Fix #8866: Inline calls inserted by macros

Author: nicolasstucki

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

@@ -1237,7 +1237,8 @@ class Inliner(call: tpd.Tree, rhsToInline: tpd.Tree)(using Context) {
         case res: Apply if res.symbol == defn.InternalQuoted_exprSplice
                         && level == 0
                         && !suppressInline =>
-          expandMacro(res.args.head, tree.span)
+          val expanded = expandMacro(res.args.head, tree.span)
+          typedExpr(expanded) // Inline calls and constant fold code generated by the macro
         case res => res
       }
 

tests/pos-macros/i8866/Macro_1.scala

@@ -0,0 +1,27 @@
+import scala.quoted._
+
+object OtherMacro {
+
+  def impl(using qctx: QuoteContext): Expr[Int] =
+    '{ 42 }
+
+  inline def apply = ${ OtherMacro.impl }
+
+}
+
+object Macro {
+
+  def impl(using qctx: QuoteContext): Expr[Int] = {
+    import qctx.tasty._
+
+    let(
+      Select.unique(
+        '{ OtherMacro }.unseal,
+        "apply"
+      )
+    )(identity).seal.cast[Int]
+  }
+
+  inline def apply = ${ Macro.impl }
+
+}

tests/pos-macros/i8866/Test_2.scala

@@ -0,0 +1 @@
+val a = Macro.apply

tests/pos-macros/i8866b/Macro_1.scala

@@ -0,0 +1,23 @@
+import scala.quoted._
+
+object Other {
+  inline def apply = 5
+}
+
+object Macro {
+
+  def impl(using qctx: QuoteContext): Expr[Int] = {
+    import qctx.tasty._
+
+    let(
+      Select.unique(
+        '{ Other }.unseal,
+        "apply"
+      )
+    )(identity).seal.cast[Int]
+
+  }
+
+  inline def apply = ${ Macro.impl }
+
+}

tests/pos-macros/i8866b/Test_2.scala

@@ -0,0 +1 @@
+val a = Macro.apply

tests/pos-macros/i8866c/Macro_1.scala

@@ -0,0 +1,12 @@
+import scala.quoted._
+
+def f(xs: Boolean*): Unit = ???
+
+def mcrImpl(using QuoteContext): Expr[Unit] =
+  val func: Expr[Seq[Boolean] => Unit] =
+    '{(esx: Seq[Boolean]) => f(esx: _*)}
+  val trees: Expr[Seq[Boolean]] = '{Seq(true)}
+  Expr.betaReduce('{ $func($trees) })
+end mcrImpl
+
+inline def mcr: Unit = ${ mcrImpl }

tests/pos-macros/i8866c/Test_2.scala

@@ -0,0 +1 @@
+val x = mcr

tests/pos-macros/i9687/Macro_1.scala

@@ -0,0 +1,44 @@
+package x
+
+import scala.quoted._
+
+object FastPath {
+
+  inline def sum(x:Int):Int =
+    x + 1
+
+}
+
+object SlowPath {
+
+  def sum(x:Int):Int =
+    x + 1
+
+}
+
+object X {
+
+ inline def transform[A](inline x:A):A = ${
+    transformImpl[A]('x)
+ }
+
+ def transformImpl[A:Type](x:Expr[A])(using qctx: QuoteContext):Expr[A] = {
+    import qctx.tasty._
+    val slowPath = '{ SlowPath }.unseal
+    val fastPath = '{ FastPath }.unseal
+    val transformer = new TreeMap() {
+      override def transformTerm(term:Term)(using ctx:Context):Term = {
+        term match
+          case Apply(sel@Select(o,m),args) =>
+                if ( o.tpe =:= slowPath.tpe && m=="sum" )
+                   Apply(Select.unique(fastPath,"sum"), args)
+                else
+                   super.transformTerm(term)
+          case _ => super.transformTerm(term)
+      }
+    }
+    val r = transformer.transformTerm(x.unseal).seal.cast[A]
+    println(s"result: ${r.show}")
+    r
+ }
+}

tests/pos-macros/i9687/Test_2.scala

@@ -0,0 +1,12 @@
+package x
+
+
+object Main {
+
+
+ def main(args:Array[String]):Unit =
+   val r = X.transform{
+     SlowPath.sum(1)
+   }
+
+}