Respect -deprecation flag

compiler/src/dotty/tools/dotc/reporting/Reporter.scala

@@ -50,7 +50,7 @@ trait Reporting { this: Context =>
     }
 
   def deprecationWarning(msg: => Message, pos: SourcePosition = NoSourcePosition): Unit =
-    reportWarning(new DeprecationWarning(msg, pos))
+    if (this.settings.deprecation.value) reportWarning(new DeprecationWarning(msg, pos))
 
   def migrationWarning(msg: => Message, pos: SourcePosition = NoSourcePosition): Unit =
     reportWarning(new MigrationWarning(msg, pos))

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

@@ -288,7 +288,7 @@ object Checking {
   def checkRefinementNonCyclic(refinement: Tree, refineCls: ClassSymbol, seen: mutable.Set[Symbol])
     (implicit ctx: Context): Unit = {
     def flag(what: String, tree: Tree) =
-      ctx.deprecationWarning(i"$what reference in refinement is deprecated", tree.pos)
+      ctx.warning(i"$what reference in refinement is deprecated", tree.pos)
     def forwardRef(tree: Tree) = flag("forward", tree)
     def selfRef(tree: Tree) = flag("self", tree)
     val checkTree = new TreeAccumulator[Unit] {

compiler/test/dotty/tools/dotc/CompilationTests.scala

@@ -146,6 +146,7 @@ class CompilationTests extends ParallelTesting {
     compileFilesInDir("tests/neg", defaultOptions) +
     compileFilesInDir("tests/neg-tailcall", defaultOptions) +
     compileFilesInDir("tests/neg-kind-polymorphism", defaultOptions and "-Ykind-polymorphism") +
+    compileFilesInDir("tests/neg-custom-args/deprecation", defaultOptions.and("-Xfatal-warnings", "-deprecation")) +
     compileFilesInDir("tests/neg-custom-args/fatal-warnings", defaultOptions.and("-Xfatal-warnings")) +
     compileFilesInDir("tests/neg-custom-args/allow-double-bindings", allowDoubleBindings) +
     compileDir("tests/neg-custom-args/impl-conv", defaultOptions.and("-Xfatal-warnings", "-feature")) +

tests/pos-special/fatal-warnings/deprecation.scala

@@ -0,0 +1,8 @@
+object A {
+  @deprecated("use bar instead of this one", "0.2.3")
+  def foo: Int = 3
+}
+
+object B {
+  A.foo
+}