Test case for REPL bad symbolic reference

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

@@ -409,6 +409,20 @@ class ReplCompilerTests extends ReplTest:
   @Test def `i13097 expect template after colon` = contextually:
     assert(ParseResult.isIncomplete("class C:"))
 
+  @Test def i15562: Unit = initially {
+    val s1 = run("List(1, 2).filter(_ % 2 == 0).foreach(println)")
+    assertEquals("2", storedOutput().trim)
+    s1
+  } andThen { s1 ?=>
+    val comp = tabComplete("List(1, 2).filter(_ % 2 == 0).fore")
+    assertEquals(List("foreach"), comp.distinct)
+    s1
+  } andThen {
+    val s2 = run("List(1, 2).filter(_ % 2 == 0).foreach(println)")
+    assertEquals("2", storedOutput().trim)
+    s2
+  }
+
 object ReplCompilerTests:
 
   private val pattern = Pattern.compile("\\r[\\n]?|\\n");

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

@@ -40,6 +40,10 @@ extends ReplDriver(options, new PrintStream(out, true, StandardCharsets.UTF_8.na
 
   def contextually[A](op: Context ?=> A): A = op(using initialState.context)
 
+  /** Returns the `(<instance completions>, <companion completions>)`*/
+  def tabComplete(src: String)(implicit state: State): List[String] =
+    completions(src.length, src, state).map(_.value).sorted
+
   extension [A](state: State)
     infix def andThen(op: State ?=> A): A = op(using state)
 

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

@@ -8,10 +8,6 @@ import org.junit.Test
 /** These tests test input that has proved problematic */
 class TabcompleteTests extends ReplTest {
 
-  /** Returns the `(<instance completions>, <companion completions>)`*/
-  private def tabComplete(src: String)(implicit state: State): List[String] =
-    completions(src.length, src, state).map(_.value).sorted
-
   @Test def tabCompleteList = initially {
     val comp = tabComplete("List.r")
     assertEquals(List("range"), comp.distinct)