Merge pull request #1289 from retronym/ticket/6276-2

Avoid spurious warning for `def foo = x.foo`.

3 files changed, 33 insertions, 7 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
index f1f2794a95..d515934c58 100644
--- a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
@@ -1208,11 +1208,16 @@ abstract class RefChecks extends InfoTransform with reflect.internal.transform.R
 
     // SI-6276 warn for `def foo = foo` or `val bar: X = bar`, which come up more frequently than you might think.
     def checkInfiniteLoop(valOrDef: ValOrDefDef) {
+      def callsSelf = valOrDef.rhs match {
+        case t @ (Ident(_) | Select(This(_), _)) =>
+          t hasSymbolWhich (_.accessedOrSelf == valOrDef.symbol)
+        case _ => false
+      }
       val trivialInifiniteLoop = (
         !valOrDef.isErroneous
      && !valOrDef.symbol.isValueParameter
      && valOrDef.symbol.paramss.isEmpty
-     && valOrDef.rhs.hasSymbolWhich(_.accessedOrSelf == valOrDef.symbol)
+     && callsSelf
       )
       if (trivialInifiniteLoop)
         unit.warning(valOrDef.rhs.pos, s"${valOrDef.symbol.fullLocationString} does nothing other than call itself recursively")
diff --git a/test/files/neg/t6276.check b/test/files/neg/t6276.check
index 8bd92cf293..0b3dfa5531 100644
--- a/test/files/neg/t6276.check
+++ b/test/files/neg/t6276.check
@@ -1,13 +1,19 @@
-t6276.scala:4: error: method a does nothing other than call itself recursively
+t6276.scala:4: error: method a in class C does nothing other than call itself recursively
       def a: Any = a // warn
                    ^
-t6276.scala:5: error: value b does nothing other than call itself recursively
+t6276.scala:5: error: value b in class C does nothing other than call itself recursively
       val b: Any = b // warn
                    ^
-t6276.scala:10: error: method a does nothing other than call itself recursively
+t6276.scala:7: error: method c in class C does nothing other than call itself recursively
+      def c: Any = this.c // warn
+                        ^
+t6276.scala:8: error: method d in class C does nothing other than call itself recursively
+      def d: Any = C.this.d // warn
+                          ^
+t6276.scala:13: error: method a does nothing other than call itself recursively
       def a: Any = a // warn
                    ^
-t6276.scala:19: error: method a does nothing other than call itself recursively
+t6276.scala:22: error: method a does nothing other than call itself recursively
       def a = a // warn
               ^
-four errors found
+6 errors found
diff --git a/test/files/neg/t6276.scala b/test/files/neg/t6276.scala
index 8333618964..bd0a473f71 100644
--- a/test/files/neg/t6276.scala
+++ b/test/files/neg/t6276.scala
@@ -1,8 +1,11 @@
 object Test {
   def foo(a: Int, b: Int, c: Int) {
-    new {
+    class C {
       def a: Any = a // warn
       val b: Any = b // warn
+
+      def c: Any = this.c // warn
+      def d: Any = C.this.d // warn
     }
 
     def method {
@@ -25,5 +28,17 @@ object Test {
       val b: Any = {println(""); b}
       def c(i: Int): Any = c(i - 0)
     }
+
+    class D {
+      def other: D = null
+      def foo: Any = other.foo
+    }
+
+    class E {
+      def foo: Any = 0
+      class D extends E {
+        override def foo: Any = E.this.foo
+      }
+    }
   }
 }