See through static calls on inner objects

Author: liufengyun

compiler/src/dotty/tools/dotc/transform/init/Checking.scala

@@ -95,6 +95,10 @@ object Checking {
     && (obj.enclosingClass == state.thisClass
         || obj.appearsInside(state.thisClass) && state.superConstrCalled)
 
+  /** Whether the obj is directly nested inside the current class */
+  private def isNestedObject(obj: Global)(using state: State): Boolean =
+    obj.symbol.owner == state.thisClass
+
 // ------- checking construtor ---------------------------
 
   /** Check that the given concrete class may be initialized safely
@@ -257,6 +261,9 @@ object Checking {
         val target = resolve(obj.moduleClass, sym)
         if isObjectAccessSafe(obj) then
           check(MethodCall(ThisRef()(obj.source), target)(eff.source))
+        else if isNestedObject(obj) then
+          val pot = FieldReturn(ThisRef()(obj.source), obj.symbol)(obj.source)
+          check(MethodCall(pot, target)(eff.source))
         else
           state.dependencies += StaticCall(obj.moduleClass, target)(state.path)
           Errors.empty

tests/init/neg/global-cycle12.scala

@@ -0,0 +1,24 @@
+// from Scala.js
+object Names {
+  private final val ConstructorSimpleEncodedName: String =
+    "<init>"
+
+  final class SimpleMethodName(encoded: String)
+
+  object SimpleMethodName {
+    def apply(name: String): SimpleMethodName =
+      val res = name == ConstructorSimpleEncodedName
+      new SimpleMethodName(name)
+  }
+
+  val ConstructorSimpleName: SimpleMethodName =
+    SimpleMethodName(ConstructorSimpleEncodedName)
+}
+
+object A {              // error
+  val n: Int = B.m
+}
+
+object B {
+  val m: Int = A.n
+}

tests/init/neg/t3273.check

@@ -2,21 +2,21 @@
 4 |  val num1: LazyList[Int] = 1 #:: num1.map(_ + 1)                        // error
   |                                  ^^^^^^^^^^^^^^^
   |             Promoting the value to fully-initialized is unsafe.
-  |              Calling trace:
+  |              Calling trace (full):
   |              -> val num1: LazyList[Int] = 1 #:: num1.map(_ + 1)                        // error	[ t3273.scala:4 ]
   |
   |             The unsafe promotion may cause the following problem(s):
   |
-  |             1. Access non-initialized value num1. Calling trace:
+  |             1. Access non-initialized value num1. Calling trace (full):
   |              -> val num1: LazyList[Int] = 1 #:: num1.map(_ + 1)                        // error	[ t3273.scala:4 ]
 -- Error: tests/init/neg/t3273.scala:5:61 ------------------------------------------------------------------------------
 5 |  val num2: LazyList[Int] = 1 #:: num2.iterator.map(_ + 1).to(LazyList)  // error
   |                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |             Promoting the value to fully-initialized is unsafe.
-  |              Calling trace:
+  |              Calling trace (full):
   |              -> val num2: LazyList[Int] = 1 #:: num2.iterator.map(_ + 1).to(LazyList)  // error	[ t3273.scala:5 ]
   |
   |             The unsafe promotion may cause the following problem(s):
   |
-  |             1. Access non-initialized value num2. Calling trace:
+  |             1. Access non-initialized value num2. Calling trace (full):
   |              -> val num2: LazyList[Int] = 1 #:: num2.iterator.map(_ + 1).to(LazyList)  // error	[ t3273.scala:5 ]