Add documentation and missing optional seal

Author: nicolasstucki

compiler/src/dotty/tools/dotc/tastyreflect/ReflectionCompilerInterface.scala

@@ -1883,10 +1883,9 @@ class ReflectionCompilerInterface(val rootContext: core.Contexts.Context) extend
   def QuotedType_unseal(self: scala.quoted.Type[?])(using ctx: Context): TypeTree =
     PickledQuotes.quotedTypeToTree(self)
 
-  /** Convert `Term` to an `quoted.Expr[Any]`  */
-  def QuotedExpr_seal(self: Term)(using ctx: Context): scala.quoted.Expr[Any] = self.tpe.widen match {
-    case _: Types.MethodType | _: Types.PolyType => throw new Exception("Cannot seal a partially applied Term. Try eta-expanding the term first.")
-    case _ => new TastyTreeExpr(self, compilerId)
+  def QuotedExpr_seal(self: Term)(using ctx: Context): Option[scala.quoted.Expr[Any]] = self.tpe.widen match {
+    case _: Types.MethodType | _: Types.PolyType => None
+    case _ => Some(new TastyTreeExpr(self, compilerId))
   }
 
   /** Checked cast to a `quoted.Expr[U]` */

library/src/scala/tasty/Reflection.scala

@@ -619,13 +619,26 @@ class Reflection(private[scala] val internal: CompilerInterface) { self =>
 
   extension TermOps on (self: Term) {
 
-    /** Convert `Term` to an `quoted.Expr[Any]` */
+    /** Convert `Term` to an `quoted.Expr[Any]` if the term is a valid expression or throws */
     def seal(using ctx: Context): scala.quoted.Expr[Any] =
+      internal.QuotedExpr_seal(self).getOrElse {
+        throw new Exception("Cannot seal a partially applied Term. Try eta-expanding the term first.")
+      }
+
+    /** Convert `Term` to an `quoted.Expr[Any]` if the term is a valid expression */
+    def sealOpt(using ctx: Context): Option[scala.quoted.Expr[Any]] =
       internal.QuotedExpr_seal(self)
 
+    /** Type of this term */
     def tpe(using ctx: Context): Type = internal.Term_tpe(self)
+
+    /** Replace Inlined nodes and InlineProxy references to underlying arguments */
     def underlyingArgument(using ctx: Context): Term = internal.Term_underlyingArgument(self)
+
+    /** Replace Ident nodes references to the underlying tree that defined them */
     def underlying(using ctx: Context): Term = internal.Term_underlying(self)
+
+    /** Converts a partally applied term into a lambda expression */
     def etaExpand(using ctx: Context): Term = internal.Term_etaExpand(self)
 
     /** A unary apply node with given argument: `tree(arg)` */

library/src/scala/tasty/reflect/CompilerInterface.scala

@@ -1434,9 +1434,8 @@ trait CompilerInterface {
   /** View this expression `quoted.Type[T]` as a `TypeTree` */
   def QuotedType_unseal(self: scala.quoted.Type[_])(using ctx: Context): TypeTree
 
-  /** Convert `Term` to an `quoted.Expr[Any]` */
-  def QuotedExpr_seal(self: Term)(using ctx: Context): scala.quoted.Expr[Any]
-
+  /** Convert `Term` to an `quoted.Expr[Any]` if the term is a valid expression */
+  def QuotedExpr_seal(self: Term)(using ctx: Context): Option[scala.quoted.Expr[Any]]
 
   /** Convert `Type` to an `quoted.Type[_]` */
   def QuotedType_seal(self: Type)(using ctx: Context): scala.quoted.Type[_]