Merge pull request #4052 from dotty-staging/add-quote-show-tree-cleaner

Add quote.show tree cleaner

Author: nicolasstucki

compiler/src/dotty/tools/dotc/quoted/QuoteDriver.scala

@@ -44,7 +44,8 @@ class QuoteDriver extends Driver {
     def show(tree: Tree, ctx: Context): String = {
       val printer = new DecompilerPrinter(ctx)
       val pageWidth = ctx.settings.pageWidth.value(ctx)
-      printer.toText(tree).mkString(pageWidth, false)
+      val tree1 = if (settings.rawTree) tree else (new TreeCleaner).transform(tree)(ctx)
+      printer.toText(tree1).mkString(pageWidth, false)
     }
     withTree(expr, show, settings)
   }

compiler/src/dotty/tools/dotc/quoted/Toolbox.scala

@@ -53,7 +53,7 @@ object Toolbox {
 
   }
 
-  class Settings[T] private (val outDir: Option[String], val compilerArgs: List[String])
+  class Settings[T] private (val outDir: Option[String], val rawTree: Boolean, val compilerArgs: List[String])
 
   object Settings {
 
@@ -69,19 +69,22 @@ object Toolbox {
         ): Settings[Run] = {
       var compilerArgs1 = compilerArgs
       if (optimise) compilerArgs1 = "-optimise" :: compilerArgs1
-      new Settings(outDir, compilerArgs1)
+      new Settings(outDir, false, compilerArgs1)
     }
 
     /** Quote show settings
+     *  @param color Print output with colors
+     *  @param rawTree Do not remove quote tree artifacts
      *  @param compilerArgs Compiler arguments. Use only if you know what you are doing.
      */
     def show(
         color: Boolean = false,
+        rawTree: Boolean = false,
         compilerArgs: List[String] = Nil
         ): Settings[Show] = {
       var compilerArgs1 = compilerArgs
       compilerArgs1 = s"-color:${if (color) "always" else "never"}" :: compilerArgs1
-      new Settings(None, compilerArgs1)
+      new Settings(None, rawTree, compilerArgs1)
     }
 
   }

compiler/src/dotty/tools/dotc/quoted/TreeCleaner.scala

@@ -0,0 +1,46 @@
+package dotty.tools.dotc.quoted
+
+import dotty.tools.dotc.ast.Trees._
+import dotty.tools.dotc.ast.tpd
+import dotty.tools.dotc.core.Contexts._
+import dotty.tools.dotc.core.Constants._
+import dotty.tools.dotc.core.Symbols._
+import dotty.tools.dotc.core.Types._
+
+/** Clean up quote artifacts from the tree to make it simpler to read.
+ *  - Flattens block and remove blocks with not statements
+ *  - Inline type aliases in the tree
+ */
+class TreeCleaner extends tpd.TreeMap {
+  import tpd._
+
+  /** List of symbols and their types for type aliases `type T = U` */
+  private[this] var aliasesSyms: List[Symbol] = Nil
+  private[this] var aliasesTypes: List[Type] = Nil
+
+  override def transform(tree: Tree)(implicit ctx: Context): Tree = {
+    val tree0 = tree match {
+      case TypeDef(_, TypeBoundsTree(lo, hi)) if lo == hi =>
+        aliasesSyms = tree.symbol :: aliasesSyms
+        aliasesTypes = lo.tpe :: aliasesTypes
+        Literal(Constant(()))
+      case _ => tree
+    }
+
+    super.transform(tree0) match {
+      case Block(Nil, expr1) => expr1
+      case Block(stats1, expr1) =>
+        val flatStats = stats1.flatMap {
+          case Block(stats2, expr2) => stats2 ::: expr2 :: Nil
+          case Literal(Constant(())) => Nil
+          case stat => stat :: Nil
+        }
+        expr1 match {
+          case Block(stats3, expr3) => Block(flatStats ::: stats3, expr3)
+          case expr3 => Block(flatStats, expr3)
+        }
+      case tree1: TypeTree => TypeTree(tree1.tpe.subst(aliasesSyms, aliasesTypes))
+      case tree1 => tree1
+    }
+  }
+}

tests/run-with-compiler/i3823-c.check

@@ -1,7 +1,4 @@
 {
-  type T = Int
-  {
-    val z: T = 2
-    ()
-  }
+  val z: Int = 2
+  ()
 }

tests/run-with-compiler/i3876-b.check

@@ -1,8 +1,6 @@
 6
 {
   val x$1: Int = 3
-  {
-    def f(x: Int): Int = x.+(x)
-    f(x$1)
-  }
+  def f(x: Int): Int = x.+(x)
+  f(x$1)
 }

tests/run-with-compiler/i3876-c.check

@@ -1,16 +1,14 @@
 6
 {
   val x$1: Int = 3
-  {
-    val f: 
-      Function1[Int, Int] 
-        {
-          def apply(x: Int): Int
-        }
-     = 
+  val f: 
+    Function1[Int, Int] 
       {
-        (x: Int) => x.+(x)
+        def apply(x: Int): Int
       }
-    (f: (x: Int) => Int).apply(x$1)
-  }
+   = 
+    {
+      (x: Int) => x.+(x)
+    }
+  (f: (x: Int) => Int).apply(x$1)
 }

tests/run-with-compiler/i3876.check

@@ -1,7 +1,5 @@
 6
 {
   val x$1: Int = 3
-  {
-    x$1.+(x$1)
-  }
+  x$1.+(x$1)
 }

tests/run-with-compiler/quote-run-2.check

@@ -1,18 +1,12 @@
 1.0
 5.0
 {
+  val y: Double = 5.0.*(5.0)
+  y
+}
+5.0.*(
   {
     val y: Double = 5.0.*(5.0)
     y
   }
-}
-{
-  5.0.*(
-    {
-      {
-        val y: Double = 5.0.*(5.0)
-        y
-      }
-    }
-  )
-}
+)

tests/run-with-compiler/quote-run-constants-extract-1.check

@@ -0,0 +1,5 @@
+3
+4
+abc
+null
+OK

tests/run-with-compiler/quote-run-constants-extract-1.scala

@@ -0,0 +1,15 @@
+import scala.quoted._
+
+import dotty.tools.dotc.quoted.Toolbox._
+
+object Test {
+
+  def main(args: Array[String]): Unit = {
+    (3: Expr[Int]) match { case Constant(n) => println(n) }
+    '(4) match { case Constant(n) => println(n) }
+    '("abc") match { case Constant(n) => println(n) }
+    '(null) match { case Constant(n) => println(n) }
+
+    '(new Object) match { case Constant(n) => println(n); case _ => println("OK") }
+  }
+}