Fix #12351: add test

Fix renaming as well

Author: liufengyun

compiler/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala

@@ -885,7 +885,7 @@ class TreeUnpickler(reader: TastyReader,
         sym.info = ta.avoidPrivateLeaks(sym)
 
       if (ctx.settings.YreadComments.value) {
-        assert(ctx.docCtx.isDefined, "`-Yread-comments` enabled, but no `docCtx` is set.")
+        assert(ctx.docCtx.isDefined, "`-Yread-docs` enabled, but no `docCtx` is set.")
         commentUnpicklerOpt.foreach { commentUnpickler =>
           val comment = commentUnpickler.commentAt(start)
           ctx.docCtx.get.addDocstring(tree.symbol, comment)

compiler/test/dotty/tools/dotc/BootstrappedOnlyCompilationTests.scala

@@ -118,6 +118,7 @@ class BootstrappedOnlyCompilationTests {
     aggregateTests(
       compileFilesInDir("tests/run-macros", defaultOptions.and("-Xcheck-macros")),
       compileFilesInDir("tests/run-custom-args/Yretain-trees", defaultOptions and "-Yretain-trees"),
+      compileFilesInDir("tests/run-custom-args/Yread-comments", defaultOptions and "-Yread-docs"),
       compileFilesInDir("tests/run-custom-args/run-macros-erased", defaultOptions.and("-language:experimental.erasedDefinitions").and("-Xcheck-macros")),
     )
   }.checkRuns()

tests/run-custom-args/Yread-comments/i12351/GetDocString_1.scala

@@ -0,0 +1,11 @@
+import scala.quoted.*
+
+/** HELLO */
+case class Data(test: Boolean)
+
+inline def getDocString[T]: Option[String] = ${ getDocStringImpl[T] }
+
+private def getDocStringImpl[T : Type](using Quotes): Expr[Option[String]] = {
+    import quotes.reflect.*
+    Expr(TypeRepr.of[T].typeSymbol.docstring)
+}

tests/run-custom-args/Yread-comments/i12351/Test_2.scala

@@ -0,0 +1,4 @@
+@main def Test(): Unit = {
+    println(getDocString[Data])
+    assert(getDocString[Data].nonEmpty)
+}