Fix scala#6026: Use argument position for singleton arguments

Author: nicolasstucki

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

@@ -211,6 +211,8 @@ class Inliner(call: tpd.Tree, rhsToInline: tpd.Tree)(implicit ctx: Context) {
    */
   private val paramBinding = new mutable.HashMap[Name, Type]
 
+  private val paramSpan = new mutable.HashMap[Name, Span]
+
   /** A map from references to (type and value) parameters of the inlineable method
    *  to their corresponding argument or proxy references, as given by `paramBinding`.
    */
@@ -277,6 +279,7 @@ class Inliner(call: tpd.Tree, rhsToInline: tpd.Tree)(implicit ctx: Context) {
     case tp: MethodType =>
       assert(argss.nonEmpty, i"missing bindings: $tp in $call")
       (tp.paramNames, tp.paramInfos, argss.head).zipped.foreach { (name, paramtp, arg) =>
+        paramSpan(name) = arg.span
         paramBinding(name) = arg.tpe.dealias match {
           case _: SingletonType if isIdempotentExpr(arg) => arg.tpe
           case _ => paramBindingDef(name, paramtp, arg, bindingsBuf).symbol.termRef
@@ -441,8 +444,7 @@ class Inliner(call: tpd.Tree, rhsToInline: tpd.Tree)(implicit ctx: Context) {
         case tree: Ident =>
           paramProxy.get(tree.tpe) match {
             case Some(t) if tree.isTerm && t.isSingleton =>
-              // FIXME wrong span, this is the span inside the inline method
-              singleton(t.dealias).withSpan(tree.span)
+              singleton(t.dealias).withSpan(paramSpan(tree.name))
             case Some(t) if tree.isType =>
               TypeTree(t).withSpan(tree.span)
             case _ => tree

tests/run/tasty-macro-positions.check

@@ -1,30 +1,30 @@
-quoted_2.scala:[103..103]
+quoted_2.scala:[173..174]
 a
-quoted_2.scala:[103..103]
+quoted_2.scala:[184..185]
 b
-quoted_2.scala:[213..214]
+quoted_2.scala:[195..196]
 c
-quoted_2.scala:[224..225]
+quoted_2.scala:[206..207]
 d
-quoted_2.scala:[103..103]
+quoted_2.scala:[217..222]
 "abc"
-quoted_2.scala:[259..272]
+quoted_2.scala:[232..245]
 ("abc": scala.Predef.String)
-quoted_2.scala:[282..296]
+quoted_2.scala:[255..269]
 _root_.scala.StringContext.apply(("abc", "": scala.<repeated>[scala#Predef.String])).s(("def": scala.<repeated>[scala.Any]))
-quoted_2.scala:[154..154]
+quoted_2.scala:[281..282]
 a
-quoted_2.scala:[154..154]
+quoted_2.scala:[293..294]
 b
-quoted_2.scala:[350..351]
+quoted_2.scala:[305..306]
 c
-quoted_2.scala:[362..363]
+quoted_2.scala:[317..318]
 d
-quoted_2.scala:[154..154]
+quoted_2.scala:[329..334]
 "abc"
-quoted_2.scala:[399..412]
+quoted_2.scala:[345..358]
 ("abc": scala.Predef.String)
-quoted_2.scala:[423..437]
+quoted_2.scala:[369..383]
 _root_.scala.StringContext.apply(("abc", "": scala.<repeated>[scala#Predef.String])).s(("def": scala.<repeated>[scala.Any]))
 quoted_2.scala:[201..202]
 T

tests/run/tasty-macro-positions/quoted_2.scala

@@ -8,19 +8,19 @@ object Test {
     def c: String = "abc"
     def d: 42 = 42
 
-    fun(a) // ERROR
-    fun(b) // ERROR
+    fun(a)
+    fun(b)
     fun(c)
     fun(d)
-    fun("abc") // ERROR
+    fun("abc")
     fun("abc": String)
     fun(s"abc${"def"}")
 
-    fun2(a) // ERROR
-    fun2(b) // ERROR
+    fun2(a)
+    fun2(b)
     fun2(c)
     fun2(d)
-    fun2("abc") // ERROR
+    fun2("abc")
     fun2("abc": String)
     fun2(s"abc${"def"}")
 
@@ -33,6 +33,6 @@ object Test {
     fun3[U] // ERROR
   }
   // FIXME all the lines marked as ERROR have the wrong position on the three of the argument.
-  // they all have as source file this file but the span of `'x` in `fun` or `fun2`.
-  // see #6026 and #6027
+  // they all have as source file this file but the span of `'[T]` in `fun3`.
+  // see #6027
 }