Macro inlining fails for trivial functions #556
Description
There is a bug with the macro inlining code. The following gives: 3
object Demo extends App {
val res: Int = Macros.test(1, 2)
println(res)
}
object Macros {
def test(a: Int, b: Int): Int = macro test_impl
def test_impl(c: Context)(a: c.Expr[Int], b: c.Expr[Int]): c.Expr[Int] = {
import c.universe._
val tree: Tree = q"$a + $b"
new InlineUtil[c.type](c).inlineAndReset[Int](tree)
}
}
which is correct. But if the macro is changed as follows, the result is 2
object Macros {
def test(a: Int, b: Int): Int = macro test_impl
def test_impl(c: Context)(a: c.Expr[Int], b: c.Expr[Int]): c.Expr[Int] = {
import c.universe._
val fn = c.universe.reify((i: Int, j: Int) => i + j)
val tree: Tree = q"$fn($a, $b)"
new InlineUtil[c.type](c).inlineAndReset[Int](tree)
}
}
The worst part of it is that there is no warning. I checked the code, but my macro debugging capabilities are limited. It looks as if the error originates from values being overwritten in InlineSymbol.transform(...). Apparently, several instances of tree are supplied to transform(tree: Tree) where the tree.symbol == symbol match is ambiguous.