Fix handling of lifted varargs in ElimRepeated

Fixes #15078

compiler/src/dotty/tools/dotc/transform/ElimRepeated.scala

@@ -124,17 +124,21 @@ class ElimRepeated extends MiniPhase with InfoTransformer { thisPhase =>
       tp
 
   override def transformApply(tree: Apply)(using Context): Tree =
-    val args = tree.args.mapConserve {
-      case arg: Typed if isWildcardStarArg(arg) =>
+    val args = tree.args.mapConserve { arg =>
+      if isWildcardStarArg(arg) then
+        val expr = arg match
+          case t: Typed => t.expr
+          case _ => arg // if the argument has been lifted it's not a Typed (often it's an Ident)
+
         val isJavaDefined = tree.fun.symbol.is(JavaDefined)
-        val tpe = arg.expr.tpe
         if isJavaDefined then
-          adaptToArray(arg.expr)
-        else if tpe.derivesFrom(defn.ArrayClass) then
-          arrayToSeq(arg.expr)
+          adaptToArray(expr)
+        else if expr.tpe.derivesFrom(defn.ArrayClass) then
+          arrayToSeq(expr)
         else
-          arg.expr
-      case arg => arg
+          expr
+      else
+        arg
     }
     cpy.Apply(tree)(tree.fun, args)
 
@@ -287,9 +291,9 @@ class ElimRepeated extends MiniPhase with InfoTransformer { thisPhase =>
     val array = tp.translateFromRepeated(toArray = true) // Array[? <: T]
     val element = array.elemType.hiBound // T
 
-
     if element <:< defn.AnyRefType
       || ctx.mode.is(Mode.SafeNulls) && element.stripNull <:< defn.AnyRefType
-      || element.typeSymbol.isPrimitiveValueClass then array
+      || element.typeSymbol.isPrimitiveValueClass
+    then array
     else defn.ArrayOf(TypeBounds.upper(AndType(element, defn.AnyRefType))) // Array[? <: T & AnyRef]
 }

compiler/test/dotty/tools/dotc/coverage/CoverageTests.scala

@@ -68,10 +68,11 @@ class CoverageTests:
   def computeCoverageInTmp(inputFile: Path, sourceRoot: Path, run: Boolean)(using TestGroup): Path =
     val target = Files.createTempDirectory("coverage")
     val options = defaultOptions.and("-Ycheck:instrumentCoverage", "-coverage-out", target.toString, "-sourceroot", sourceRoot.toString)
-    val test = compileFile(inputFile.toString, options)
     if run then
+      val test = compileDir(inputFile.getParent.toString, options)
       test.checkRuns()
     else
+      val test = compileFile(inputFile.toString, options)
       test.checkCompile()
     target
 

tests/coverage/run/varargs/JavaVarargs_1.java

@@ -0,0 +1,7 @@
+class JavaVarargs_1 {
+  static void method(String... args) {}
+
+  static Object multiple(Object first, String... others) {
+    return String.valueOf(first) + others.length;
+  }
+}

tests/coverage/run/varargs/test_1.check

@@ -0,0 +1,3 @@
+first0
+first0
+first3

tests/coverage/run/varargs/test_1.scala

@@ -0,0 +1,20 @@
+import java.nio.file.Files
+import java.io.File
+
+def repeated(s: String*) = ()
+
+def f(s: String) = s
+
+@main
+def Test =
+  repeated()
+  repeated(f(""), "b")
+  JavaVarargs_1.method()
+  JavaVarargs_1.method("")
+
+  var m = JavaVarargs_1.multiple("first")
+  println(m)
+  m = JavaVarargs_1.multiple(f("first"))
+  println(m)
+  m = JavaVarargs_1.multiple(f("first"), "a", "b", "c")
+  println(m)

tests/coverage/run/varargs/test_1.scoverage.check

@@ -0,0 +1,293 @@
+# Coverage data, format version: 3.0
+# Statement data:
+# - id
+# - source path
+# - package name
+# - class name
+# - class type (Class, Object or Trait)
+# - full class name
+# - method name
+# - start offset
+# - end offset
+# - line number
+# - symbol name
+# - tree name
+# - is branch
+# - invocations count
+# - is ignored
+# - description (can be multi-line)
+# '' sign
+# ------------------------------------------
+0
+varargs/test_1.scala
+<empty>
+test_1$package$
+Object
+<empty>.test_1$package$
+repeated
+48
+60
+3
+repeated
+DefDef
+false
+0
+false
+def repeated
+
+1
+varargs/test_1.scala
+<empty>
+test_1$package$
+Object
+<empty>.test_1$package$
+f
+79
+84
+5
+f
+DefDef
+false
+0
+false
+def f
+
+2
+varargs/test_1.scala
+<empty>
+test_1$package$
+Object
+<empty>.test_1$package$
+Test
+120
+130
+9
+repeated
+Apply
+false
+0
+false
+repeated()
+
+3
+varargs/test_1.scala
+<empty>
+test_1$package$
+Object
+<empty>.test_1$package$
+Test
+142
+147
+10
+f
+Apply
+false
+0
+false
+f("")
+
+4
+varargs/test_1.scala
+<empty>
+test_1$package$
+Object
+<empty>.test_1$package$
+Test
+133
+153
+10
+repeated
+Apply
+false
+0
+false
+repeated(f(""), "b")
+
+5
+varargs/test_1.scala
+<empty>
+test_1$package$
+Object
+<empty>.test_1$package$
+Test
+156
+178
+11
+method
+Apply
+false
+0
+false
+JavaVarargs_1.method()
+
+6
+varargs/test_1.scala
+<empty>
+test_1$package$
+Object
+<empty>.test_1$package$
+Test
+181
+205
+12
+method
+Apply
+false
+0
+false
+JavaVarargs_1.method("")
+
+7
+varargs/test_1.scala
+<empty>
+test_1$package$
+Object
+<empty>.test_1$package$
+Test
+217
+248
+14
+multiple
+Apply
+false
+0
+false
+JavaVarargs_1.multiple("first")
+
+8
+varargs/test_1.scala
+<empty>
+test_1$package$
+Object
+<empty>.test_1$package$
+Test
+251
+261
+15
+println
+Apply
+false
+0
+false
+println(m)
+
+9
+varargs/test_1.scala
+<empty>
+test_1$package$
+Object
+<empty>.test_1$package$
+Test
+291
+301
+16
+f
+Apply
+false
+0
+false
+f("first")
+
+10
+varargs/test_1.scala
+<empty>
+test_1$package$
+Object
+<empty>.test_1$package$
+Test
+268
+302
+16
+multiple
+Apply
+false
+0
+false
+JavaVarargs_1.multiple(f("first"))
+
+11
+varargs/test_1.scala
+<empty>
+test_1$package$
+Object
+<empty>.test_1$package$
+Test
+305
+315
+17
+println
+Apply
+false
+0
+false
+println(m)
+
+12
+varargs/test_1.scala
+<empty>
+test_1$package$
+Object
+<empty>.test_1$package$
+Test
+345
+355
+18
+f
+Apply
+false
+0
+false
+f("first")
+
+13
+varargs/test_1.scala
+<empty>
+test_1$package$
+Object
+<empty>.test_1$package$
+Test
+322
+371
+18
+multiple
+Apply
+false
+0
+false
+JavaVarargs_1.multiple(f("first"), "a", "b", "c")
+
+14
+varargs/test_1.scala
+<empty>
+test_1$package$
+Object
+<empty>.test_1$package$
+Test
+374
+384
+19
+println
+Apply
+false
+0
+false
+println(m)
+
+15
+varargs/test_1.scala
+<empty>
+test_1$package$
+Object
+<empty>.test_1$package$
+Test
+101
+115
+8
+Test
+DefDef
+false
+0
+false
+@main
+def Test
+