Backport "Fix Closure span assignment in makeClosure" to LTS (#21027)

Backports #15841 to the LTS branch.

PR submitted by the release tooling.
[skip ci]

Author: WojciechMazur

Diff for: compiler/src/dotty/tools/dotc/ast/Desugar.scala

@@ -1437,7 +1437,7 @@ object desugar {
       DefDef(nme.ANON_FUN, params :: Nil, if (tpt == null) TypeTree() else tpt, body)
         .withSpan(span)
         .withMods(synthetic | Artifact),
-      Closure(Nil, Ident(nme.ANON_FUN), if (isContextual) ContextualEmptyTree else EmptyTree))
+      Closure(Nil, Ident(nme.ANON_FUN), if (isContextual) ContextualEmptyTree else EmptyTree).withSpan(span))
 
   /** If `nparams` == 1, expand partial function
    *

Diff for: compiler/src/dotty/tools/dotc/ast/NavigateAST.scala

@@ -4,7 +4,7 @@ package ast
 import core.Contexts.*
 import core.Decorators.*
 import util.Spans.*
-import Trees.{MemberDef, DefTree, WithLazyFields}
+import Trees.{Closure, MemberDef, DefTree, WithLazyFields}
 import dotty.tools.dotc.core.Types.AnnotatedType
 import dotty.tools.dotc.core.Types.ImportType
 import dotty.tools.dotc.core.Types.Type
@@ -76,7 +76,7 @@ object NavigateAST {
       var bestFit: List[Positioned] = path
       while (it.hasNext) {
         val path1 = it.next() match {
-          case p: Positioned => singlePath(p, path)
+          case p: Positioned if !p.isInstanceOf[Closure[?]] => singlePath(p, path)
           case m: untpd.Modifiers => childPath(m.productIterator, path)
           case xs: List[?] => childPath(xs.iterator, path)
           case _ => path

Diff for: compiler/test/dotty/tools/backend/jvm/DottyBytecodeTests.scala

@@ -1785,6 +1785,64 @@ class DottyBytecodeTests extends DottyBytecodeTest {
     }
   }
 
+
+  @Test def i15098 = {
+    val source =
+      """object Main {
+        |  def main(args: Array[String]): Unit = {
+        |    Array(1).foreach { n =>
+        |      val x = 123
+        |      println(n)
+        |    }
+        |  }
+        |}
+        """.stripMargin
+
+    checkBCode(source) { dir =>
+      val clsIn   = dir.lookupName("Main$.class", directory = false).input
+      val clsNode = loadClassNode(clsIn, skipDebugInfo = false)
+      val method  = getMethod(clsNode, "main")
+      val instructions = instructionsFromMethod(method).filter(_.isInstanceOf[LineNumber])
+
+      val expected = List(
+        LineNumber(3, Label(0)),
+      )
+
+      assertSameCode(instructions, expected)
+    }
+  }
+
+  @Test def i15098_2 = {
+    val source =
+      """object Main {
+        |  def main(args: Array[String]): Unit = {
+        |    Array(1).map { n =>
+        |      val x = 123
+        |      x + n
+        |    }.foreach { n =>
+        |      println(n)
+        |      println(n)
+        |    }
+        |  }
+        |}
+        """.stripMargin
+
+    checkBCode(source) { dir =>
+      val clsIn   = dir.lookupName("Main$.class", directory = false).input
+      val clsNode = loadClassNode(clsIn, skipDebugInfo = false)
+      val method  = getMethod(clsNode, "main")
+      val instructions = instructionsFromMethod(method).filter(_.isInstanceOf[LineNumber])
+
+      val expected = List(
+        LineNumber(3, Label(0)),
+        LineNumber(6, Label(15)),
+        LineNumber(3, Label(24)),
+        LineNumber(6, Label(27)),
+      )
+
+      assertSameCode(instructions, expected)
+    }
+  }
 }
 
 object invocationReceiversTestCode {

Diff for: tests/neg/i15741.scala

@@ -1,15 +1,15 @@
   def get(using Int): String = summon[Int].toString
 
-  def pf2: PartialFunction[String, Int ?=> String] = {
+  def pf2: PartialFunction[String, Int ?=> String] = { // error
     case "hoge" => get
     case "huga" => get
-  } // error
+  }
 
   type IS = Int ?=> String
 
-  def pf3: PartialFunction[String, IS] = {
+  def pf3: PartialFunction[String, IS] = { // error
     case "hoge" => get
     case "huga" => get
-  } // error
+  }
 
 

Diff for: tests/neg/i19351a.check

@@ -1,12 +1,4 @@
 -- Error: tests/neg/i19351a/Test.scala:8:34 ----------------------------------------------------------------------------
-8 |inline def not(b: Bool): Bool = ${notMacro('b)} // error // error
+8 |inline def not(b: Bool): Bool = ${notMacro('b)} // error
   |                                  ^
   |Cyclic macro dependency; macro refers to a toplevel symbol in tests/neg/i19351a/Test.scala from which the macro is called
--- [E046] Cyclic Error: tests/neg/i19351a/Test.scala:8:46 --------------------------------------------------------------
-8 |inline def not(b: Bool): Bool = ${notMacro('b)} // error // error
-  |                                              ^
-  |                                              Cyclic reference involving method $anonfun
-  |
-  |                                               Run with -explain-cyclic for more details.
-  |
-  | longer explanation available when compiling with `-explain`

Diff for: tests/neg/i19351a/Test.scala

@@ -5,7 +5,7 @@ type Bool = [R] => (R, R) => R
 val True: Bool = [R] => (t: R, _: R) => t
 val False: Bool = [R] => (_: R, f: R) => f
 
-inline def not(b: Bool): Bool = ${notMacro('b)} // error // error
+inline def not(b: Bool): Bool = ${notMacro('b)} // error
 inline def show(b: Bool): String = ${showMacro('b)}
 //inline def not(b: Bool): Bool = ${foldMacro('b, 'False, 'True)}
 //inline def show(b: Bool): String = ${foldMacro('b, '{"TRUE"}, '{"FALSE"})}

Diff for: tests/neg/i9299.scala

@@ -1,4 +1,4 @@
 type F <: F = 1 match { // error
-  case _ => foo.foo // error // error
+  case _ => foo.foo // error
 }
 def foo(a: Int): Unit = ???