Merge pull request #1078 from dotty-staging/fix-#324

Better handling enclosing class computations

Author: smarter

src/dotty/tools/dotc/typer/Implicits.scala

@@ -402,7 +402,8 @@ trait Implicits { self: Typer =>
         || (to isRef defn.ObjectClass)
         || (to isRef defn.UnitClass)
         || (from.tpe isRef defn.NothingClass)
-        || (from.tpe isRef defn.NullClass)) NoImplicitMatches
+        || (from.tpe isRef defn.NullClass)
+        || (from.tpe eq NoPrefix)) NoImplicitMatches
     else
       try inferImplicit(to.stripTypeVar.widenExpr, from, from.pos)
       catch {

src/dotty/tools/dotc/typer/TypeAssigner.scala

@@ -8,6 +8,7 @@ import Scopes._, Contexts._, Constants._, Types._, Symbols._, Names._, Flags._,
 import ErrorReporting._, Annotations._, Denotations._, SymDenotations._, StdNames._, TypeErasure._
 import util.Positions._
 import config.Printers._
+import NameOps._
 
 trait TypeAssigner {
   import tpd._
@@ -16,7 +17,11 @@ trait TypeAssigner {
    *  @param packageOk   The qualifier may refer to a package.
    */
   def qualifyingClass(tree: untpd.Tree, qual: Name, packageOK: Boolean)(implicit ctx: Context): Symbol = {
-    def qualifies(sym: Symbol) = sym.isClass && (qual.isEmpty || sym.name == qual)
+    def qualifies(sym: Symbol) =
+      sym.isClass && (
+          qual.isEmpty ||
+          sym.name == qual ||
+          sym.is(Module) && sym.name.stripModuleClassSuffix == qual)
     ctx.outersIterator.map(_.owner).find(qualifies) match {
       case Some(c) if packageOK || !(c is Package) =>
         c

test/dotc/tests.scala

@@ -155,6 +155,7 @@ class tests extends CompilerTest {
   @Test def neg_i0091_infpaths = compileFile(negDir, "i0091-infpaths", xerrors = 3)
   @Test def neg_i0248_inherit_refined = compileFile(negDir, "i0248-inherit-refined", xerrors = 4)
   @Test def neg_i0281 = compileFile(negDir, "i0281-null-primitive-conforms", xerrors = 3)
+  @Test def neg_i324 = compileFile(negDir, "i324", xerrors = 2)
   @Test def neg_i583 = compileFile(negDir, "i0583-skolemize", xerrors = 2)
   @Test def neg_i941 = compileFile(negDir, "i941", xerrors = 3)
   @Test def neg_finalSealed = compileFile(negDir, "final-sealed", xerrors = 2)

tests/neg/i324.scala

@@ -0,0 +1,5 @@
+class O
+object O {
+   val x: this.type = OO.this
+   val y: O = OO.this
+}

tests/pos/i324.scala

@@ -0,0 +1,7 @@
+class O
+object O {
+   val x: this.type = O.this
+}
+object O2 {
+   val x: this.type = O2.this
+}