Fix unchecked PatDef in compiler

Author: liufengyun

compiler/src/dotty/tools/dotc/transform/ContextFunctionResults.scala

@@ -46,7 +46,7 @@ object ContextFunctionResults:
   def contextResultCount(sym: Symbol)(using Context): Int =
     sym.getAnnotation(defn.ContextResultCountAnnot) match
       case Some(annot) =>
-        val ast.Trees.Literal(Constant(crCount: Int)) :: Nil: @unchecked = annot.arguments
+        val ast.Trees.Literal(Constant(crCount: Int)) :: Nil = annot.arguments: @unchecked
         crCount
       case none => 0
 
@@ -73,7 +73,7 @@ object ContextFunctionResults:
     def contextParamCount(tp: Type, crCount: Int): Int =
       if crCount == 0 then 0
       else
-        val defn.ContextFunctionType(params, resTpe, isErased): @unchecked = tp
+        val defn.ContextFunctionType(params, resTpe, isErased) = tp: @unchecked
         val rest = contextParamCount(resTpe, crCount - 1)
         if isErased then rest else params.length + rest
 
@@ -106,7 +106,7 @@ object ContextFunctionResults:
       def missingCR(tp: Type, crCount: Int): (Type, Int) =
         if crCount == 0 then (tp, 0)
         else
-          val defn.ContextFunctionType(formals, resTpe, isErased): @unchecked = tp
+          val defn.ContextFunctionType(formals, resTpe, isErased) = tp: @unchecked
           val result @ (rt, nparams) = missingCR(resTpe, crCount - 1)
           assert(nparams <= paramCount)
           if nparams == paramCount || isErased then result

compiler/src/dotty/tools/dotc/transform/Erasure.scala

@@ -490,15 +490,15 @@ object Erasure {
       def abstracted(args: List[Tree], tp: Type, pt: Type)(using Context): Tree =
         if args.length < targetLength then
           try
-            val defn.ContextFunctionType(argTpes, resTpe, isErased): @unchecked = tp
+            val defn.ContextFunctionType(argTpes, resTpe, isErased) = tp: @unchecked
             if isErased then abstracted(args, resTpe, pt)
             else
               val anonFun = newSymbol(
                 ctx.owner, nme.ANON_FUN, Flags.Synthetic | Flags.Method,
                 MethodType(argTpes, resTpe), coord = tree.span.endPos)
               anonFun.info = transformInfo(anonFun, anonFun.info)
               def lambdaBody(refss: List[List[Tree]]) =
-                val refs :: Nil : @unchecked = refss
+                val refs :: Nil = refss: @unchecked
                 val expandedRefs = refs.map(_.withSpan(tree.span.endPos)) match
                   case (bunchedParam @ Ident(nme.ALLARGS)) :: Nil =>
                     argTpes.indices.toList.map(n =>

compiler/src/dotty/tools/dotc/typer/Typer.scala

@@ -1877,7 +1877,7 @@ class Typer extends Namer
       case _ =>
         var name = tree.name
         if (name == nme.WILDCARD && tree.mods.is(Given)) {
-          val Typed(_, tpt): @unchecked = tree.body
+          val Typed(_, tpt) = tree.body: @unchecked
           name = desugar.inventGivenOrExtensionName(tpt)
         }
         if (name == nme.WILDCARD) body1