Fix #7944: Only treat erased as a keyword under -Yerased-terms

Author: nicolasstucki

compiler/src/dotty/tools/dotc/parsing/Scanners.scala

@@ -202,7 +202,8 @@ object Scanners {
     private val commentBuf = new mutable.StringBuilder
 
     private def handleMigration(keyword: Token): Token =
-      if (!isScala2CompatMode) keyword
+      if (keyword == ERASED && !ctx.settings.YerasedTerms.value) IDENTIFIER
+      else if (!isScala2CompatMode) keyword
       else if (scala3keywords.contains(keyword)) treatAsIdent()
       else keyword
 

tests/pos/i7944.scala

@@ -0,0 +1,8 @@
+package hello
+
+object HelloWorld {
+  def main(args: Array[String]): Unit =
+    println(erased(5))
+
+  def erased(x: Int): Any = x
+}