* hcldec: Attribute evaluation (as part of `AttrSpec` or `BlockAttrsSpec`) now captures expression evaluation metadata in any errors it produces during type conversions, allowing for better feedback in calling applications that are able to make use of this metadata when printing diagnostic messages. ([#329](https://github.com/hashicorp/hcl/pull/329))
* hclsyntax: `IndexExpr`, `SplatExpr`, and `RelativeTraversalExpr` will now report a source range that covers all of their child expression nodes. Previously they would report only the operator part, such as `["foo"]`, `[*]`, or `.foo`, which was problematic for callers using source ranges for code analysis. ([#328](https://github.com/hashicorp/hcl/pull/328))
* hclwrite: Parser will no longer panic when the input includes index, splat, or relative traversal syntax. ([#328](https://github.com/hashicorp/hcl/pull/328))
* gohcl: When decoding into a struct value with some fields already populated, those values will be retained if not explicitly overwritten in the given HCL body, with similar overriding/merging behavior as `json.Unmarshal` in the Go standard library.
* hclwrite: New interface to set the expression for an attribute to be a raw token sequence, with no special processing. This has some caveats, so if you intend to use it please refer to the godoc comments. ([#320](https://github.com/hashicorp/hcl/pull/320))
* hclwrite: The `Body.Blocks` method was returing the blocks in an indefined order, rather than preserving the order of declaration in the source input. ([#313](https://github.com/hashicorp/hcl/pull/313))
* hclwrite: The `TokensForTraversal` function (and thus in turn the `Body.SetAttributeTraversal` method) was not correctly handling index steps in traversals, and thus producing invalid results. ([#319](https://github.com/hashicorp/hcl/pull/319))