Consider static and non-static methods as non-double def

[Cherry-picked e873376]

Author: dwijnand

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

@@ -1125,7 +1125,8 @@ trait Checking {
         def javaFieldMethodPair =
           decl.is(JavaDefined) && other.is(JavaDefined) &&
           decl.is(Method) != other.is(Method)
-        if (decl.matches(other) && !javaFieldMethodPair) {
+        def staticNonStaticPair = decl.isScalaStatic != other.isScalaStatic
+        if (decl.matches(other) && !javaFieldMethodPair && !staticNonStaticPair) {
           def doubleDefError(decl: Symbol, other: Symbol): Unit =
             if (!decl.info.isErroneous && !other.info.isErroneous)
               report.error(DoubleDefinition(decl, other, cls), decl.srcPos)

tests/run/19394.scala

@@ -0,0 +1,21 @@
+import scala.annotation.{ static, targetName }
+
+class Foo
+object Foo:
+  @static def foo: String = "foo"
+  @targetName("foo") def fooBincompat: String = foo
+
+class Bar
+object Bar:
+  @static def bar: String = "bar"
+  def bar: String = bar
+
+object Test:
+  def main(args: Array[String]): Unit =
+    assert(Foo.foo == "foo")
+    assert(classOf[Foo].getMethod("foo").invoke(null) == "foo") // static
+    assert(Foo.getClass.getMethod("foo").invoke(Foo) == "foo") // instance, on module class
+
+    assert(Bar.bar == "bar")
+    assert(classOf[Bar].getMethod("bar").invoke(null) == "bar")
+    assert(Bar.getClass.getMethod("bar").invoke(Bar) == "bar")