Call the right quote from parse_quote on sufficiently new compilers
diff --git a/build.rs b/build.rs
new file mode 100644
index 0000000..51ad927
--- /dev/null
+++ b/build.rs
@@ -0,0 +1,47 @@
+use std::env;
+use std::process::Command;
+use std::str::{self, FromStr};
+
+// The rustc-cfg strings below are *not* public API. Please let us know by
+// opening a GitHub issue if your build environment requires some way to enable
+// these cfgs other than by executing our build script.
+fn main() {
+ let minor = match rustc_minor_version() {
+ Some(minor) => minor,
+ None => return,
+ };
+
+ // Macro modularization allows re-exporting the `quote!` macro in 1.30+.
+ if minor >= 30 {
+ println!("cargo:rustc-cfg=syn_can_call_macro_by_path");
+ }
+}
+
+fn rustc_minor_version() -> Option<u32> {
+ let rustc = match env::var_os("RUSTC") {
+ Some(rustc) => rustc,
+ None => return None,
+ };
+
+ let output = match Command::new(rustc).arg("--version").output() {
+ Ok(output) => output,
+ Err(_) => return None,
+ };
+
+ let version = match str::from_utf8(&output.stdout) {
+ Ok(version) => version,
+ Err(_) => return None,
+ };
+
+ let mut pieces = version.split('.');
+ if pieces.next() != Some("rustc 1") {
+ return None;
+ }
+
+ let next = match pieces.next() {
+ Some(next) => next,
+ None => return None,
+ };
+
+ u32::from_str(next).ok()
+}
diff --git a/src/export.rs b/src/export.rs
index cc7a222..8e270bd 100644
--- a/src/export.rs
+++ b/src/export.rs
@@ -8,6 +8,9 @@
pub use std::option::Option::{None, Some};
pub use std::result::Result::{Err, Ok};
+#[cfg(feature = "printing")]
+pub extern crate quote;
+
pub use proc_macro2::{Span, TokenStream as TokenStream2};
pub use span::IntoSpans;
diff --git a/src/parse_quote.rs b/src/parse_quote.rs
index e7c3dfe..93e2759 100644
--- a/src/parse_quote.rs
+++ b/src/parse_quote.rs
@@ -38,8 +38,14 @@
/// parameter `T` in the input generics.
///
/// ```
-/// #[macro_use]
-/// extern crate quote;
+#[cfg_attr(
+ not(syn_can_call_macro_by_path),
+ doc = " #[macro_use]"
+)]
+#[cfg_attr(
+ not(syn_can_call_macro_by_path),
+ doc = " extern crate quote;"
+)]
/// #[macro_use]
/// extern crate syn;
///
@@ -76,10 +82,29 @@
/// Panics if the tokens fail to parse as the expected syntax tree type. The
/// caller is responsible for ensuring that the input tokens are syntactically
/// valid.
-#[macro_export]
+#[macro_export(local_inner_macros)]
macro_rules! parse_quote {
($($tt:tt)*) => {
- $crate::parse_quote::parse($crate::export::From::from(quote!($($tt)*)))
+ $crate::parse_quote::parse($crate::export::From::from(quote_impl!($($tt)*)))
+ };
+}
+
+#[cfg(not(syn_can_call_macro_by_path))]
+#[doc(hidden)]
+#[macro_export]
+macro_rules! quote_impl {
+ ($($tt:tt)*) => {
+ // Require caller to have their own `#[macro_use] extern crate quote`.
+ quote!($($tt)*)
+ };
+}
+
+#[cfg(syn_can_call_macro_by_path)]
+#[doc(hidden)]
+#[macro_export]
+macro_rules! quote_impl {
+ ($($tt:tt)*) => {
+ $crate::export::quote::quote!($($tt)*)
};
}