Don't check features when retyping

Fixes #14637

Author: odersky

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

@@ -1408,6 +1408,7 @@ trait ReChecking extends Checking {
   override def checkNoModuleClash(sym: Symbol)(using Context) = ()
   override def checkCanThrow(tp: Type, span: Span)(using Context): Unit = ()
   override def checkCatch(pat: Tree, guard: Tree)(using Context): Unit = ()
+  override def checkFeature(name: TermName, description: => String, featureUseSite: Symbol, pos: SrcPos)(using Context): Unit = ()
 }
 
 trait NoChecking extends ReChecking {
@@ -1430,5 +1431,4 @@ trait NoChecking extends ReChecking {
   override def checkMembersOK(tp: Type, pos: SrcPos)(using Context): Type = tp
   override def checkInInlineContext(what: String, pos: SrcPos)(using Context): Unit = ()
   override def checkValidInfix(tree: untpd.InfixOp, meth: Symbol)(using Context): Unit = ()
-  override def checkFeature(name: TermName, description: => String, featureUseSite: Symbol, pos: SrcPos)(using Context): Unit = ()
 }

tests/pos-special/fatal-warnings/i14637.scala

@@ -0,0 +1,6 @@
+class C
+
+object Givens:
+  given cOrdering: Ordering[C] with
+    override def compare(c0: C, c1: C) = 0
+  val greeting = "we love Givens"