Allow non-hot values in SeqLiterals

Closes #14460, #14751

Do not ensure that elements in a SeqLiteral are Hot.

Review by @liufengyun

Author: Xavientois

compiler/src/dotty/tools/dotc/transform/init/Semantic.scala

@@ -1234,9 +1234,9 @@ object Semantic {
 
       case SeqLiteral(elems, elemtpt) =>
         val ress = elems.map { elem =>
-          eval(elem, thisV, klass).ensureHot("May only use initialized value as method arguments", elem)
+          eval(elem, thisV, klass)
         }
-        Result(Hot, ress.flatMap(_.errors))
+        Result(ress.map(_.value).join, ress.flatMap(_.errors))
 
       case Inlined(call, bindings, expansion) =>
         val trace1 = trace.add(expr)

tests/init/neg/enum-desugared.check

@@ -1,8 +1,4 @@
 -- Error: tests/init/neg/leak-warm.scala:18:26 -------------------------------------------------------------------------
-18 |    val l: List[A] = List(c, d) // error // error
-   |                          ^
-   |           Cannot prove that the value is fully initialized. May only use initialized value as method arguments.
--- Error: tests/init/neg/leak-warm.scala:18:29 -------------------------------------------------------------------------
-18 |    val l: List[A] = List(c, d) // error // error
-   |                             ^
-   |           Cannot prove that the value is fully initialized. May only use initialized value as method arguments.
+18 |    val l: List[A] = List(c, d) // error
+   |                          ^^^^
+   |             Cannot prove that the value is fully initialized. Only initialized values may be used as arguments.

tests/init/neg/enum.check

@@ -15,6 +15,6 @@ object leakWarm {
     }
     val c = new C(1, 2)
     val d = new D(3, 4)
-    val l: List[A] = List(c, d) // error // error
+    val l: List[A] = List(c, d) // error
     val l2 = l.map(_.m())
 }

tests/init/neg/leak-warm.check

@@ -14,7 +14,7 @@ object ErrorMessageID {
   final val NoExplanationID = $new(1, "NoExplanationID")
 
   private[this] val $values: Array[ErrorMessageID] =
-    Array(this.LazyErrorId, this.NoExplanationID) // error // error
+    Array(this.LazyErrorId, this.NoExplanationID)
 
   def values: Array[ErrorMessageID] = $values.clone()
 

tests/init/neg/leak-warm.scala

@@ -1,6 +1,6 @@
 enum ErrorMessageID extends java.lang.Enum[ErrorMessageID] {
     case
         LazyErrorId,
-        NoExplanationID // error
+        NoExplanationID
     def errorNumber = ordinal - 2
 }