From e8c8038548d90a54eb2d2a3bfe4a13700d70dcce Mon Sep 17 00:00:00 2001
From: Dale Wijnand <dale.wijnand@gmail.com>
Date: Thu, 17 Aug 2023 23:56:57 +0100
Subject: [PATCH] Fix failing bounds check on default getter

The type arguments on the default argument had the wrong span, which
means that they were getting bounds checked.  This is in contrast the
other other type arguments (the ones on check itself), which aren't
bounds checked  - by not passing the isZeroExtent guard in
checkInferredWellFormed.
---
 .../src/dotty/tools/dotc/typer/Applications.scala |  2 +-
 tests/pos/i18253.orig.scala                       | 15 +++++++++++++++
 tests/pos/i18253.scala                            | 14 ++++++++++++++
 3 files changed, 30 insertions(+), 1 deletion(-)
 create mode 100644 tests/pos/i18253.orig.scala
 create mode 100644 tests/pos/i18253.scala

diff --git a/compiler/src/dotty/tools/dotc/typer/Applications.scala b/compiler/src/dotty/tools/dotc/typer/Applications.scala
index d1dffdbc9f9c..5acb067939cc 100644
--- a/compiler/src/dotty/tools/dotc/typer/Applications.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Applications.scala
@@ -333,7 +333,7 @@ object Applications {
       // it's crucial that the type tree is not copied directly as argument to
       // `cpy$default$1`. If it was, the variable `X'` would already be interpolated
       // when typing the default argument, which is too early.
-      spliceMeth(meth, fn).appliedToTypes(targs.tpes)
+      spliceMeth(meth, fn).appliedToTypeTrees(targs.map(targ => TypeTree(targ.tpe).withSpan(targ.span)))
     case _ => meth
   }
 
diff --git a/tests/pos/i18253.orig.scala b/tests/pos/i18253.orig.scala
new file mode 100644
index 000000000000..9efe1224ebfd
--- /dev/null
+++ b/tests/pos/i18253.orig.scala
@@ -0,0 +1,15 @@
+import compiletime.ops.int.Max
+
+trait DFSInt[W <: Int]
+trait Candidate[R]:
+  type OutW <: Int
+object Candidate:
+  given [W <: Int, R <: DFSInt[W]]: Candidate[R] with
+    type OutW = W
+
+def foo[R](rhs: R)(using icR: Candidate[R]): DFSInt[Max[8, icR.OutW]] = ???
+
+object Test:
+  def check[A](a: A, clue: Int = 1): Unit = ???
+  val x: DFSInt[8] = ???
+  check(foo(x))
diff --git a/tests/pos/i18253.scala b/tests/pos/i18253.scala
new file mode 100644
index 000000000000..8f395ee8e943
--- /dev/null
+++ b/tests/pos/i18253.scala
@@ -0,0 +1,14 @@
+import scala.compiletime.ops.int.Max
+
+trait Foo[A]
+trait Bar[B]:
+  type Out <: Int
+object Bar:
+  given inst[C <: Int]: Bar[C] with
+    type Out = C
+
+class Test:
+  def mkFoo(using bx: Bar[2]): Foo[Max[1, bx.Out]] = ???
+  def check[Y](yy: Y, clue: Int = 1): Unit = ()
+
+  def test: Unit = check(mkFoo)