "
+      val prefix = s"-- ${errId}${kind}: $file"
 
       prefix +
         ("-" * math.max(ctx.settings.pageWidth.value - stripColor(prefix).length, 0))
@@ -192,12 +196,13 @@ trait MessageRendering {
 
   def diagnosticLevel(dia: Diagnostic): String =
     dia match {
-      case dia: Error => "Error"
       case dia: FeatureWarning => "Feature Warning"
       case dia: DeprecationWarning => "Deprecation Warning"
       case dia: UncheckedWarning => "Unchecked Warning"
       case dia: MigrationWarning => "Migration Warning"
-      case dia: Warning => "Warning"
-      case dia: Info => "Info"
+      case _ => dia.level match // Diagnostic isn't sealed (e.g. created in the REPL) so provide a fallback
+        case interfaces.Diagnostic.ERROR   => "Error"
+        case interfaces.Diagnostic.WARNING => "Warning"
+        case interfaces.Diagnostic.INFO    => "Info"
     }
 }

compiler/src/dotty/tools/repl/Rendering.scala

@@ -31,12 +31,6 @@ private[repl] class Rendering(parentClassLoader: Option[ClassLoader] = None) {
 
   private val MaxStringElements: Int = 1000  // no need to mkString billions of elements
 
-  /** A `MessageRenderer` for the REPL without file positions */
-  private val messageRenderer = new MessageRendering {
-    override def posStr(pos: SourcePosition, diagnosticLevel: String, message: Message)(using Context): String =
-      hl(diagnosticLevel)(s"-- $diagnosticLevel:")
-  }
-
   private var myClassLoader: ClassLoader = _
 
   private var myReplStringOf: Object => String = _
@@ -126,14 +120,6 @@ private[repl] class Rendering(parentClassLoader: Option[ClassLoader] = None) {
       }
   }
 
-  /** Formats errors using the `messageRenderer` */
-  def formatError(dia: Diagnostic)(implicit state: State): Diagnostic =
-    new Diagnostic(
-      messageRenderer.messageAndPos(dia)(using state.context),
-      dia.pos,
-      dia.level
-    )
-
   def renderTypeDef(d: Denotation)(using Context): Diagnostic =
     infoDiagnostic("// defined " ++ d.symbol.showUser, d)
 

compiler/src/dotty/tools/repl/ReplCompiler.scala

@@ -153,6 +153,7 @@ class ReplCompiler extends Compiler {
   private def runCompilationUnit(unit: CompilationUnit, state: State): Result[(CompilationUnit, State)] = {
     val ctx = state.context
     ctx.run.compileUnits(unit :: Nil)
+    ctx.run.printSummary() // this outputs "2 errors found" like normal - but we might decide that's needlessly noisy for the REPL
 
     if (!ctx.reporter.hasErrors) (unit, state).result
     else ctx.reporter.removeBufferedMessages(using ctx).errors

compiler/src/dotty/tools/repl/ReplDriver.scala

@@ -1,6 +1,6 @@
 package dotty.tools.repl
 
-import java.io.{File => JFile, PrintStream}
+import java.io.{File => JFile, PrintStream, PrintWriter}
 import java.nio.charset.StandardCharsets
 
 import dotty.tools.dotc.ast.Trees._
@@ -17,9 +17,10 @@ import dotty.tools.dotc.core.NameOps._
 import dotty.tools.dotc.core.Names.Name
 import dotty.tools.dotc.core.StdNames._
 import dotty.tools.dotc.core.Symbols.{Symbol, defn}
+import dotty.tools.dotc.interfaces
 import dotty.tools.dotc.interactive.Completion
 import dotty.tools.dotc.printing.SyntaxHighlighting
-import dotty.tools.dotc.reporting.{MessageRendering, StoreReporter}
+import dotty.tools.dotc.reporting.{ConsoleReporter, MessageRendering, StoreReporter}
 import dotty.tools.dotc.reporting.{Message, Diagnostic}
 import dotty.tools.dotc.util.Spans.Span
 import dotty.tools.dotc.util.{SourceFile, SourcePosition}
@@ -261,7 +262,6 @@ class ReplDriver(settings: Array[String],
 
             val warnings = newState.context.reporter
               .removeBufferedMessages(using newState.context)
-              .map(rendering.formatError)
 
             inContext(newState.context) {
               val (updatedState, definitions) =
@@ -278,8 +278,7 @@ class ReplDriver(settings: Array[String],
 
               (definitions ++ warnings)
                 .sorted
-                .map(_.msg)
-                .foreach(out.println)
+                .foreach(printDiagnostic)
 
               updatedState
             }
@@ -422,7 +421,20 @@ class ReplDriver(settings: Array[String],
 
   /** shows all errors nicely formatted */
   private def displayErrors(errs: Seq[Diagnostic])(implicit state: State): State = {
-    errs.map(rendering.formatError).map(_.msg).foreach(out.println)
+    errs.foreach(printDiagnostic)
     state
   }
+
+  /** Like ConsoleReporter, but without file paths or real -Xprompt'ing */
+  private object ReplConsoleReporter extends ConsoleReporter(
+    reader = null, // this short-circuits the -Xprompt display from waiting for an input
+    writer = new PrintWriter(out, /* autoFlush = */ true), // write to out, not Console.err
+  ) {
+    override def posFileStr(pos: SourcePosition) = "" // omit file paths
+  }
+
+  /** Print warnings & errors using ReplConsoleReporter, and info straight to out */
+  private def printDiagnostic(dia: Diagnostic)(implicit state: State) = dia.level match
+    case interfaces.Diagnostic.INFO => out.println(dia.msg) // print REPL's special info diagnostics directly to out
+    case _                          => ReplConsoleReporter.doReport(dia)(using state.context)
 }

compiler/test-resources/repl/1379

@@ -1,5 +1,6 @@
 scala>  object Foo { val bar = new Object { def baz = 1 }; bar.baz }
--- Error:
+-- [E008] Not Found Error: -----------------------------------------------------
 1 |  object Foo { val bar = new Object { def baz = 1 }; bar.baz }
   |                                                     ^^^^^^^
-  |                                       value baz is not a member of Object
+  |                                       value baz is not a member of Object
+1 error found

compiler/test-resources/repl/errmsgs

@@ -1,85 +1,110 @@
 scala> class Inv[T](x: T)
 // defined class Inv
 scala> val x: List[String] = List(1)
--- Error:
+-- [E007] Type Mismatch Error: -------------------------------------------------
 1 | val x: List[String] = List(1)
   |                            ^
   |                            Found:    (1 : Int)
   |                            Required: String
+longer explanation available when compiling with `-explain`
+1 error found
 scala> val y: List[List[String]] = List(List(1))
--- Error:
+-- [E007] Type Mismatch Error: -------------------------------------------------
 1 | val y: List[List[String]] = List(List(1))
   |                                       ^
   |                                       Found:    (1 : Int)
   |                                       Required: String
+longer explanation available when compiling with `-explain`
+1 error found
 scala> val z: (List[String], List[Int]) = (List(1), List("a"))
--- Error:
+-- [E007] Type Mismatch Error: -------------------------------------------------
 1 | val z: (List[String], List[Int]) = (List(1), List("a"))
   |                                          ^
   |                                          Found:    (1 : Int)
   |                                          Required: String
--- Error:
+longer explanation available when compiling with `-explain`
+-- [E007] Type Mismatch Error: -------------------------------------------------
 1 | val z: (List[String], List[Int]) = (List(1), List("a"))
   |                                                   ^^^
   |                                                  Found:    ("a" : String)
   |                                                  Required: Int
+longer explanation available when compiling with `-explain`
+2 errors found
 scala> val a: Inv[String] = new Inv(new Inv(1))
--- Error:
+-- [E007] Type Mismatch Error: -------------------------------------------------
 1 | val a: Inv[String] = new Inv(new Inv(1))
   |                              ^^^^^^^^^^
   |                              Found:    Inv[Int]
   |                              Required: String
+longer explanation available when compiling with `-explain`
+1 error found
 scala> val b: Inv[String] = new Inv(1)
--- Error:
+-- [E007] Type Mismatch Error: -------------------------------------------------
 1 | val b: Inv[String] = new Inv(1)
   |                              ^
   |                              Found:    (1 : Int)
   |                              Required: String
+longer explanation available when compiling with `-explain`
+1 error found
 scala> abstract class C { type T; val x: T; val s: Unit = { type T = String; var y: T = x; locally { def f() = { type T = Int; val z: T = y }; f() } }; }
--- Error:
+-- [E007] Type Mismatch Error: -------------------------------------------------
 1 | abstract class C { type T; val x: T; val s: Unit = { type T = String; var y: T = x; locally { def f() = { type T = Int; val z: T = y }; f() } }; }
   |                                                                                  ^
   |Found:    (C.this.x : C.this.T)
   |Required: T²
   |
   |where:    T  is a type in class C
   |          T² is a type in the initializer of value s which is an alias of String
--- Error:
+longer explanation available when compiling with `-explain`
+-- [E007] Type Mismatch Error: -------------------------------------------------
 1 | abstract class C { type T; val x: T; val s: Unit = { type T = String; var y: T = x; locally { def f() = { type T = Int; val z: T = y }; f() } }; }
   |                                                                                                                                    ^
   |Found:    (y : T)
   |Required: T²
   |
   |where:    T  is a type in the initializer of value s which is an alias of String
   |          T² is a type in method f which is an alias of Int
+longer explanation available when compiling with `-explain`
+2 errors found
 scala> class Foo() { def bar: Int = 1 }; val foo = new Foo(); foo.barr
--- Error:
+-- [E008] Not Found Error: -----------------------------------------------------
 1 | class Foo() { def bar: Int = 1 }; val foo = new Foo(); foo.barr
   |                                                        ^^^^^^^^
   |                 value barr is not a member of Foo - did you mean foo.bar?
+1 error found
 scala> val x: List[Int] = "foo" :: List(1)
--- Error:
+-- [E007] Type Mismatch Error: -------------------------------------------------
 1 | val x: List[Int] = "foo" :: List(1)
   |                    ^^^^^
   |                    Found:    ("foo" : String)
   |                    Required: Int
+longer explanation available when compiling with `-explain`
+1 error found
 scala> while (((  foo ))) {}
--- Error:
+-- [E006] Not Found Error: -----------------------------------------------------
 1 | while (((  foo ))) {}
   |            ^^^
   |            Not found: foo
+longer explanation available when compiling with `-explain`
+1 error found
 scala> val a: iDontExist = 1
--- Error:
+-- [E006] Not Found Error: -----------------------------------------------------
 1 | val a: iDontExist = 1
   |        ^^^^^^^^^^
   |        Not found: type iDontExist
+longer explanation available when compiling with `-explain`
+1 error found
 scala> def foo1(x: => Int) = x _
--- Error:
+-- [E099] Syntax Error: --------------------------------------------------------
 1 | def foo1(x: => Int) = x _
   |                       ^^^
   |Only function types can be followed by _ but the current expression has type Int
+longer explanation available when compiling with `-explain`
+1 error found
 scala> def foo2(x: => Int): () => Int = x _
--- Error:
+-- [E099] Syntax Error: --------------------------------------------------------
 1 | def foo2(x: => Int): () => Int = x _
   |                                  ^^^
   |Only function types can be followed by _ but the current expression has type Int
+longer explanation available when compiling with `-explain`
+1 error found

compiler/test-resources/repl/errorThenValid

@@ -1,9 +1,10 @@
 scala> val xs = scala.collection.mutable.ListBuffer[Int]
--- Error:
+-- [E081] Type Error: ----------------------------------------------------------
 1 | val xs = scala.collection.mutable.ListBuffer[Int]
   |          ^
   |          Missing parameter type
   |
   |          I could not infer the type of the parameter elems.
+1 error found
 scala> val xs = scala.collection.mutable.ListBuffer[Int]()
 val xs: scala.collection.mutable.ListBuffer[Int] = ListBuffer()

compiler/test-resources/repl/i13208.default.scala

@@ -1,7 +1,9 @@
 scala> try 1
--- Warning:
+1 warning found
+-- [E000] Syntax Warning: ------------------------------------------------------
 1 | try 1
   | ^^^^^
   | A try without catch or finally is equivalent to putting
   | its body in a block; no exceptions are handled.
+longer explanation available when compiling with `-explain`
 val res0: Int = 1

compiler/test-resources/repl/i1370

@@ -1,5 +1,6 @@
 scala> object Lives { class Private { def foo1: Any = new Private.C1; def foo2: Any = new Private.C2 };  object Private { class C1 private {}; private class C2 {} } }
--- Error:
+-- Error: ----------------------------------------------------------------------
 1 | object Lives { class Private { def foo1: Any = new Private.C1; def foo2: Any = new Private.C2 };  object Private { class C1 private {}; private class C2 {} } }
   |                                                    ^^^^^^^^^^
   |constructor C1 cannot be accessed as a member of Lives.Private.C1 from class Private.
+1 error found

compiler/test-resources/repl/i2063

@@ -1,15 +1,21 @@
 scala> 	class Foo extends Bar // with one tab
--- Error:
+-- [E006] Not Found Error: -----------------------------------------------------
 1 | 	class Foo extends Bar // with one tab
   | 	                  ^^^
   | 	                  Not found: type Bar
+longer explanation available when compiling with `-explain`
+1 error found
 scala>                                                                               class Foo extends Bar // with spaces
--- Error:
+-- [E006] Not Found Error: -----------------------------------------------------
 1 |                                                                               class Foo extends Bar // with spaces
   |                                                                                                 ^^^
   |                                                       Not found: type Bar
+longer explanation available when compiling with `-explain`
+1 error found
 scala>                                                                                  class Foo extends Bar // with tabs
--- Error:
+-- [E006] Not Found Error: -----------------------------------------------------
 1 |                                                                                  class Foo extends Bar // with tabs
   |                                                                                                    ^^^
   |                                                       Not found: type Bar
+longer explanation available when compiling with `-explain`
+1 error found

compiler/test-resources/repl/i2213

@@ -1,10 +1,12 @@
 scala> def x
--- Error:
+-- [E019] Syntax Error: --------------------------------------------------------
 1 | def x
   |      ^
   |      Missing return type
+longer explanation available when compiling with `-explain`
 scala> def x: Int
--- Error:
+-- [E067] Syntax Error: --------------------------------------------------------
 1 | def x: Int
   |     ^
   |Declaration of method x not allowed here: only classes can have declared but undefined members
+1 error found

compiler/test-resources/repl/i2631

@@ -1,5 +1,6 @@
 scala> class Foo(x : Any) { val foo : Integer = 0; def this() = { this(foo) } }
--- Error:
+-- Error: ----------------------------------------------------------------------
 1 | class Foo(x : Any) { val foo : Integer = 0; def this() = { this(foo) } }
   |                                                                 ^^^
-  |                          foo is not accessible from constructor arguments
+  |                          foo is not accessible from constructor arguments
+1 error found

compiler/test-resources/repl/i4184

@@ -5,7 +5,8 @@ scala> object bar { class Foo }
 scala> implicit def eqFoo: CanEqual[foo.Foo, foo.Foo] = CanEqual.derived
 def eqFoo: CanEqual[foo.Foo, foo.Foo]
 scala> object Bar { new foo.Foo == new bar.Foo }
--- Error:
+-- Error: ----------------------------------------------------------------------
 1 | object Bar { new foo.Foo == new bar.Foo }
   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^
   |      Values of types foo.Foo and bar.Foo cannot be compared with == or !=
+1 error found

compiler/test-resources/repl/i4217

@@ -1,8 +1,10 @@
 scala> def foo(x: Option[Int]) = x match { case None => }
--- Warning:
+1 warning found
+-- [E029] Pattern Match Exhaustivity Warning: ----------------------------------
 1 | def foo(x: Option[Int]) = x match { case None => }
   |                           ^
   |                           match may not be exhaustive.
   |
   |                           It would fail on pattern case: Some(_)
-def foo(x: Option[Int]): Unit
+longer explanation available when compiling with `-explain`
+def foo(x: Option[Int]): Unit

compiler/test-resources/repl/i4566

@@ -1,6 +1,8 @@
 scala> object test { type ::[A, B]; def a: Int :: Int = ???; def b: Int = a }
--- Error:
+-- [E007] Type Mismatch Error: -------------------------------------------------
 1 | object test { type ::[A, B]; def a: Int :: Int = ???; def b: Int = a }
   |                                                                    ^
   |                                                      Found:    Int :: Int
   |                                                      Required: Int
+longer explanation available when compiling with `-explain`
+1 error found