From b49f016a416c0997de7ed6282a548dfe3f30cb70 Mon Sep 17 00:00:00 2001
From: i10416 <ito.yo16uh90616@gmail.com>
Date: Fri, 9 Feb 2024 17:13:47 +0900
Subject: [PATCH] fix(#i18645): overload ext method body in braces didn't
 compile

`tryWithImplicitOnQualifier` returned without attempting `tryInsertImplicitOnQualifier`,
which prevented the compiler from finding overloaded method, because `hasInnerErrors`
in `ProtoTypes` picked up the inner error propagated back from outer error.

When compiling `x.pprint(()=> { 123 })` before this commit, in `hasInnerErrors`,
`t` contains two sub trees; `Block(stmt, expr)` and `stmt`. The span of the former matches
the span of `t`, but that of the latter does not, which caused `hasInnerErrors` to return `true`,
but the error from the latter is duplicated with the error of parent tree `t`.

[Cherry-picked 5cf670741afaa6eb9bc670f6693fbb82fc5b4c01]
---
 .../src/dotty/tools/dotc/typer/ProtoTypes.scala  |  4 +++-
 tests/pos/i18645.scala                           | 16 ++++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)
 create mode 100644 tests/pos/i18645.scala

diff --git a/compiler/src/dotty/tools/dotc/typer/ProtoTypes.scala b/compiler/src/dotty/tools/dotc/typer/ProtoTypes.scala
index 6a75b8f6ee4f..9a99e44d8de3 100644
--- a/compiler/src/dotty/tools/dotc/typer/ProtoTypes.scala
+++ b/compiler/src/dotty/tools/dotc/typer/ProtoTypes.scala
@@ -394,7 +394,9 @@ object ProtoTypes {
       case closureDef(mdef) => hasInnerErrors(mdef.rhs)
       case _ =>
         t.existsSubTree { t1 =>
-          if t1.typeOpt.isError && t1.span.toSynthetic != t.span.toSynthetic then
+          if t1.typeOpt.isError
+            && t.span.toSynthetic != t1.span.toSynthetic
+            && t.typeOpt != t1.typeOpt then
             typr.println(i"error subtree $t1 of $t with ${t1.typeOpt}, spans = ${t1.span}, ${t.span}")
             true
           else
diff --git a/tests/pos/i18645.scala b/tests/pos/i18645.scala
new file mode 100644
index 000000000000..599396b678af
--- /dev/null
+++ b/tests/pos/i18645.scala
@@ -0,0 +1,16 @@
+trait Printable {
+  def pprint(v: () => String): Unit = {
+    println(v())
+  }
+}
+
+extension (ctx: Printable)
+  def pprint(f: () => Int): Unit = {
+    ctx.pprint(() => f().toString)
+  }
+
+val x = new Printable {}
+
+def test =
+  x.pprint(() => ( 234 ))
+  x.pprint(() => { 123 }) 
\ No newline at end of file