From 0e949172f8d2c295563c0a48fece9d3532c9db37 Mon Sep 17 00:00:00 2001
From: Martin Odersky <odersky@gmail.com>
Date: Sat, 12 Jun 2021 17:18:05 +0200
Subject: [PATCH] Don't insert semicolons in conditions unless indented

In a statement like this
```scala
if foo
    (bar)
then
```
we would never expect a semicolon to be inserted between `foo` and `bar`. The `foo`
would need to be indented itself for this to happen.

So, the following is OK
```scala
if
  val x = ...
  x > 0
then
```
But the following is not:
```scala
if val x = ...
  x > 0
```

Fixes #12757
---
 compiler/src/dotty/tools/dotc/parsing/Parsers.scala | 9 +++++----
 tests/pos/i12757.scala                              | 8 ++++++++
 2 files changed, 13 insertions(+), 4 deletions(-)
 create mode 100644 tests/pos/i12757.scala

diff --git a/compiler/src/dotty/tools/dotc/parsing/Parsers.scala b/compiler/src/dotty/tools/dotc/parsing/Parsers.scala
index 0f3ae09d1879..8f0a57dc2fc8 100644
--- a/compiler/src/dotty/tools/dotc/parsing/Parsers.scala
+++ b/compiler/src/dotty/tools/dotc/parsing/Parsers.scala
@@ -72,8 +72,9 @@ object Parsers {
     if source.isSelfContained then new ScriptParser(source)
     else new Parser(source)
 
-  private val InCase: Region => Region = Scanners.InCase.apply
-  private val InCond: Region => Region = Scanners.InBraces.apply
+  private val InCase: Region => Region = Scanners.InCase(_)
+  private val InCond: Region => Region = Scanners.InParens(LPAREN, _)
+  private val InFor : Region => Region = Scanners.InBraces(_)
 
   abstract class ParserCommon(val source: SourceFile)(using Context) {
 
@@ -167,7 +168,7 @@ object Parsers {
   class Parser(source: SourceFile)(using Context) extends ParserCommon(source) {
 
     val in: Scanner = new Scanner(source)
-    // in.debugTokenStream = true    // uncomment to see the token stream of the standard scanner, but not syntax highlighting
+    //in.debugTokenStream = true    // uncomment to see the token stream of the standard scanner, but not syntax highlighting
 
     /** This is the general parse entry point.
      *  Overridden by ScriptParser
@@ -2553,7 +2554,7 @@ object Parsers {
             if (in.token == INDENT)
               inBracesOrIndented(enumerators())
             else {
-              val ts = inSepRegion(InCond)(enumerators())
+              val ts = inSepRegion(InFor)(enumerators())
               if (rewriteToOldSyntax(Span(start)) && ts.nonEmpty)
                 if (ts.head.sourcePos.startLine != ts.last.sourcePos.startLine) {
                   patch(source, Span(forEnd), " {")
diff --git a/tests/pos/i12757.scala b/tests/pos/i12757.scala
new file mode 100644
index 000000000000..906458f58e63
--- /dev/null
+++ b/tests/pos/i12757.scala
@@ -0,0 +1,8 @@
+val x = Some(10)
+
+def f =
+   if x.exists
+         (x => x == 10) then
+      println("Yes")
+   else
+      println("No")
\ No newline at end of file