Merge pull request #12099 from dotty-staging/fix-#9531

Add regression test

Author: nicolasstucki

compiler/src/dotty/tools/dotc/ast/Desugar.scala

@@ -946,7 +946,7 @@ object desugar {
       tree.withMods(mods)
     else if tree.name.startsWith("$") && !tree.isBackquoted then
       report.error(
-        """Quoted pattern variable names starting with $ are not suported anymore.
+        """Quoted pattern variable names starting with $ are not supported anymore.
           |Use lower cases type pattern name instead.
           |""".stripMargin,
         tree.srcPos)

tests/pos/i9531.scala

@@ -0,0 +1,10 @@
+trait Scope:
+  type Expr[+T]
+
+def exprQuote[T](x: T)(using s: Scope, dummy: Null = null): s.Expr[T] = ???
+def exprQuote[T <: Singleton](x: T)(using s: Scope): s.Expr[T] = ???
+
+def test(using s: Scope): Unit =
+  val t1: s.Expr[1] = exprQuote(1)
+  val t2 = exprQuote(1)
+  val t3: s.Expr[1] = t2