From 24c3e7f601c6ba74c541f1603251253bfde45ab3 Mon Sep 17 00:00:00 2001
From: Wojciech Mazur <wmazur@virtuslab.com>
Date: Wed, 27 Nov 2024 23:54:11 +0100
Subject: [PATCH] Add migration rewrite deprecated assignment syntax

---
 .../dotty/tools/dotc/reporting/messages.scala |  1 +
 .../src/dotty/tools/dotc/typer/Typer.scala    |  3 +++
 .../dotty/tools/dotc/CompilationTests.scala   |  1 +
 .../ambigious-named-tuple-assignment.check    | 19 +++++++++++++++++++
 .../ambigious-named-tuple-assignment.scala    | 19 +++++++++++++++++++
 tests/warn/21681.check                        |  1 +
 tests/warn/21681b.check                       |  1 +
 tests/warn/21681c.check                       |  1 +
 tests/warn/21770.check                        |  1 +
 9 files changed, 47 insertions(+)
 create mode 100644 tests/rewrites/ambigious-named-tuple-assignment.check
 create mode 100644 tests/rewrites/ambigious-named-tuple-assignment.scala

diff --git a/compiler/src/dotty/tools/dotc/reporting/messages.scala b/compiler/src/dotty/tools/dotc/reporting/messages.scala
index 2e74c5816c5e..b396aa62f599 100644
--- a/compiler/src/dotty/tools/dotc/reporting/messages.scala
+++ b/compiler/src/dotty/tools/dotc/reporting/messages.scala
@@ -3350,6 +3350,7 @@ final class DeprecatedAssignmentSyntax(key: Name, value: untpd.Tree)(using Conte
       |not as an assignment.
       |
       |To assign a value, use curly braces: `{${key} = ${value}}`."""
+      + Message.rewriteNotice("This", version = SourceVersion.`3.6-migration`)
 
   override protected def explain(using Context): String = ""
 
diff --git a/compiler/src/dotty/tools/dotc/typer/Typer.scala b/compiler/src/dotty/tools/dotc/typer/Typer.scala
index d74a69f2a114..f5318759bac2 100644
--- a/compiler/src/dotty/tools/dotc/typer/Typer.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Typer.scala
@@ -3442,6 +3442,9 @@ class Typer(@constructorOnly nestingLevel: Int = 0) extends Namer
           // If there are no errors typing the above, then the named tuple is
           // ambiguous and we issue a warning.
           report.migrationWarning(DeprecatedAssignmentSyntax(name, value), tree.srcPos)
+          if MigrationVersion.AmbiguousNamedTupleSyntax.needsPatch then
+            patch(tree.source, Span(tree.span.start, tree.span.start + 1), "{")
+            patch(tree.source, Span(tree.span.end - 1, tree.span.end), "}")
       case _ => ()
 
   /** Retrieve symbol attached to given tree */
diff --git a/compiler/test/dotty/tools/dotc/CompilationTests.scala b/compiler/test/dotty/tools/dotc/CompilationTests.scala
index 3bd3b5138fad..9f72db6fc390 100644
--- a/compiler/test/dotty/tools/dotc/CompilationTests.scala
+++ b/compiler/test/dotty/tools/dotc/CompilationTests.scala
@@ -80,6 +80,7 @@ class CompilationTests {
       compileDir("tests/rewrites/annotation-named-pararamters", defaultOptions.and("-rewrite", "-source:3.6-migration")),
       compileFile("tests/rewrites/i21418.scala", unindentOptions.and("-rewrite", "-source:3.5-migration")),
       compileFile("tests/rewrites/infix-named-args.scala", defaultOptions.and("-rewrite", "-source:3.6-migration")),
+      compileFile("tests/rewrites/ambigious-named-tuple-assignment.scala", defaultOptions.and("-rewrite", "-source:3.6-migration")),
     ).checkRewrites()
   }
 
diff --git a/tests/rewrites/ambigious-named-tuple-assignment.check b/tests/rewrites/ambigious-named-tuple-assignment.check
new file mode 100644
index 000000000000..00e6cc4112f1
--- /dev/null
+++ b/tests/rewrites/ambigious-named-tuple-assignment.check
@@ -0,0 +1,19 @@
+import scala.language.experimental.namedTuples
+
+object i21770:
+  def f(g: Int  => Unit) = g(0)
+  var cache: Option[Int] = None
+  f(i => {cache = Some(i)})
+  
+object i21861:
+  var age: Int = 28
+  {
+    age = 29
+  }
+  
+  
+object i21861c:
+  def age: Int = ???
+  def age_=(x: Int): Unit = ()
+  age = 29
+  { age = 29 }
diff --git a/tests/rewrites/ambigious-named-tuple-assignment.scala b/tests/rewrites/ambigious-named-tuple-assignment.scala
new file mode 100644
index 000000000000..e9685b7b58cf
--- /dev/null
+++ b/tests/rewrites/ambigious-named-tuple-assignment.scala
@@ -0,0 +1,19 @@
+import scala.language.experimental.namedTuples
+
+object i21770:
+  def f(g: Int  => Unit) = g(0)
+  var cache: Option[Int] = None
+  f(i => (cache = Some(i)))
+  
+object i21861:
+  var age: Int = 28
+  (
+    age = 29
+  )
+  
+  
+object i21861c:
+  def age: Int = ???
+  def age_=(x: Int): Unit = ()
+  age = 29
+  ( age = 29 )
diff --git a/tests/warn/21681.check b/tests/warn/21681.check
index 5156a600d609..adf3586e6e0b 100644
--- a/tests/warn/21681.check
+++ b/tests/warn/21681.check
@@ -5,3 +5,4 @@
   |  not as an assignment.
   |
   |  To assign a value, use curly braces: `{age = 29}`.
+  |  This can be rewritten automatically under -rewrite -source 3.6-migration.
diff --git a/tests/warn/21681b.check b/tests/warn/21681b.check
index dd28df3168ed..09c007f351b4 100644
--- a/tests/warn/21681b.check
+++ b/tests/warn/21681b.check
@@ -5,3 +5,4 @@
   |  not as an assignment.
   |
   |  To assign a value, use curly braces: `{age = 29}`.
+  |  This can be rewritten automatically under -rewrite -source 3.6-migration.
diff --git a/tests/warn/21681c.check b/tests/warn/21681c.check
index bfb62618cbb9..20273f723384 100644
--- a/tests/warn/21681c.check
+++ b/tests/warn/21681c.check
@@ -5,3 +5,4 @@
   |  not as an assignment.
   |
   |  To assign a value, use curly braces: `{age = 29}`.
+  |  This can be rewritten automatically under -rewrite -source 3.6-migration.
diff --git a/tests/warn/21770.check b/tests/warn/21770.check
index 6c978a6078a2..7853d77a423c 100644
--- a/tests/warn/21770.check
+++ b/tests/warn/21770.check
@@ -5,3 +5,4 @@
   |         not as an assignment.
   |
   |         To assign a value, use curly braces: `{cache = Some(i)}`.
+  |         This can be rewritten automatically under -rewrite -source 3.6-migration.