Merge pull request #6066 from dotty-staging/fix-#6026

Use argument span for inlined singleton an type arguments

Author: nicolasstucki

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

@@ -211,6 +211,9 @@ class Inliner(call: tpd.Tree, rhsToInline: tpd.Tree)(implicit ctx: Context) {
    */
   private val paramBinding = new mutable.HashMap[Name, Type]
 
+  /** A map from parameter names of the inlineable method to spans of the actual arguments */
+  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`.
    */
@@ -271,12 +274,14 @@ class Inliner(call: tpd.Tree, rhsToInline: tpd.Tree)(implicit ctx: Context) {
   private def computeParamBindings(tp: Type, targs: List[Tree], argss: List[List[Tree]]): Unit = tp match {
     case tp: PolyType =>
       (tp.paramNames, targs).zipped.foreach { (name, arg) =>
+        paramSpan(name) = arg.span
         paramBinding(name) = arg.tpe.stripTypeVar
       }
       computeParamBindings(tp.resultType, Nil, argss)
     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
@@ -439,12 +444,19 @@ class Inliner(call: tpd.Tree, rhsToInline: tpd.Tree)(implicit ctx: Context) {
             case _ => tree
           }
         case tree: Ident =>
+          /* Span of the argument. Used when the argument is inlined directly without a binding */
+          def argSpan =
+            if (tree.name == nme.WILDCARD) tree.span // From type match
+            else if (tree.symbol.isTypeParam && tree.symbol.owner.isClass) tree.span // TODO is this the correct span?
+            else paramSpan(tree.name)
           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)
+              t.dealias match {
+                case tp: ConstantType => Inlined(EmptyTree, Nil, singleton(tp).withSpan(argSpan)).withSpan(tree.span)
+                case tp => singleton(tp).withSpan(argSpan)
+              }
             case Some(t) if tree.isType =>
-              TypeTree(t).withSpan(tree.span)
+              TypeTree(t).withSpan(argSpan)
             case _ => tree
           }
         case tree => tree
@@ -877,6 +889,8 @@ class Inliner(call: tpd.Tree, rhsToInline: tpd.Tree)(implicit ctx: Context) {
               case _ =>
                 false
             }
+          case Inlined(EmptyTree, Nil, ipat) =>
+            reducePattern(bindingsBuf, fromBuf, toBuf, scrut, ipat)
           case _ => false
         }
       }

tests/run/i4947a.scala renamed to tests/disabled/run/i4947a.scala

@@ -0,0 +1,14 @@
+track (i = 0): Test$.main(i4947a2.scala:4)
+track (i = 0): Test$.main(i4947a2.scala:5)
+track (i = 2): Test$.main(i4947a2.scala:4)
+track (i = 2): Test$.main(i4947a2.scala:5)
+main1 (i = -1): Test$.main(i4947a2.scala:21)
+main2 (i = -1): Test$.main(i4947a2.scala:22)
+track (i = 1): Test$.main(i4947a2.scala:4)
+track (i = 1): Test$.main(i4947a2.scala:5)
+main1 (i = -1): Test$.main(i4947a2.scala:21)
+main2 (i = -1): Test$.main(i4947a2.scala:22)
+track (i = 0): Test$.main(i4947a2.scala:4)
+track (i = 0): Test$.main(i4947a2.scala:5)
+main1 (i = -1): Test$.main(i4947a2.scala:21)
+main2 (i = -1): Test$.main(i4947a2.scala:22)

tests/run/i4947a2.check

@@ -0,0 +1,27 @@
+object Test {
+
+  inline def fact[T](inline i: Int)(f: => T): Int = {
+    printStack(i, "track")
+    printStack(i, "track")
+    f
+    if (i == 0)
+      1
+    else {
+      i * fact(i-1)(f)
+    }
+  }
+
+  def printStack(i: Int, tag: String): Unit = {
+    println(s"$tag (i = $i): ${new Exception().getStackTrace().apply(1)}")
+  }
+
+  def main(args: Array[String]): Unit = {
+    fact(0) {
+      fact(2) {
+        printStack(-1, "main1")
+        printStack(-1, "main2")
+      }
+    }
+  }
+
+}

tests/run/i4947a2.scala

@@ -1,36 +1,36 @@
-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]
+quoted_2.scala:[426..427]
 T
-quoted_2.scala:[201..202]
+quoted_2.scala:[438..444]
 scala.Predef.String
-quoted_2.scala:[201..202]
+quoted_2.scala:[455..460]
 "abc"
-quoted_2.scala:[201..202]
+quoted_2.scala:[471..472]
 U

tests/run/tasty-macro-positions.check

@@ -8,31 +8,29 @@ 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"}")
 
     type T
     type U = "abc"
 
-    fun3[T] // ERROR
-    fun3[String] // ERROR
-    fun3["abc"] // ERROR
-    fun3[U] // ERROR
+    fun3[T]
+    fun3[String]
+    fun3["abc"]
+    fun3[U]
   }
-  // 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
+
 }