From 8a28ce40a1db5dc51c4466e9fa21993b60d15310 Mon Sep 17 00:00:00 2001
From: Dale Wijnand <dale.wijnand@gmail.com>
Date: Mon, 21 Nov 2022 23:33:09 +0000
Subject: [PATCH] Fix REPL shadowing bug

---
 .../tools/dotc/printing/RefinedPrinter.scala    |  2 +-
 compiler/src/dotty/tools/dotc/typer/Typer.scala |  9 +++++++--
 .../src/dotty/tools/repl/ReplCompiler.scala     |  1 -
 .../dotty/tools/repl/ShadowingBatchTests.scala  | 14 ++++++++++++++
 .../test/dotty/tools/repl/ShadowingTests.scala  | 17 +++++++++++++++++
 5 files changed, 39 insertions(+), 4 deletions(-)

diff --git a/compiler/src/dotty/tools/dotc/printing/RefinedPrinter.scala b/compiler/src/dotty/tools/dotc/printing/RefinedPrinter.scala
index 62e1cd5baec8..568f7e271af6 100644
--- a/compiler/src/dotty/tools/dotc/printing/RefinedPrinter.scala
+++ b/compiler/src/dotty/tools/dotc/printing/RefinedPrinter.scala
@@ -1060,7 +1060,7 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
     if (sym.isImport)
       sym.infoOrCompleter match {
         case info: Namer#Completer => return info.original.show
-        case info: ImportType => return s"import $info.expr.show"
+        case info: ImportType => return s"import ${info.expr.show}"
         case _ =>
       }
     def name =
diff --git a/compiler/src/dotty/tools/dotc/typer/Typer.scala b/compiler/src/dotty/tools/dotc/typer/Typer.scala
index 032bed38482c..245bd490af20 100644
--- a/compiler/src/dotty/tools/dotc/typer/Typer.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Typer.scala
@@ -439,7 +439,13 @@ class Typer(@constructorOnly nestingLevel: Int = 0) extends Namer
               if (curImport.nn.unimported ne NoSymbol) unimported += curImport.nn.unimported
             if (curOwner.is(Package) && curImport != null && curImport.isRootImport && previous.exists)
               previous // no more conflicts possible in this case
-            else if (isPossibleImport(NamedImport) && (curImport nen outer.importInfo)) {
+            else if isPossibleImport(NamedImport) &&
+              ((curImport nen outer.importInfo)
+              || curImport != null
+                && curImport.isRootImport
+                && curImport.site.termSymbol.name.isReplWrapperName
+              )
+            then
               val namedImp = namedImportRef(curImport.uncheckedNN)
               if (namedImp.exists)
                 recurAndCheckNewOrShadowed(namedImp, NamedImport, ctx)(using outer)
@@ -456,7 +462,6 @@ class Typer(@constructorOnly nestingLevel: Int = 0) extends Namer
                 updateUnimported()
                 loop(ctx)(using outer)
               }
-            }
             else loop(ctx)(using outer)
           }
         }
diff --git a/compiler/src/dotty/tools/repl/ReplCompiler.scala b/compiler/src/dotty/tools/repl/ReplCompiler.scala
index 8db288f50aca..69bd97148d73 100644
--- a/compiler/src/dotty/tools/repl/ReplCompiler.scala
+++ b/compiler/src/dotty/tools/repl/ReplCompiler.scala
@@ -62,7 +62,6 @@ class ReplCompiler extends Compiler:
         }
 
         val rootCtx = super.rootContext.fresh
-          .setOwner(defn.EmptyPackageClass)
           .withRootImports
         (state.validObjectIndexes).foldLeft(rootCtx)((ctx, id) =>
           importPreviousRun(id)(using ctx))
diff --git a/compiler/test/dotty/tools/repl/ShadowingBatchTests.scala b/compiler/test/dotty/tools/repl/ShadowingBatchTests.scala
index 5a96976bd867..7272c10aa003 100644
--- a/compiler/test/dotty/tools/repl/ShadowingBatchTests.scala
+++ b/compiler/test/dotty/tools/repl/ShadowingBatchTests.scala
@@ -32,6 +32,20 @@ class ShadowingBatchTests extends ErrorMessagesTest:
     ictx.setSetting(classpath, classpath.value + File.pathSeparator + dir.jpath.toAbsolutePath)
   }
 
+  @Test def io =
+    val lib = """|package io.foo
+                 |
+                 |object Bar {
+                 |  def baz: Int = 42
+                 |}
+                 |""".stripMargin
+    val app = """|object Main:
+                 |  def main(args: Array[String]): Unit =
+                 |    println(io.foo.Bar.baz)
+                 |""".stripMargin
+    checkMessages(lib).expectNoErrors
+    checkMessages(app).expectNoErrors
+
   @Test def file =
     checkMessages("class C(val c: Int)").expectNoErrors
     checkMessages("object rsline1 {\n  def line1 = new C().c\n}").expect { (_, msgs) =>
diff --git a/compiler/test/dotty/tools/repl/ShadowingTests.scala b/compiler/test/dotty/tools/repl/ShadowingTests.scala
index 457819966346..98aa58a62a15 100644
--- a/compiler/test/dotty/tools/repl/ShadowingTests.scala
+++ b/compiler/test/dotty/tools/repl/ShadowingTests.scala
@@ -76,6 +76,18 @@ class ShadowingTests extends ReplTest(options = ShadowingTests.options):
     Files.delete(file)
   end compileShadowed
 
+  @Test def io = shadowedScriptedTest(name = "io",
+    shadowed = """|package io.foo
+                  |
+                  |object Bar {
+                  |  def baz: Int = 42
+                  |}
+                  |""".stripMargin,
+    script = """|scala> io.foo.Bar.baz
+                |val res0: Int = 42
+                |""".stripMargin
+  )
+
   @Test def i7635 = shadowedScriptedTest(name = "<i7635>",
     shadowed = "class C(val c: Int)",
     script =
@@ -129,6 +141,11 @@ class ShadowingTests extends ReplTest(options = ShadowingTests.options):
     ShadowingTests.createSubDir("util")
     testScript(name = "<shadow-subdir-util>",
       """|scala> import util.Try
+         |-- [E008] Not Found Error: -----------------------------------------------------
+         |1 | import util.Try
+         |  |             ^^^
+         |  |             value Try is not a member of util
+         |1 error found
          |
          |scala> object util { class Try { override def toString = "you've gotta try!" }  }
          |// defined object util