Fix #6530: Only cancel term quotes with term splices (and vice versa)

Author: nicolasstucki

compiler/src/dotty/tools/dotc/typer/Typer.scala

@@ -1949,9 +1949,12 @@ class Typer extends Namer
    */
   def typedQuote(tree: untpd.Quote, pt: Type)(implicit ctx: Context): Tree = track("typedQuote") {
     tree.quoted match {
-      case untpd.Splice(innerExpr) =>
+      case untpd.Splice(innerExpr) if tree.isTerm =>
         ctx.warning("Canceled splice directly inside a quote. '{ ${ XYZ } } is equivalent to XYZ.", tree.sourcePos)
         typed(innerExpr, pt)
+      case untpd.TypSplice(innerType) if tree.isType =>
+        ctx.warning("Canceled splice directly inside a quote. '[ ${ XYZ } ] is equivalent to XYZ.", tree.sourcePos)
+        typed(innerType, pt)
       case quoted if quoted.isType =>
         ctx.compilationUnit.needsStaging = true
         typedTypeApply(untpd.TypeApply(untpd.ref(defn.InternalQuoted_typeQuoteR), quoted :: Nil), pt)(quoteContext).withSpan(tree.span)
@@ -2027,7 +2030,7 @@ class Typer extends Namer
   def typedSplice(tree: untpd.Splice, pt: Type)(implicit ctx: Context): Tree = track("typedSplice") {
     checkSpliceOutsideQuote(tree)
     tree.expr match {
-      case untpd.Quote(innerExpr) =>
+      case untpd.Quote(innerExpr) if innerExpr.isTerm =>
         ctx.warning("Canceled quote directly inside a splice. ${ '{ XYZ } } is equivalent to XYZ.", tree.sourcePos)
         typed(innerExpr, pt)
       case expr =>
@@ -2062,7 +2065,13 @@ class Typer extends Namer
   def typedTypSplice(tree: untpd.TypSplice, pt: Type)(implicit ctx: Context): Tree = track("typedTypSplice") {
     ctx.compilationUnit.needsStaging = true
     checkSpliceOutsideQuote(tree)
-    typedSelect(untpd.Select(tree.expr, tpnme.splice), pt)(spliceContext).withSpan(tree.span)
+    tree.expr match {
+      case untpd.Quote(innerType) if innerType.isType =>
+        ctx.warning("Canceled quote directly inside a splice. ${ '[ XYZ ] } is equivalent to XYZ.", tree.sourcePos)
+        typed(innerType, pt)
+      case expr =>
+        typedSelect(untpd.Select(tree.expr, tpnme.splice), pt)(spliceContext).withSpan(tree.span)
+    }
   }
 
   private def checkSpliceOutsideQuote(tree: untpd.Tree)(implicit ctx: Context): Unit = {

tests/neg/i6530.check

@@ -0,0 +1,5 @@
+-- [E007] Type Mismatch Error: tests/neg/i6530.scala:2:26 --------------------------------------------------------------
+2 |  inline def q : Int = ${ '[ Int ] } // error
+  |                          ^^^^^^^^
+  |                          Found:    quoted.Type[Int]
+  |                          Required: quoted.Expr[Int]

tests/neg/i6530.scala

@@ -0,0 +1,4 @@
+object Macros {
+  inline def q : Int = ${ '[ Int ] } // error
+  val x : Int = 1 + q
+}

tests/neg/i6530b.scala

@@ -0,0 +1,11 @@
+object Foo {
+  val program = '{
+    val tpe: quoted.Type[Int] = ???
+    val expr: quoted.Expr[Int] = ???
+
+    val a: quoted.Expr[Int] = ${ '[Int] } // error
+    val b: quoted.Expr[Int] = '{ $tpe } // error
+    val c: ${ '{ 43 } } = ???  // error
+    val d: quoted.Type[Int] = '[ $expr ] // error
+  }
+}