Fix scala#4801: WIP

Author: nicolasstucki

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

@@ -2,10 +2,15 @@ package dotty.tools.dotc
 package transform
 
 import core._
-import Decorators._, Flags._, Types._, Contexts._, Symbols._, Constants._
+import Decorators._
+import Flags._
+import Types._
+import Contexts._
+import Symbols._
+import Constants._
 import Flags._
 import ast.Trees._
-import ast.{TreeTypeMap, untpd}
+import ast.{TreeTypeMap, tpd, untpd}
 import util.Positions._
 import tasty.TreePickler.Hole
 import SymUtils._
@@ -120,12 +125,19 @@ class ReifyQuotes extends MacroTransformWithImplicits {
       new Reifier(isQuote, this, if (isQuote) level + 1 else level - 1, levels, nestedEmbedded)
     }
 
+    def inlined: Reifier = {
+      assert(level == 0)
+      new Reifier(true, this, 0, levels, embedded)
+    }
+
     /** We are in a `~(...)` context that is not shadowed by a nested `'(...)` */
     def inSplice: Boolean = outer != null && !inQuote
 
     /** We are not in a `~(...)` or a `'(...)` */
     def isRoot: Boolean = outer == null
 
+    def isInlined: Boolean = inQuote && level == 0
+
     /** A map from type ref T to expressions of type `quoted.Type[T]`".
      *  These will be turned into splices using `addTags` and represent type variables
      *  that can be possibly healed.
@@ -422,10 +434,27 @@ class ReifyQuotes extends MacroTransformWithImplicits {
         spliceOutsideQuotes(splice.pos)
         splice
       }
-      else {
+      else if (level > 0) {
         val (body1, quotes) = nested(isQuote = false).split(splice.qualifier)
         makeHole(body1, quotes, splice.tpe).withPos(splice.pos)
       }
+      else if (isInlined) {
+        // FIXME
+        val evaluatedSplice = Splicer.splice(splice.qualifier, splice.qualifier.pos, macroClassLoader).withPos(splice.qualifier.pos)
+        if (ctx.reporter.hasErrors) EmptyTree
+        else transform(evaluatedSplice)
+      } else {
+        if (!Splicer.canBeSpliced(splice.qualifier))
+          ctx.error( // TODO adapt error message
+            """Malformed inline macro.
+              |
+              |Expected the ~ to be at the top of the RHS:
+              |  inline def foo(x: X, ..., y: Y): Int = ~impl(x, ... '(y))
+              |
+              |The contents of the splice must call a static method. Arguments must be quoted or inlined.
+            """.stripMargin, splice.pos)
+        splice
+      }
     }
 
     /** Transforms the contents of a nested splice
@@ -550,37 +579,10 @@ class ReifyQuotes extends MacroTransformWithImplicits {
             val last = enteredSyms
             stats.foreach(markDef)
             mapOverTree(last)
-          case Inlined(call, bindings, InlineSplice(spliced)) =>
-            val tree2 =
-              if (level == 0) {
-                val evaluatedSplice = Splicer.splice(spliced, tree.pos, macroClassLoader).withPos(tree.pos)
-                if (ctx.reporter.hasErrors) EmptyTree
-                else transform(cpy.Inlined(tree)(call, bindings, evaluatedSplice))
-              }
-              else super.transform(tree)
-
-            // due to value-discarding which converts an { e } into { e; () })
-            if (tree.tpe =:= defn.UnitType) Block(tree2 :: Nil, Literal(Constant(())))
-            else tree2
+          case tree: Inlined if !isInlined && level == 0 =>
+            inlined.transform(tree)
           case _: Import =>
             tree
-          case tree: DefDef if tree.symbol.is(Macro) && level == 0 =>
-            markDef(tree)
-            tree.rhs match {
-              case InlineSplice(_) =>
-                mapOverTree(enteredSyms) // Ignore output, only check PCP
-                cpy.DefDef(tree)(rhs = defaultValue(tree.rhs.tpe))
-              case _ =>
-                ctx.error(
-                  """Malformed inline macro.
-                    |
-                    |Expected the ~ to be at the top of the RHS:
-                    |  inline def foo(x: X, ..., y: Y): Int = ~impl(x, ... '(y))
-                    |
-                    |The contents of the splice must call a static method. Arguments must be quoted or inlined.
-                  """.stripMargin, tree.rhs.pos)
-                EmptyTree
-            }
           case _ =>
             markDef(tree)
             checkLevel(mapOverTree(enteredSyms))

tests/neg/i4433.scala

@@ -1,7 +1,7 @@
 
 object Foo {
-  inline def g(inline p: Int => Boolean): Boolean = ~{ // error
-    if(p(5)) '(true)
+  inline def g(inline p: Int => Boolean): Boolean = ~{
+    if(p(5)) '(true) // error
     else '(false)
   }
 }

tests/neg/quote-macro-splice.scala

@@ -2,22 +2,22 @@ import scala.quoted._
 
 object Test {
 
-  inline def foo1: Int = { // error
+  inline def foo1: Int = {
     println()
-    ~impl(1.toExpr)
+    ~impl(1.toExpr) // error
   }
 
-  inline def foo2: Int = { // error
-    ~impl(1.toExpr)
-    ~impl(2.toExpr)
+  inline def foo2: Int = {
+    ~impl(1.toExpr) // error
+    ~impl(2.toExpr) // error
   }
 
-  inline def foo3: Int = { // error
+  inline def foo3: Int = {
     val a = 1
     ~impl('(a))
   }
 
-  inline def foo4: Int = { // error
+  inline def foo4: Int = {
     ~impl('(1))
     1
   }

tests/run/i4801/Macros_1.scala

@@ -0,0 +1,11 @@
+import scala.quoted._
+
+object Macro {
+
+  inline def foo(b: Boolean): Int = {
+    if (b) ~bar(true)
+    else ~bar(false)
+  }
+
+  def bar(b: Boolean): Expr[Int] = if (b) '(1) else '(0)
+}

tests/run/i4801/Test_2.scala

@@ -0,0 +1,8 @@
+object Test {
+  def main(args: Array[String]): Unit = {
+//    println(Macro.foo(true))
+//    println(Macro.foo(false))
+    val x: Boolean = true
+    println(Macro.foo(x))
+  }
+}