Fix readLine in TestREPL to align with Ammonite reader

Needs to read several input lines at once.

Enables repl test of new error messages.

Author: odersky

src/dotty/tools/dotc/repl/REPL.scala

@@ -50,7 +50,7 @@ class REPL extends Driver {
 object REPL {
   class Config {
     val prompt             = "scala> "
-    val continuationPrompt = "     | "
+    val continuationPrompt = "       "
     val version            = ".next (pre-alpha)"
 
     def context(ctx: Context): Context = ctx

test/test/TestREPL.scala

@@ -24,12 +24,20 @@ class TestREPL(script: String) extends REPL {
       ctx.fresh.setSetting(ctx.settings.color, "never")
 
     override def input(in: Interpreter)(implicit ctx: Context) = new InteractiveReader {
-      val lines = script.lines
+      val lines = script.lines.buffered
       def readLine(prompt: String): String = {
         val line = lines.next
-        if (line.startsWith(prompt) || line.startsWith(continuationPrompt)) {
+        val buf = new StringBuilder
+        if (line.startsWith(prompt)) {
           output.println(line)
-          line.drop(prompt.length)
+          buf append line.drop(prompt.length)
+          while (lines.hasNext && lines.head.startsWith(continuationPrompt)) {
+            val continued = lines.next
+            output.println(continued)
+            buf append "\n"
+            buf append continued.drop(continuationPrompt.length)
+          }
+          buf.toString
         }
         else readLine(prompt)
       }

tests/repl/errmsgs.check

@@ -0,0 +1,74 @@
+scala> class Inv[T](x: T)
+defined class Inv
+scala> val x: List[String] = List(1)
+<console>:4: error: type mismatch:
+ found   : Int(1)
+ required: String
+val x: List[String] = List(1)
+                           ^
+scala> val y: List[List[String]] = List(List(1))
+<console>:4: error: type mismatch:
+ found   : Int(1)
+ required: String
+val y: List[List[String]] = List(List(1))
+                                      ^
+scala> val z: (List[String], List[Int]) = (List(1), List("a"))
+<console>:4: error: type mismatch:
+ found   : Int(1)
+ required: String
+val z: (List[String], List[Int]) = (List(1), List("a"))
+                                         ^
+<console>:4: error: type mismatch:
+ found   : String("a")
+ required: Int
+val z: (List[String], List[Int]) = (List(1), List("a"))
+                                                  ^
+scala> val a: Inv[String] = new Inv(new Inv(1))
+<console>:5: error: type mismatch:
+ found   : Inv[T]
+ required: String
+
+where  T  is a type variable with constraint >: Int(1)
+
+val a: Inv[String] = new Inv(new Inv(1))
+                                 ^
+scala> val b: Inv[String] = new Inv(1)
+<console>:5: error: type mismatch:
+ found   : Int(1)
+ required: String
+val b: Inv[String] = new Inv(1)
+                             ^
+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()
+             }
+           }
+         }
+<console>:9: error: type mismatch:
+ found   : C.this.T(C.this.x)
+ required: T'
+
+where  T   is a type in class C
+       T'  is a type in the initalizer of value s which is an alias of String
+
+      var y: T = x
+                 ^
+<console>:13: error: type mismatch:
+ found   : T(y)
+ required: T'
+
+where  T   is a type in the initalizer of value s which is an alias of String
+       T'  is a type in method f which is an alias of Int
+
+          val z: T = y
+                     ^
+scala> :quit