Fix #11555: In REPL, render string values inside quotes

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

@@ -106,24 +106,25 @@ private[repl] class Rendering(parentClassLoader: Option[ClassLoader] = None) {
    *
    *  Calling this method evaluates the expression using reflection
    */
-  private def valueOf(sym: Symbol)(using Context): Option[String] = {
+  private def valueOf(sym: Symbol)(using Context): Option[String] =
+    if !sym.is(Flags.Method) && sym.info == defn.UnitType
+    then return None
+
     val objectName = sym.owner.fullName.encode.toString.stripSuffix("$")
     val resObj: Class[?] = Class.forName(objectName, true, classLoader())
-    val value =
-      resObj
-        .getDeclaredMethods.find(_.getName == sym.name.encode.toString)
-        .map(_.invoke(null))
-    val string = value.map(replStringOf(_))
-    if (!sym.is(Flags.Method) && sym.info == defn.UnitType)
-      None
-    else
-      string.map { s =>
-        if (s.startsWith(str.REPL_SESSION_LINE))
-          s.drop(str.REPL_SESSION_LINE.length).dropWhile(c => c.isDigit || c == '$')
-        else
-          s
-      }
-  }
+
+    resObj.getDeclaredMethods.find(_.getName == sym.name.encode.toString).map { method =>
+      val value = method.invoke(null)
+      val resultType = method.getReturnType()
+      val rawStringRepr = replStringOf(value)
+      val stringRepr =
+        if rawStringRepr.startsWith(str.REPL_SESSION_LINE)
+        then rawStringRepr.drop(str.REPL_SESSION_LINE.length).dropWhile(c => c.isDigit || c == '$')
+        else rawStringRepr
+
+      if resultType == classOf[String] then s""""$stringRepr"""" else stringRepr
+    }
+  end valueOf
 
   /** Formats errors using the `messageRenderer` */
   def formatError(dia: Diagnostic)(implicit state: State): Diagnostic =

compiler/test-resources/repl/i1369

@@ -1,4 +1,4 @@
 scala> print("foo")
 foo
 scala> "Hello"
-val res0: String = Hello
+val res0: String = "Hello"

compiler/test/dotty/tools/repl/ReplCompilerTests.scala

@@ -196,7 +196,7 @@ class ReplCompilerTests extends ReplTest {
 
   @Test def testSingletonPrint = fromInitialState { implicit state =>
     run("""val a = "hello"; val x: a.type = a""")
-    assertMultiLineEquals("val a: String = hello\nval x: a.type = hello", storedOutput().trim)
+    assertMultiLineEquals("val a: String = \"hello\"\nval x: a.type = \"hello\"", storedOutput().trim)
   }
 
   @Test def i6574 = fromInitialState { implicit state =>

language-server/test/dotty/tools/languageserver/WorksheetTest.scala

@@ -84,13 +84,13 @@ class WorksheetTest {
         ((m1 to m2), s"1${nl}2${nl}3"))
   }
 
-  @Test def patternMatching0: Unit = {
+  @Test def   : Unit = {
     ws"""${m1}1 + 2 match {
           case x if x % 2 == 0 => "even"
           case _ => "odd"
         }${m2}""".withSource
       .run(m1,
-        ((m1 to m2), "val res0: String = odd"))
+        ((m1 to m2), "val res0: String = \"odd\""))
   }
 
   @Test def patternMatching1: Unit = {

staging/test-resources/repl-staging/i6007

@@ -5,6 +5,6 @@ def compiler: quoted.staging.Compiler
 scala> def v(using Quotes) = '{ (if true then Some(1) else None).map(v => v+1) }
 def v(using x$1: quoted.Quotes): quoted.Expr[Option[Int]]
 scala> scala.quoted.staging.withQuotes(v.show)
-val res0: String = (if (true) scala.Some.apply[scala.Int](1) else scala.None).map[scala.Int](((v: scala.Int) => v.+(1)))
+val res0: String = "(if (true) scala.Some.apply[scala.Int](1) else scala.None).map[scala.Int](((v: scala.Int) => v.+(1)))"
 scala> scala.quoted.staging.run(v)
 val res1: Option[Int] = Some(2)