Add workaroud missing positions in case clases from tasty

Author: nicolasstucki

compiler/src/dotty/tools/dotc/CompilationUnit.scala

@@ -19,6 +19,8 @@ class CompilationUnit(val source: SourceFile) {
 
   def isJava = source.file.name.endsWith(".java")
 
+  def isFromTasty = untpdTree.isEmpty
+
   /** Pickled TASTY binaries, indexed by class. */
   var pickled: Map[ClassSymbol, Array[Byte]] = Map()
 }

compiler/src/dotty/tools/dotc/typer/Typer.scala

@@ -58,9 +58,11 @@ object Typer {
   }
 
   /** Assert tree has a position, unless it is empty or a typed splice */
-  def assertPositioned(tree: untpd.Tree)(implicit ctx: Context) =
-    if (!tree.isEmpty && !tree.isInstanceOf[untpd.TypedSplice] && ctx.typerState.isGlobalCommittable)
+  def assertPositioned(tree: untpd.Tree)(implicit ctx: Context) = {
+    def fromTasty = ctx.compilationUnit.isFromTasty // FIXME missing positions when loading from tasty
+    if (!tree.isEmpty && !tree.isInstanceOf[untpd.TypedSplice] && ctx.typerState.isGlobalCommittable && !fromTasty)
       assert(tree.pos.exists, s"position not set for $tree # ${tree.uniqueId}")
+  }
 
   private val ExprOwner = new Property.Key[Symbol]
   private val InsertedApply = new Property.Key[Unit]

tests/pos-from-tasty/simpleCaseClass0.scala

@@ -0,0 +1,3 @@
+package foo
+
+case class Foo()

tests/pos-from-tasty/simpleCaseClass1.scala

@@ -0,0 +1,3 @@
+package foo
+
+case class Foo(a: Int)

tests/pos-from-tasty/simpleCaseClass2.scala

@@ -0,0 +1,4 @@
+package foo
+
+case class Bar(a: Int)
+object Bar