chore: Fix nightlies after recent changes (#4312)

The issues caused by scala/scala3#15877

Author: tgodzik

mtags/src/main/scala-3/scala/meta/internal/pc/MetalsInteractive.scala

@@ -248,9 +248,14 @@ object MetalsInteractive:
             target.sourcePos.contains(pos) =>
         List((target.symbol, target.typeOpt))
 
-      case path @ head :: tl =>
+      case path @ head :: tail =>
         if head.symbol.is(Synthetic) then
-          enclosingSymbolsWithExpressionType(tl, pos, indexed, skipCheckOnName)
+          enclosingSymbolsWithExpressionType(
+            tail,
+            pos,
+            indexed,
+            skipCheckOnName,
+          )
         else if head.symbol != NoSymbol then
           if skipCheckOnName ||
             MetalsInteractive.isOnName(
@@ -259,12 +264,18 @@ object MetalsInteractive:
               indexed.ctx.source,
             )
           then List((head.symbol, head.typeOpt))
+          /* Type tree for List(1) has an Int type variable, which has span
+           * but doesn't exist in code.
+           * https://github.com/lampepfl/dotty/issues/15937
+           */
+          else if head.isInstanceOf[TypeTree] then
+            enclosingSymbolsWithExpressionType(tail, pos, indexed)
           else Nil
         else
           val recovered = recoverError(head, indexed)
           if recovered.isEmpty then
             enclosingSymbolsWithExpressionType(
-              tl,
+              tail,
               pos,
               indexed,
               skipCheckOnName,

tests/cross/src/test/scala/tests/pc/CompletionKeywordSuite.scala

@@ -290,6 +290,8 @@ class CompletionKeywordSuite extends BaseCompletionSuite {
       |""".stripMargin,
     """|return
        |""".stripMargin,
+    // methods add in 3.2.1
+    filter = item => !item.contains("retains"),
   )
 
   check(
@@ -302,6 +304,8 @@ class CompletionKeywordSuite extends BaseCompletionSuite {
       |}
       |""".stripMargin,
     "",
+    // methods add in 3.2.1
+    filter = item => !item.contains("retains"),
   )
 
   check(
@@ -319,6 +323,8 @@ class CompletionKeywordSuite extends BaseCompletionSuite {
     compat = Map(
       "3" -> ""
     ),
+    // methods add in 3.2.1
+    filter = item => !item.contains("retains"),
   )
 
   check(
@@ -329,6 +335,8 @@ class CompletionKeywordSuite extends BaseCompletionSuite {
       |ret@@
       |""".stripMargin,
     "",
+    // methods add in 3.2.1
+    filter = item => !item.contains("retains"),
   )
 
   check(