From 7b48e9dffb06bf7eb577b6629131e8bbf24e7b3a Mon Sep 17 00:00:00 2001
From: i10416 <ito.yo16uh90616@gmail.com>
Date: Sun, 22 Oct 2023 15:15:43 +0900
Subject: [PATCH 1/2] fix(#18265): crash on extension method without body

This commit fixes a bug that causes Scala compiler to crash due to position error
when an extension method followed by a newline has neither type annotation nor `= <expr>`.

This commit is based on https://github.com/lampepfl/dotty/pull/18445.

Co-Authored-By: @hamzaremmal

[Cherry-picked caf30e3d1186ed306ba5c8ef93b148ad7db6dc54]
---
 compiler/src/dotty/tools/dotc/parsing/Parsers.scala | 2 ++
 tests/neg/i18265.check                              | 6 ++++++
 tests/neg/i18265.scala                              | 5 +++++
 3 files changed, 13 insertions(+)
 create mode 100644 tests/neg/i18265.check
 create mode 100644 tests/neg/i18265.scala

diff --git a/compiler/src/dotty/tools/dotc/parsing/Parsers.scala b/compiler/src/dotty/tools/dotc/parsing/Parsers.scala
index 66e001403d6a..6add504a98cb 100644
--- a/compiler/src/dotty/tools/dotc/parsing/Parsers.scala
+++ b/compiler/src/dotty/tools/dotc/parsing/Parsers.scala
@@ -2607,6 +2607,8 @@ object Parsers {
       parents match {
         case parent :: Nil if !in.isNestedStart =>
           reposition(if (parent.isType) ensureApplied(wrapNew(parent)) else parent)
+        case tkn if in.token == INDENT =>
+          New(templateBodyOpt(emptyConstructor, parents, Nil))
         case _ =>
           New(reposition(templateBodyOpt(emptyConstructor, parents, Nil)))
       }
diff --git a/tests/neg/i18265.check b/tests/neg/i18265.check
new file mode 100644
index 000000000000..fc9f044f4e83
--- /dev/null
+++ b/tests/neg/i18265.check
@@ -0,0 +1,6 @@
+-- [E019] Syntax Error: tests/neg/i18265.scala:5:13 --------------------------------------------------------------------
+5 |    def twice // error
+  |             ^
+  |             Missing return type
+  |
+  | longer explanation available when compiling with `-explain`
diff --git a/tests/neg/i18265.scala b/tests/neg/i18265.scala
new file mode 100644
index 000000000000..5cc67b7bd182
--- /dev/null
+++ b/tests/neg/i18265.scala
@@ -0,0 +1,5 @@
+trait Foo
+
+val foo = new Foo:
+  extension (s: String)
+    def twice // error

From 45faafb1051da700e8cf4746a6567e6b1f8afdec Mon Sep 17 00:00:00 2001
From: i10416 <ito.yo16uh90616@gmail.com>
Date: Sun, 22 Oct 2023 17:03:07 +0900
Subject: [PATCH 2/2] maybefix: update semanticdb expected output

[Cherry-picked 07761aec094af62c4ed7621a0362167cbe66eb1b]
---
 tests/semanticdb/expect/StructuralTypes.expect.scala | 4 ++--
 tests/semanticdb/metac.expect                        | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/tests/semanticdb/expect/StructuralTypes.expect.scala b/tests/semanticdb/expect/StructuralTypes.expect.scala
index 96c7181d6f10..98aaca95f880 100644
--- a/tests/semanticdb/expect/StructuralTypes.expect.scala
+++ b/tests/semanticdb/expect/StructuralTypes.expect.scala
@@ -16,7 +16,7 @@ object StructuralTypes/*<-example::StructuralTypes.*/:
 
   val V/*<-example::StructuralTypes.V.*/: Object/*->java::lang::Object#*/ {
     def scalameta/*<-local4*/: String/*->scala::Predef.String#*/
-  } = /*<-local6*/new:
-    def scalameta/*<-local5*/ = "4.0"
+  } = new:
+    /*<-local6*/def scalameta/*<-local5*/ = "4.0"
   V/*->example::StructuralTypes.V.*/.scalameta/*->scala::reflect::Selectable#selectDynamic().*/
 end StructuralTypes/*->example::StructuralTypes.*/
\ No newline at end of file
diff --git a/tests/semanticdb/metac.expect b/tests/semanticdb/metac.expect
index e05a645c0141..00aa8673f015 100644
--- a/tests/semanticdb/metac.expect
+++ b/tests/semanticdb/metac.expect
@@ -3472,7 +3472,7 @@ Occurrences:
 [16:9..16:15): Object -> java/lang/Object#
 [17:8..17:17): scalameta <- local4
 [17:19..17:25): String -> scala/Predef.String#
-[18:6..18:6): <- local6
+[19:4..19:4): <- local6
 [19:8..19:17): scalameta <- local5
 [20:2..20:3): V -> example/StructuralTypes.V.
 [20:4..20:13): scalameta -> scala/reflect/Selectable#selectDynamic().