Change Binding::Location to a struct-style enum variant.

This commit makes no other changes. This is in preparation for adding a third
field, at which point tuple variants start to get obscure.

src/back/glsl/features.rs

@@ -288,7 +288,10 @@ impl<'a, W> Writer<'a, W> {
                 }
             }
             _ => {
-                if let Some(&Binding::Location(_, Some(interpolation))) = binding {
+                if let Some(&Binding::Location {
+                    interpolation: Some(interpolation),
+                    ..
+                }) = binding {
                     match interpolation {
                         Interpolation::Linear => {
                             self.features.request(Features::NOPERSPECTIVE_QUALIFIER)

src/back/glsl/mod.rs

@@ -242,7 +242,7 @@ struct VaryingName<'a> {
 impl fmt::Display for VaryingName<'_> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match *self.binding {
-            Binding::Location(location, _) => {
+            Binding::Location { location, .. } => {
                 let prefix = match (self.stage, self.output) {
                     (ShaderStage::Compute, _) => unreachable!(),
                     // pipeline to vertex
@@ -794,7 +794,7 @@ impl<'a, W: Write> Writer<'a, W> {
             }
             _ => {
                 let (location, interpolation) = match binding {
-                    Some(&Binding::Location(location, interpolation)) => (location, interpolation),
+                    Some(&Binding::Location { location, interpolation }) => (location, interpolation),
                     _ => return Ok(()),
                 };
                 // Write the interpolation modifier if needed
@@ -825,7 +825,7 @@ impl<'a, W: Write> Writer<'a, W> {
                 // Finally write the global name and end the global with a `;` and a newline
                 // Leading space is important
                 let vname = VaryingName {
-                    binding: &Binding::Location(location, None),
+                    binding: &Binding::Location { location, interpolation: None },
                     stage: self.entry_point.stage,
                     output,
                 };

src/back/msl/mod.rs

@@ -183,21 +183,21 @@ impl Options {
     ) -> Result<ResolvedBinding, Error> {
         match *binding {
             crate::Binding::BuiltIn(built_in) => Ok(ResolvedBinding::BuiltIn(built_in)),
-            crate::Binding::Location(index, _) => match mode {
-                LocationMode::VertexInput => Ok(ResolvedBinding::Attribute(index)),
-                LocationMode::FragmentOutput => Ok(ResolvedBinding::Color(index)),
+            crate::Binding::Location { location, .. } => match mode {
+                LocationMode::VertexInput => Ok(ResolvedBinding::Attribute(location)),
+                LocationMode::FragmentOutput => Ok(ResolvedBinding::Color(location)),
                 LocationMode::Intermediate => Ok(ResolvedBinding::User {
                     prefix: if self.spirv_cross_compatibility {
                         "locn"
                     } else {
                         "loc"
                     },
-                    index,
+                    index: location,
                 }),
                 LocationMode::Uniform => {
                     log::error!(
                         "Unexpected Binding::Location({}) for the Uniform mode",
-                        index
+                        location
                     );
                     Err(Error::Validation)
                 }

src/back/msl/writer.rs

@@ -1821,7 +1821,7 @@ impl<W: Write> Writer<W> {
                 writeln!(self.out, "struct {} {{", stage_in_name)?;
                 for &(ref name_key, ty, binding) in argument_members.iter() {
                     let binding = match binding {
-                        Some(ref binding @ &crate::Binding::Location(..)) => binding,
+                        Some(ref binding @ &crate::Binding::Location { .. }) => binding,
                         _ => continue,
                     };
                     varying_count += 1;
@@ -2044,7 +2044,7 @@ impl<W: Write> Writer<W> {
                             if member_index != 0 {
                                 write!(self.out, ", ")?;
                             }
-                            if let Some(crate::Binding::Location(..)) = member.binding {
+                            if let Some(crate::Binding::Location { .. }) = member.binding {
                                 write!(self.out, "{}.", varyings_member_name)?;
                             }
                             write!(self.out, "{}", name)?;
@@ -2052,7 +2052,7 @@ impl<W: Write> Writer<W> {
                         writeln!(self.out, " }};")?;
                     }
                     _ => {
-                        if let Some(crate::Binding::Location(..)) = arg.binding {
+                        if let Some(crate::Binding::Location { .. }) = arg.binding {
                             writeln!(
                                 self.out,
                                 "{}const auto {} = {}.{};",

src/back/spv/writer.rs

@@ -1090,7 +1090,7 @@ impl Writer {
         use spirv::{BuiltIn, Decoration};
 
         match *binding {
-            crate::Binding::Location(location, interpolation) => {
+            crate::Binding::Location { location, interpolation } => {
                 self.decorate(id, Decoration::Location, &[location]);
                 let interp_decoration = match interpolation {
                     Some(crate::Interpolation::Linear) => Some(Decoration::NoPerspective),

src/front/glsl/parser.rs

@@ -614,9 +614,9 @@ pomelo! {
     }
 
     layout_qualifier ::= Layout LeftParen layout_qualifier_id_list(l) RightParen {
-        if let Some(&(_, loc)) = l.iter().find(|&q| q.0.as_str() == "location") {
+        if let Some(&(_, location)) = l.iter().find(|&q| q.0.as_str() == "location") {
             let interpolation = None; //TODO
-            StructLayout::Binding(Binding::Location(loc, interpolation))
+            StructLayout::Binding(Binding::Location { location, interpolation })
         } else if let Some(&(_, binding)) = l.iter().find(|&q| q.0.as_str() == "binding") {
             let group = if let Some(&(_, set)) = l.iter().find(|&q| q.0.as_str() == "set") {
                 set
@@ -1133,7 +1133,7 @@ pomelo! {
                     let interpolation = d.type_qualifiers.iter().find_map(|tq| {
                         if let TypeQualifier::Interpolation(interp) = *tq { Some(interp) } else { None }
                     });
-                    if let Some(Binding::Location(_, ref mut interp)) = binding {
+                    if let Some(Binding::Location { interpolation: ref mut interp, .. }) = binding {
                         *interp = interpolation;
                     }
 

src/front/spv/function.rs

@@ -213,9 +213,10 @@ impl<I: Iterator<Item = u32>> super::Parser<I> {
                     });
                     let mut arg = arg.clone();
                     if ep.stage == crate::ShaderStage::Fragment {
-                        if let Some(crate::Binding::Location(_, ref mut interpolation @ None)) =
-                            arg.binding
-                        {
+                        if let Some(crate::Binding::Location {
+                            interpolation: ref mut interpolation @ None,
+                            ..
+                        }) = arg.binding {
                             *interpolation = Some(crate::Interpolation::Perspective);
                             // default
                         }

src/front/spv/mod.rs

@@ -251,10 +251,10 @@ impl Decoration {
             } => map_builtin(built_in).map(crate::Binding::BuiltIn),
             Decoration {
                 built_in: None,
-                location: Some(loc),
+                location: Some(location),
                 interpolation,
                 ..
-            } => Ok(crate::Binding::Location(loc, interpolation)),
+            } => Ok(crate::Binding::Location { location, interpolation }),
             _ => Err(Error::MissingDecoration(spirv::Decoration::Location)),
         }
     }

src/front/wgsl/mod.rs

@@ -500,8 +500,8 @@ impl BindingParser {
     fn finish<'a>(self) -> Result<Option<crate::Binding>, Error<'a>> {
         match (self.location, self.built_in, self.interpolation) {
             (None, None, None) => Ok(None),
-            (Some(loc), None, interpolation) => {
-                Ok(Some(crate::Binding::Location(loc, interpolation)))
+            (Some(location), None, interpolation) => {
+                Ok(Some(crate::Binding::Location { location, interpolation }))
             }
             (None, Some(bi), None) => Ok(Some(crate::Binding::BuiltIn(bi))),
             (location, built_in, interpolation) => Err(Error::InconsistentBinding(

src/lib.rs

@@ -465,7 +465,7 @@ pub enum Binding {
     /// Built-in shader variable.
     BuiltIn(BuiltIn),
     /// Indexed location.
-    Location(u32, Option<Interpolation>),
+    Location { location: u32, interpolation: Option<Interpolation> },
 }
 
 /// Pipeline binding information for global resources.

src/proc/mod.rs

@@ -212,7 +212,7 @@ impl crate::Binding {
     pub fn to_built_in(&self) -> Option<crate::BuiltIn> {
         match *self {
             Self::BuiltIn(bi) => Some(bi),
-            Self::Location(..) => None,
+            Self::Location { .. } => None,
         }
     }
 }

src/valid/analyzer.rs

@@ -344,7 +344,10 @@ impl FunctionInfo {
                         _ => false,
                     },
                     // only flat inputs are uniform
-                    Some(crate::Binding::Location(_, Some(crate::Interpolation::Flat))) => true,
+                    Some(crate::Binding::Location {
+                        interpolation: Some(crate::Interpolation::Flat),
+                        ..
+                    }) => true,
                     _ => false,
                 };
                 Uniformity {

src/valid/interface.rs

@@ -206,7 +206,7 @@ impl VaryingContext<'_> {
                     return Err(VaryingError::InvalidBuiltInType(built_in));
                 }
             }
-            crate::Binding::Location(location, interpolation) => {
+            crate::Binding::Location { location, interpolation } => {
                 if !self.location_mask.insert(location as usize) {
                     return Err(VaryingError::BindingCollision { location });
                 }

tests/out/shadow.ron

@@ -1517,17 +1517,26 @@
                     (
                         name: Some("in_normal_fs"),
                         ty: 2,
-                        binding: Some(Location(0, Some(Perspective))),
+                        binding: Some(Location(
+                            location: 0,
+                            interpolation: Some(Perspective),
+                        )),
                     ),
                     (
                         name: Some("in_position_fs"),
                         ty: 4,
-                        binding: Some(Location(1, Some(Perspective))),
+                        binding: Some(Location(
+                            location: 1,
+                            interpolation: Some(Perspective),
+                        )),
                     ),
                 ],
                 result: Some((
                     ty: 4,
-                    binding: Some(Location(0, None)),
+                    binding: Some(Location(
+                        location: 0,
+                        interpolation: None,
+                    )),
                 )),
                 local_variables: [],
                 expressions: [