Fix #8866: Inline calls inserted by macros

Author: nicolasstucki

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

@@ -1233,7 +1233,8 @@ 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/run-macros/beta-reduce-inline-result.check

@@ -1,4 +1,4 @@
-compile-time: ((3.+(1): scala.Int): scala.Int)
+compile-time: ((4: scala.Int): scala.Int)
 run-time: 4
 compile-time: ((1: 1): scala.Int)
 run-time: 1