Merge pull request #14117 from dotty-staging/fix-#12225

Check for splices in quoted macro parameters

Author: anatoliykmetyuk

compiler/src/dotty/tools/dotc/transform/Splicer.scala

@@ -149,7 +149,14 @@ object Splicer {
         case Typed(expr, _) => checkIfValidArgument(expr)
 
         case Apply(Select(Apply(fn, quoted :: Nil), nme.apply), _) if fn.symbol == defn.QuotedRuntime_exprQuote =>
-          // OK
+          val noSpliceChecker = new TreeTraverser {
+            def traverse(tree: Tree)(using Context): Unit = tree match
+              case Spliced(_) =>
+                report.error("Quoted argument of macros may not have splices", tree.srcPos)
+              case _ =>
+                traverseChildren(tree)
+          }
+          noSpliceChecker.traverse(quoted)
 
         case Apply(TypeApply(fn, List(quoted)), _)if fn.symbol == defn.QuotedTypeModule_of =>
           // OK

tests/neg-macros/i12225.scala

@@ -0,0 +1,7 @@
+object TestMacro {
+  inline def test[T](inline t: T): T = ${ identity('{ identity(${ identity('{ identity(${ identity('t) }) }) }) }) } // error
+}
+
+object Test {
+  TestMacro.test("x")
+}