Remove extra newlines in type mismatch message

Author: smarter

compiler/src/dotty/tools/dotc/reporting/diagnostic/messages.scala

@@ -291,11 +291,10 @@ object messages {
     val kind: String = "Type Mismatch"
     val msg: String = {
       val (where, printCtx) = Formatting.disambiguateTypes(found, expected)
+      val whereSuffix = if (where.isEmpty) where else s"\n\n$where"
       val (fnd, exp) = Formatting.typeDiff(found, expected)(printCtx)
       s"""|found:    $fnd
-          |required: $exp
-          |
-          |$where""".stripMargin + whyNoMatch + implicitFailure
+          |required: $exp""".stripMargin + whereSuffix + whyNoMatch + implicitFailure
     }
 
     val explanation: String = ""

compiler/test-resources/repl/errmsgs

@@ -5,36 +5,30 @@ scala> val x: List[String] = List(1)
   |                            ^
   |                            found:    Int(1)
   |                            required: String
-  |
 scala> val y: List[List[String]] = List(List(1))
 1 | val y: List[List[String]] = List(List(1))
   |                                       ^
   |                                       found:    Int(1)
   |                                       required: String
-  |
 scala> val z: (List[String], List[Int]) = (List(1), List("a"))
 1 | val z: (List[String], List[Int]) = (List(1), List("a"))
   |                                          ^
   |                                          found:    Int(1)
   |                                          required: String
-  |
 1 | val z: (List[String], List[Int]) = (List(1), List("a"))
   |                                                   ^^^
   |                                                   found:    String("a")
   |                                                   required: Int
-  |
 scala> val a: Inv[String] = new Inv(new Inv(1))
 1 | val a: Inv[String] = new Inv(new Inv(1))
   |                              ^^^^^^^^^^
   |                              found:    Inv[Int]
   |                              required: String
-  |
 scala> val b: Inv[String] = new Inv(1)
 1 | val b: Inv[String] = new Inv(1)
   |                              ^
   |                              found:    Int(1)
   |                              required: String
-  |
 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() } }; }
 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() } }; }
   |                                                                                  ^
@@ -59,7 +53,6 @@ scala> val x: List[Int] = "foo" :: List(1)
   |                    ^^^^^
   |                    found:    String("foo")
   |                    required: Int
-  |
 scala> { def f: Int = g; val x: Int = 1; def g: Int = 5; }
 1 | { def f: Int = g; val x: Int = 1; def g: Int = 5; }
   |                ^

compiler/test-resources/repl/importFromObj

@@ -9,7 +9,6 @@ scala> buf += xs
   |        ^^
   |        found:    List[Int](o.xs)
   |        required: Int
-  |
 scala> buf ++= xs
 val res0: scala.collection.mutable.ListBuffer[Int] = ListBuffer(1, 2, 3)
 scala> import util.foo

compiler/test-resources/type-printer/type-mismatch

@@ -7,4 +7,3 @@ scala> val x: Foo[String] = res0
   |                      ^^^^
   |                      found:    Foo[Int](res0)
   |                      required: Foo[String]
-  |