Fix #9342: Use semantic name for inline bindings

Author: nicolasstucki

compiler/src/dotty/tools/dotc/core/NameKinds.scala

@@ -295,7 +295,7 @@ object NameKinds {
   val DocArtifactName: UniqueNameKind        = new UniqueNameKind("$doc")
   val UniqueInlineName: UniqueNameKind       = new UniqueNameKind("$i")
   val InlineScrutineeName: UniqueNameKind    = new UniqueNameKind("$scrutinee")
-  val InlineBinderName: UniqueNameKind       = new UniqueNameKind("$elem")
+  val InlineBinderName: UniqueNameKind       = new UniqueNameKind("$")
 
   /** A kind of unique extension methods; Unlike other unique names, these can be
    *  unmangled.

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

@@ -421,7 +421,7 @@ class Inliner(call: tpd.Tree, rhsToInline: tpd.Tree)(using Context) {
     val (bindingFlags, bindingType) =
       if (isByName) (inlineFlags, ExprType(argtpe.widen))
       else (inlineFlags, argtpe.widen)
-    val boundSym = newSym(name, bindingFlags, bindingType).asTerm
+    val boundSym = newSym(InlineBinderName.fresh(name.asTermName), bindingFlags, bindingType).asTerm
     val binding = {
       if (isByName) DefDef(boundSym, arg.changeOwner(ctx.owner, boundSym))
       else ValDef(boundSym, arg)

tests/pos/i9342a.scala

@@ -0,0 +1,3 @@
+inline def label(x: Int, inline g: Int => String): String = g(x)
+def f: Int => String = ???
+def label2(g: Int) = label(g, f)

tests/pos/i9342b.scala

@@ -0,0 +1,10 @@
+trait Label[A]:
+  def apply(v: A): String
+
+given [A] as Label[A] = _.toString
+
+extension [A](x: A) inline def label(using inline l: Label[A]): String = l(x)
+
+def label1[A](v: A) = v.label
+
+def label2[A](l: A) = l.label

tests/pos/i9342c.scala

@@ -0,0 +1,9 @@
+trait Label[A]:
+  def apply(v: A): String
+
+def g[A]: Label[A] = _.toString
+
+inline def label[A](x: A, inline l: Label[A]): String = l(x)
+
+def label1[A](v: A) = label(v, g)
+def label2[A](l: A) = label(l, g)

tests/run-macros/quote-inline-function.check

@@ -4,12 +4,12 @@ Normal function
   val j: scala.Int = 5
   while (i.<(j)) {
     val x$1: scala.Int = i
-    f.apply(x$1)
+    f$1.apply(x$1)
     i = i.+(1)
   }
   while ({
     val x$2: scala.Int = i
-    f.apply(x$2)
+    f$1.apply(x$2)
     i = i.+(1)
     i.<(j)
   }) ()
@@ -21,12 +21,12 @@ By name function
   val j: scala.Int = 5
   while (i.<(j)) {
     val x$3: scala.Int = i
-    f.apply(x$3)
+    f$2.apply(x$3)
     i = i.+(1)
   }
   while ({
     val x$4: scala.Int = i
-    f.apply(x$4)
+    f$2.apply(x$4)
     i = i.+(1)
     i.<(j)
   }) ()

tests/run-macros/quote-matching-optimize-1.check

@@ -18,15 +18,15 @@ Result: ()
 
 Original: scala.List.apply[scala.Int](1, 2, 3).map[scala.Int](((a: scala.Int) => a.*(2))).map[java.lang.String](((b: scala.Int) => b.toString()))
 Optimized: scala.List.apply[scala.Int](1, 2, 3).map[java.lang.String](((x: scala.Int) => {
-  val x$1: scala.Int = x.*(2)
-  x$1.toString()
+  val x$6: scala.Int = x.*(2)
+  x$6.toString()
 }))
 Result: List(2, 4, 6)
 
 Original: scala.List.apply[scala.Int](55, 67, 87).map[scala.Char](((a: scala.Int) => a.toChar)).map[java.lang.String](((b: scala.Char) => b.toString()))
 Optimized: scala.List.apply[scala.Int](55, 67, 87).map[java.lang.String](((x: scala.Int) => {
-  val x$2: scala.Char = x.toChar
-  x$2.toString()
+  val x$8: scala.Char = x.toChar
+  x$8.toString()
 }))
 Result: List(7, C, W)
 

tests/run-macros/quote-matching-optimize-2.check

@@ -18,15 +18,15 @@ Result: ()
 
 Original: ls.map[scala.Int](((a: scala.Int) => a.*(2))).map[java.lang.String](((b: scala.Int) => b.toString()))
 Optimized: ls.map[java.lang.String](((x: scala.Int) => {
-  val x$1: scala.Int = x.*(2)
-  x$1.toString()
+  val x$6: scala.Int = x.*(2)
+  x$6.toString()
 }))
 Result: List(2, 4, 6)
 
 Original: ls.map[scala.Char](((a: scala.Int) => a.toChar)).map[java.lang.String](((b: scala.Char) => b.toString()))
 Optimized: ls.map[java.lang.String](((x: scala.Int) => {
-  val x$2: scala.Char = x.toChar
-  x$2.toString()
+  val x$8: scala.Char = x.toChar
+  x$8.toString()
 }))
 Result: List(
, , )
 

tests/run-macros/quoted-matching-docs.check

@@ -2,5 +2,5 @@
 6
 10.+(Test.a)
 15
-args.sum[scala.Int](scala.math.Numeric.IntIsIntegral)
+args$5.sum[scala.Int](scala.math.Numeric.IntIsIntegral)
 9

tests/run-macros/tasty-argument-tree-1.check

@@ -5,7 +5,7 @@ tree deref. vals: Literal(Constant(3))
 tree: Inlined(None, Nil, Ident("v"))
 tree deref. vals: Literal(Constant(1))
 
-tree: Inlined(None, Nil, Ident("x"))
+tree: Inlined(None, Nil, Ident("x$1"))
 tree deref. vals: Literal(Constant(2))
 
 tree: Inlined(None, Nil, Ident("l"))
@@ -14,29 +14,29 @@ tree deref. vals: Literal(Constant(3))
 tree: Inlined(None, Nil, Ident("a"))
 tree deref. vals: Ident("a")
 
-tree: Inlined(None, Nil, Ident("x"))
+tree: Inlined(None, Nil, Ident("x$2"))
 tree deref. vals: Ident("b")
 
-tree: Inlined(None, Nil, Ident("x"))
+tree: Inlined(None, Nil, Ident("x$3"))
 tree deref. vals: Apply(Ident("d2"), Nil)
 
-tree: Inlined(None, Nil, Ident("x"))
+tree: Inlined(None, Nil, Ident("x$4"))
 tree deref. vals: Apply(Ident("d3"), List(Literal(Constant(3))))
 
-tree: Inlined(None, Nil, Ident("x"))
+tree: Inlined(None, Nil, Ident("x$5"))
 tree deref. vals: TypeApply(Ident("d4"), List(TypeIdent("Int")))
 
 tree: Inlined(None, Nil, Ident("vv"))
 tree deref. vals: Literal(Constant(1))
 
-tree: Inlined(None, Nil, Ident("x"))
+tree: Inlined(None, Nil, Ident("x$6"))
 tree deref. vals: Literal(Constant(1))
 
 tree: Inlined(None, Nil, Ident("vd"))
 tree deref. vals: Literal(Constant(2))
 
-tree: Inlined(None, Nil, Ident("x"))
+tree: Inlined(None, Nil, Ident("x$7"))
 tree deref. vals: Literal(Constant(2))
 
-tree: Inlined(None, Nil, Ident("x"))
+tree: Inlined(None, Nil, Ident("x$8"))
 tree deref. vals: Apply(TypeApply(Select(Ident("Tuple2"), "apply"), List(Inferred(), Inferred())), List(Literal(Constant(1)), Literal(Constant(2))))