From 17b0e93acc16f797837452f07d0da718736afed9 Mon Sep 17 00:00:00 2001
From: BoredApe8416 <letesinkelegesse@gmail.com>
Date: Tue, 19 May 2020 08:56:16 -0700
Subject: [PATCH] Add `Span::mixed_site()` for Rust 1.45+

Fixes #210

This was stabilized in Rust in
https://github.com/rust-lang/rust/pull/68716
---
 build.rs        |  4 ++++
 src/fallback.rs |  5 +++++
 src/lib.rs      | 10 ++++++++++
 src/wrapper.rs  |  9 +++++++++
 4 files changed, 28 insertions(+)

diff --git a/build.rs b/build.rs
index deb9b92..a06f009 100644
--- a/build.rs
+++ b/build.rs
@@ -57,6 +57,10 @@ fn main() {
         println!("cargo:rustc-cfg=span_locations");
     }
 
+    if version.minor >= 45 {
+        println!("cargo:rustc-cfg=hygiene");
+    }
+
     let target = env::var("TARGET").unwrap();
     if !enable_use_proc_macro(&target) {
         return;
diff --git a/src/fallback.rs b/src/fallback.rs
index fffea68..554c87e 100644
--- a/src/fallback.rs
+++ b/src/fallback.rs
@@ -374,6 +374,11 @@ impl Span {
         Span { lo: 0, hi: 0 }
     }
 
+    #[cfg(hygiene)]
+    pub fn mixed_site() -> Span {
+        Span::call_site()
+    }
+
     #[cfg(procmacro2_semver_exempt)]
     pub fn def_site() -> Span {
         Span::call_site()
diff --git a/src/lib.rs b/src/lib.rs
index 23b2c26..725e121 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -348,6 +348,16 @@ impl Span {
         Span::_new(imp::Span::call_site())
     }
 
+    /// The span located at the invocation of the procedural macro, but with
+    /// local variables, labels, and `$crate` resolved at the definition site
+    /// of the macro. This is the same hygiene behavior as `macro_rules`.
+    ///
+    /// This function requires Rust 1.45 or later.
+    #[cfg(hygiene)]
+    pub fn mixed_site() -> Span {
+        Span::_new(imp::Span::mixed_site())
+    }
+
     /// A span that resolves at the macro definition site.
     ///
     /// This method is semver exempt and not exposed by default.
diff --git a/src/wrapper.rs b/src/wrapper.rs
index 1887d8e..f9429b7 100644
--- a/src/wrapper.rs
+++ b/src/wrapper.rs
@@ -376,6 +376,15 @@ impl Span {
         }
     }
 
+    #[cfg(hygiene)]
+    pub fn mixed_site() -> Span {
+        if inside_proc_macro() {
+            Span::Compiler(proc_macro::Span::mixed_site())
+        } else {
+            Span::Fallback(fallback::Span::mixed_site())
+        }
+    }
+
     #[cfg(super_unstable)]
     pub fn def_site() -> Span {
         if inside_proc_macro() {