Fix #4754: Don't generate inline accessor for constants

Author: allanrenucci

compiler/src/dotty/tools/dotc/transform/PostTyper.scala

@@ -17,7 +17,7 @@ object PostTyper {
 
 /** A macro transform that runs immediately after typer and that performs the following functions:
  *
- *  (1) Add super accessors and protected accessors (@see SuperAccessors)
+ *  (1) Add super accessors (@see SuperAccessors)
  *
  *  (2) Convert parameter fields that have the same name as a corresponding
  *      public parameter field in a superclass to a forwarder to the superclass

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

@@ -48,13 +48,16 @@ object Inliner {
       def accessorNameKind = InlineAccessorName
 
       /** A definition needs an accessor if it is private, protected, or qualified private
-        *  and it is not part of the tree that gets inlined. The latter test is implemented
-        *  by excluding all symbols properly contained in the inlined method.
-        */
+       *  and it is not part of the tree that gets inlined. The latter test is implemented
+       *  by excluding all symbols properly contained in the inlined method.
+       *
+       *  Constant vals don't need accessors since they are inlined in FirstTransform.
+       */
       def needsAccessor(sym: Symbol)(implicit ctx: Context) =
         sym.isTerm &&
         (sym.is(AccessFlags) || sym.privateWithin.exists) &&
-        !sym.isContainedIn(inlineSym)
+        !sym.isContainedIn(inlineSym) &&
+        !(sym.isStable && sym.info.widenTermRefExpr.isInstanceOf[ConstantType])
 
       def preTransform(tree: Tree)(implicit ctx: Context): Tree
 

tests/pos/i4754.scala

@@ -0,0 +1,13 @@
+object Foo {
+  private final val x = 1
+  private def y = 2
+}
+
+class Foo {
+  import Foo._
+  inline def foo = x + Foo.x + y + Foo.y
+}
+
+class Test {
+  (new Foo).foo
+}