Allow document to be httpPayload target

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Smithy Changelog
 
+## 1.0.1 (TBD)
+
+### Features
+
+* `httpPayload` can now target document shapes.
+
 ## 1.0.0 (2020-05-04)
 
 ***Note***: Changes marked with "[BC]" are breaking changes more accurately described in the

docs/source/1.0/spec/core/http-traits.rst

@@ -641,9 +641,9 @@ Summary
 Trait selector
     .. code-block:: none
 
-        structure > :test(member > :test(string, blob, structure, union))
+        structure > :test(member > :test(string, blob, structure, union, document))
 
-    *Structure members that target a string, blob, structure, or union*
+    *Structure members that target a string, blob, structure, union, or document*
 Value type
     Annotation trait.
 Conflicts with
@@ -671,8 +671,8 @@ Serialization rules:
 
 #. When a string or blob member is referenced, the raw value is serialized
    as the body of the message.
-#. When a :ref:`structure` or :ref:`union` is targeted, the shape value
-   is serialized as a :ref:`protocol-specific <protocolDefinition-trait>`
+#. When a :ref:`structure`, :ref:`union`, or document is targeted, the shape
+   value is serialized as a :ref:`protocol-specific <protocolDefinition-trait>`
    document that is sent as the body of the message.
 
 

smithy-model/src/main/resources/software/amazon/smithy/model/loader/prelude-traits.smithy

@@ -501,7 +501,7 @@ string httpHeader
 string httpPrefixHeaders
 
 /// Binds a single structure member to the body of an HTTP request.
-@trait(selector: "structure > :test(member > :test(string, blob, structure, union))",
+@trait(selector: "structure > :test(member > :test(string, blob, structure, union, document))",
         conflicts: [httpLabel, httpQuery, httpHeader, httpPrefixHeaders],
         structurallyExclusive: "member")
 @tags(["diff.error.const"])