Use Span::mixed_site directly from proc-macro2 (#254)

Since 1.0.19, `proc-macro2` now provides `Span::mixed_site` directly.

CHANGELOG.md

@@ -6,6 +6,8 @@
   [#238](https://github.com/lambda-fairy/maud/pull/238)
 - [Changed] Generalize `impl Into<String> for PreEscaped<T>` to `impl From<PreEscaped<T>> for String`.
   [#248](https://github.com/lambda-fairy/maud/pull/248)
+- [Fixed] Use `Span::mixed_site` directly from proc-macro2
+  [#254](https://github.com/lambda-fairy/maud/pull/254)
 
 ## [0.22.1] - 2020-11-02
 

maud_macros/Cargo.toml

@@ -14,7 +14,7 @@ edition = "2018"
 syn = "1.0.8"
 maud_htmlescape = { version = "0.17.0", path = "../maud_htmlescape" }
 quote = "1.0.7"
-proc-macro2 = "1.0.18"
+proc-macro2 = "1.0.19"
 proc-macro-error = "1.0.0"
 
 [lib]

maud_macros/src/lib.rs

@@ -9,7 +9,7 @@ mod ast;
 mod generate;
 mod parse;
 
-use proc_macro2::{Ident, TokenStream, TokenTree};
+use proc_macro2::{Ident, Span, TokenStream, TokenTree};
 use proc_macro_error::proc_macro_error;
 use quote::quote;
 
@@ -28,11 +28,7 @@ pub fn html_debug(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
 }
 
 fn expand(input: TokenStream) -> TokenStream {
-    // TODO: call `proc_macro2::Span::mixed_site()` directly when Rust 1.45 is stable
-    let output_ident = TokenTree::Ident(Ident::new(
-        "__maud_output",
-        proc_macro::Span::mixed_site().into(),
-    ));
+    let output_ident = TokenTree::Ident(Ident::new("__maud_output", Span::mixed_site()));
     // Heuristic: the size of the resulting markup tends to correlate with the
     // code size of the template itself
     let size_hint = input.to_string().len();