Fix#12600: Handle ExprType during tab completion

compiler/src/dotty/tools/dotc/interactive/Completion.scala

@@ -300,7 +300,8 @@ object Completion {
               case name: TermName if include(denot, name) => Some((denot, name))
               case _ => None
 
-        types.flatMap { tpe =>
+        types.flatMap { tp =>
+          val tpe = tp.widenExpr
           tpe.membersBasedOnFlags(required = ExtensionMethod, excluded = EmptyFlags)
             .collect { case DenotWithMatchingName(denot, name) => TermRef(tpe, denot.symbol) -> name }
         }

compiler/test/dotty/tools/repl/TabcompleteTests.scala

@@ -132,4 +132,10 @@ class TabcompleteTests extends ReplTest {
   @Test def i6415 = fromInitialState { implicit s =>
     assertEquals(List("Predef"), tabComplete("object Foo { opaque type T = Pre"))
   }
+
+  @Test def i12600 = fromInitialState { implicit s =>
+    assertEquals(List("select", "show", "simplified"),
+      tabComplete("import quoted.* ; def fooImpl(using Quotes): Expr[Int] = { import quotes.reflect.* ; TypeRepr.of[Int].s"))
+  }
+
 }

language-server/test/dotty/tools/languageserver/CompletionTest.scala

@@ -842,4 +842,19 @@ class CompletionTest {
           |object Main { "abc".xx${m1} }""".withSource
       .completion(m1, Set())
   }
+
+  @Test def i13365: Unit = {
+    code"""|import scala.quoted._
+        |
+        |object Test {
+        |  def test(using Quotes)(str: String) = {
+        |    import quotes.reflect._
+        |    val msg = Expr(str)
+        |    val printHello = '{ print("sdsd") }
+        |    val tree = printHello.asTerm
+        |    tree.sh${m1}
+        |  }
+        |}""".withSource
+      .completion(m1, Set(("show",Method, "(using x$2: x$1.reflect.Printer[x$1.reflect.Tree]): String")))
+  }
 }