Merge #103

103: Use Generics::make_where_clause helper r=Ogeon a=dtolnay The [`Generics::make_where_clause`](https://docs.rs/syn/0.14/syn/struct.Generics.html#method.make_where_clause) method initializes an empty where-clause if there is not one present already, similar to palette_derive's `add_missing_where_clause`. This eliminates a handful of `unwrap` calls that can never fail. Co-authored-by: David Tolnay <[email protected]>
Ogeon · May 26, 2018 · 8f9634c · 8f9634c
2 parents 981ba25 + 92fb072
commit 8f9634c
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Showing 4 changed files with 14 additions and 34 deletions.
diff --git a/palette_derive/src/convert/from_color.rs b/palette_derive/src/convert/from_color.rs
@@ -572,9 +572,8 @@ fn prepare_from_color_type_impl(
             rgb_space.clone()
         } else {
             let rgb_space_path = util::path(&["rgb", "RgbSpace"], meta.internal);
-            util::add_missing_where_clause(&mut generics);
-            let where_clause = generics.where_clause.as_mut().unwrap();
-            where_clause
+            generics
+                .make_where_clause()
                 .predicates
                 .push(parse_quote!(_S: #rgb_space_path<WhitePoint = #white_point>));
 

diff --git a/palette_derive/src/convert/into_color.rs b/palette_derive/src/convert/into_color.rs
@@ -365,9 +365,8 @@ fn prepare_into_color_type_impl(
             rgb_space.clone()
         } else {
             let rgb_space_path = util::path(&["rgb", "RgbSpace"], meta.internal);
-            util::add_missing_where_clause(&mut generics);
-            let where_clause = generics.where_clause.as_mut().unwrap();
-            where_clause
+            generics
+                .make_where_clause()
                 .predicates
                 .push(parse_quote!(_S: #rgb_space_path<WhitePoint = #white_point>));
 

diff --git a/palette_derive/src/convert/shared.rs b/palette_derive/src/convert/shared.rs
@@ -77,23 +77,19 @@ pub fn rgb_space_type(rgb_space: Option<Type>, white_point: &Type, internal: boo
 }
 
 pub fn add_component_where_clause(component: &Type, generics: &mut Generics, internal: bool) {
-    util::add_missing_where_clause(generics);
-
-    let where_clause = generics.where_clause.as_mut().unwrap();
     let component_trait_path = util::path(&["Component"], internal);
 
-    where_clause
+    generics
+        .make_where_clause()
         .predicates
         .push(parse_quote!(#component: #component_trait_path + _num_traits::Float));
 }
 
 pub fn add_white_point_where_clause(white_point: &Type, generics: &mut Generics, internal: bool) {
-    util::add_missing_where_clause(generics);
-
-    let where_clause = generics.where_clause.as_mut().unwrap();
     let white_point_trait_path = util::path(&["white_point", "WhitePoint"], internal);
 
-    where_clause
+    generics
+        .make_where_clause()
         .predicates
         .push(parse_quote!(#white_point: #white_point_trait_path));
 }
@@ -235,8 +231,7 @@ pub fn get_convert_color_type(
                 Ident::new("_S", Span::call_site()).into(),
             ));
 
-            util::add_missing_where_clause(generics);
-            let where_clause = generics.where_clause.as_mut().unwrap();
+            let where_clause = generics.make_where_clause();
             if let Some(ref rgb_space) = rgb_space {
                 where_clause
                     .predicates
@@ -258,27 +253,24 @@ pub fn get_convert_color_type(
                 Ident::new("_S", Span::call_site()).into(),
             ));
 
-            util::add_missing_where_clause(generics);
-            let where_clause = generics.where_clause.as_mut().unwrap();
-            where_clause
+            generics
+                .make_where_clause()
                 .predicates
                 .push(parse_quote!(_S: #luma_standard_path<WhitePoint = #white_point>));
             parse_quote!(#color_path<_S, #component>)
         }
         "Hsl" | "Hsv" | "Hwb" => {
             let rgb_space_path = util::path(&["rgb", "RgbSpace"], internal);
 
-            util::add_missing_where_clause(generics);
-
             if let Some(ref rgb_space) = rgb_space {
                 parse_quote!(#color_path<#rgb_space, #component>)
             } else {
                 generics.params.push(GenericParam::Type(
                     Ident::new("_S", Span::call_site()).into(),
                 ));
 
-                let where_clause = generics.where_clause.as_mut().unwrap();
-                where_clause
+                generics
+                    .make_where_clause()
                     .predicates
                     .push(parse_quote!(_S: #rgb_space_path<WhitePoint = #white_point>));
 

diff --git a/palette_derive/src/util.rs b/palette_derive/src/util.rs
@@ -1,6 +1,5 @@
 use proc_macro2::{Span, TokenStream};
-use syn::punctuated::Punctuated;
-use syn::{Generics, Ident, Type, WhereClause};
+use syn::{Ident, Type};
 
 pub fn bundle_impl(
     trait_name: &str,
@@ -66,12 +65,3 @@ pub fn color_path(color: &str, internal: bool) -> TokenStream {
         _ => path(&[color], internal),
     }
 }
-
-pub fn add_missing_where_clause(generics: &mut Generics) {
-    if generics.where_clause.is_none() {
-        generics.where_clause = Some(WhereClause {
-            where_token: Token![where](Span::call_site()),
-            predicates: Punctuated::new(),
-        })
-    }
-}