remove unneeded case

If the union only has ref values,
then we don’t need an extra case.

Also, some linear format

codegen/smithy-dafny-codegen/src/main/java/software/amazon/polymorph/smithydafny/DafnyApiCodegen.java

@@ -1229,7 +1229,7 @@ private TokenTree OperationMemberValidState(
  // then we can not prove freshness of these items
  final TokenTree removeInputs = direction == InputOutput.OUTPUT
  ? OperationModifiesInputs(operationShape.getId(), implementationType)
- .prependSeperated(Token.of("-"))
+ .prependSeperated(Token.of("\n -"))
  : TokenTree.empty();
 
  // We need to do 3 things here
@@ -1327,12 +1327,15 @@ private TokenTree OperationMemberValidState(
  .lineSeparated();
  } else if (isUnion && member.isRequired()) {
  // Required Union
+
+ final UnionShape union = memberShape
+ .asUnionShape()
+ .get();
+
  return TokenTree
  .of(
  TokenTree.of("\n && (match %s ".formatted(varName)),
- TokenTree.of(memberShape
- .asUnionShape()
- .get()
+ TokenTree.of(union
  .members()
  .stream()
  .filter(this::OnlyReferenceStructures)
@@ -1358,19 +1361,30 @@ private TokenTree OperationMemberValidState(
  )
  : TokenTree.empty()
  )
+ .flatten()
+ .dropEmpty()
  .lineSeparated()))
  .lineSeparated(),
- TokenTree.of("case _ => true)")
+ TokenTree.of(
+ union
+ .members()
+ .stream()
+ .allMatch(this::OnlyReferenceStructures)
+ ? ")"
+ : "case _ => true)")
  )
  .lineSeparated();
  } else if (isUnion && !member.isRequired()) {
  // Optional Union
+
+ final UnionShape union = memberShape
+ .asUnionShape()
+ .get();
+
  return TokenTree
  .of(
  TokenTree.of("\n && ( %1$s.Some? \n ==> match %1$s.value ".formatted(varName)),
- TokenTree.of(memberShape
- .asUnionShape()
- .get()
+ TokenTree.of(union
  .members()
  .stream()
  .filter(this::OnlyReferenceStructures)
@@ -1396,9 +1410,17 @@ private TokenTree OperationMemberValidState(
  )
  : TokenTree.empty()
  )
+ .flatten()
+ .dropEmpty()
  .lineSeparated()))
  .lineSeparated(),
- TokenTree.of("case _ => true)")
+ TokenTree.of(
+ union
+ .members()
+ .stream()
+ .allMatch(this::OnlyReferenceStructures)
+ ? ")"
+ : "case _ => true)")
  )
  .lineSeparated();
  } else {
@@ -1537,7 +1559,15 @@ private TokenTree OperationMemberModifies(
  "case %s(o) => o.Modifies"
  .formatted(s.getMemberName())
  ))),
- Token.of("case _ => {})")
+ TokenTree.of(
+ memberShape
+ .asUnionShape()
+ .get()
+ .members()
+ .stream()
+ .allMatch(this::OnlyReferenceStructures)
+ ? ")"
+ : "case _ => {})")
  )
  .flatten()
  .dropEmpty()
@@ -1555,7 +1585,7 @@ private TokenTree OperationMemberModifies(
  return TokenTree.of(
  TokenTree
  .of(
- Token.of("(if %1$s.Some? then match %1$s.value ".formatted(varName)),
+ Token.of("(if %1$s.Some? then \n match %1$s.value ".formatted(varName)),
  Token.of(memberShape
  .asUnionShape()
  .get()
@@ -1567,7 +1597,15 @@ private TokenTree OperationMemberModifies(
  "case %s(o) => o.Modifies"
  .formatted(s.getMemberName())
  ))),
- Token.of("case _ => {}"),
+ TokenTree.of(
+ memberShape
+ .asUnionShape()
+ .get()
+ .members()
+ .stream()
+ .allMatch(this::OnlyReferenceStructures)
+ ? ""
+ : "case _ => {}"),
  Token.of("else {})")
  )
  .flatten()