Merge pull request #5891 from dotty-staging/fix-#5890

Fix #5890: Handle trees with only empty statements in REPL

Author: nicolasstucki

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

@@ -103,7 +103,7 @@ class ReplCompiler extends Compiler {
     Definitions(
       defs.toList,
       state.copy(
-        objectIndex = state.objectIndex + (if (defs.isEmpty) 0 else 1),
+        objectIndex = state.objectIndex + 1,
         valIndex = valIdx
       )
     )
@@ -123,29 +123,27 @@ class ReplCompiler extends Compiler {
    *  }
    *  ```
    */
-  private def wrapped(defs: Definitions, objectTermName: TermName): untpd.PackageDef = {
+  private def wrapped(defs: Definitions, objectTermName: TermName, span: Span): untpd.PackageDef = {
     import untpd._
 
-    assert(defs.stats.nonEmpty)
-
     implicit val ctx: Context = defs.state.context
 
     val tmpl = Template(emptyConstructor, Nil, Nil, EmptyValDef, defs.stats)
     val module = ModuleDef(objectTermName, tmpl)
-      .withSpan(Span(0, defs.stats.last.span.end))
+      .withSpan(span)
 
     PackageDef(Ident(nme.EMPTY_PACKAGE), List(module))
   }
 
-  private def createUnit(defs: Definitions)(implicit ctx: Context): CompilationUnit = {
+  private def createUnit(defs: Definitions, span: Span)(implicit ctx: Context): CompilationUnit = {
     val objectName = ctx.source.file.toString
     assert(objectName.startsWith(str.REPL_SESSION_LINE))
     assert(objectName.endsWith(defs.state.objectIndex.toString))
     val objectTermName = ctx.source.file.toString.toTermName
     objectNames.update(defs.state.objectIndex, objectTermName)
 
     val unit = CompilationUnit(ctx.source)
-    unit.untpdTree = wrapped(defs, objectTermName)
+    unit.untpdTree = wrapped(defs, objectTermName, span)
     unit
   }
 
@@ -158,8 +156,9 @@ class ReplCompiler extends Compiler {
   }
 
   final def compile(parsed: Parsed)(implicit state: State): Result[(CompilationUnit, State)] = {
+    assert(!parsed.trees.isEmpty)
     val defs = definitions(parsed.trees, state)
-    val unit = createUnit(defs)(state.context)
+    val unit = createUnit(defs, Span(0, parsed.trees.last.span.end))(state.context)
     runCompilationUnit(unit, defs.state)
   }
 

compiler/test-resources/repl/i5890

@@ -0,0 +1,12 @@
+scala>
+
+scala> {}
+
+scala> {};{}
+
+scala> {{}}
+
+scala> {()}
+
+scala> ()
+