diff --git a/src/tests/directives.md b/src/tests/directives.md
index 8e4a7101..4ec2909b 100644
--- a/src/tests/directives.md
+++ b/src/tests/directives.md
@@ -191,8 +191,13 @@ settings:
   specified atomic widths, e.g. the test with `//@ needs-target-has-atomic: 8,
   16, ptr` will only run if it supports the comma-separated list of atomic
   widths.
-- `needs-dynamic-linking` - ignores if target does not support dynamic linking
+- `needs-dynamic-linking` — ignores if target does not support dynamic linking
   (which is orthogonal to it being unable to create `dylib` and `cdylib` crate types)
+- `needs-crate-type` — ignores if target platform does not support one or more
+  of the comma-delimited list of specified crate types. For example,
+  `//@ needs-crate-type: cdylib, proc-macro` will cause the test to be ignored
+  on `wasm32-unknown-unknown` target because the target does not support the
+  `proc-macro` crate type.
 
 The following directives will check LLVM support:
 
@@ -229,14 +234,14 @@ ignoring debuggers.
 
 ### Affecting how tests are built
 
-| Directive           | Explanation                                                                                  | Supported test suites     | Possible values                                                              |
-|---------------------|----------------------------------------------------------------------------------------------|---------------------------|------------------------------------------------------------------------------|
-| `compile-flags`     | Flags passed to `rustc` when building the test or aux file                                   | All except for `run-make` | Any valid `rustc` flags, e.g. `-Awarnings -Dfoo`. Cannot be `-Cincremental`. |
-| `edition`           | Alias for `compile-flags: --edition=xxx`                                                     | All except for `run-make` | Any valid `--edition` value                                                  |
-| `rustc-env`         | Env var to set when running `rustc`                                                          | All except for `run-make` | `<KEY>=<VALUE>`                                                              |
-| `unset-rustc-env`   | Env var to unset when running `rustc`                                                        | All except for `run-make` | Any env var name                                                             |
-| `incremental`       | Proper incremental support for tests outside of incremental test suite                       | `ui`, `crashes`           | N/A                                                                          |
-| `no-prefer-dynamic` | Don't use `-C prefer-dynamic`, don't build as a dylib via a `--crate-type=dylib` preset flag | `ui`, `crashes`           | N/A                                                                          |
+| Directive           | Explanation                                                                                  | Supported test suites     | Possible values                                                                            |
+|---------------------|----------------------------------------------------------------------------------------------|---------------------------|--------------------------------------------------------------------------------------------|
+| `compile-flags`     | Flags passed to `rustc` when building the test or aux file                                   | All except for `run-make` | Any valid `rustc` flags, e.g. `-Awarnings -Dfoo`. Cannot be `-Cincremental` or `--edition` |
+| `edition`           | The edition used to build the test                                                           | All except for `run-make` | Any valid `--edition` value                                                                |
+| `rustc-env`         | Env var to set when running `rustc`                                                          | All except for `run-make` | `<KEY>=<VALUE>`                                                                            |
+| `unset-rustc-env`   | Env var to unset when running `rustc`                                                        | All except for `run-make` | Any env var name                                                                           |
+| `incremental`       | Proper incremental support for tests outside of incremental test suite                       | `ui`, `crashes`           | N/A                                                                                        |
+| `no-prefer-dynamic` | Don't use `-C prefer-dynamic`, don't build as a dylib via a `--crate-type=dylib` preset flag | `ui`, `crashes`           | N/A                                                                                        |
 
 <div class="warning">
 Tests (outside of `run-make`) that want to use incremental tests not in the