Make use of new language features (#1841)

* use strip_prefix

* make fn const (resolving TODO)

* make use of nested OR patterns in match arms

* warn on clippy::missing_const_for_fn

* constify functions

* ignore clippy::missing_const_for_fn for into_inner functions

cli/src/main.rs

@@ -288,7 +288,7 @@ fn run() -> Result<(), Box<dyn std::error::Error>> {
                 }
             }
         }
-        ext @ "vert" | ext @ "frag" | ext @ "comp" => {
+        ext @ ("vert" | "frag" | "comp") => {
             let input = String::from_utf8(input)?;
             let mut parser = naga::front::glsl::Parser::default();
 
@@ -429,7 +429,7 @@ fn run() -> Result<(), Box<dyn std::error::Error>> {
 
                 fs::write(output_path, bytes.as_slice())?;
             }
-            stage @ "vert" | stage @ "frag" | stage @ "comp" => {
+            stage @ ("vert" | "frag" | "comp") => {
                 use naga::back::glsl;
 
                 let pipeline_options = glsl::PipelineOptions {

src/arena.rs

@@ -81,15 +81,15 @@ impl<T> Handle<T> {
         marker: PhantomData,
     };
 
-    pub(crate) fn new(index: Index) -> Self {
+    pub(crate) const fn new(index: Index) -> Self {
         Handle {
             index,
             marker: PhantomData,
         }
     }
 
     /// Returns the zero-based index of this handle.
-    pub fn index(self) -> usize {
+    pub const fn index(self) -> usize {
         let index = self.index.get() - 1;
         index as usize
     }
@@ -106,7 +106,7 @@ impl<T> Handle<T> {
     }
 
     /// Convert a `usize` index into a `Handle<T>`, without range checks.
-    unsafe fn from_usize_unchecked(index: usize) -> Self {
+    const unsafe fn from_usize_unchecked(index: usize) -> Self {
         Handle::new(Index::new_unchecked((index + 1) as u32))
     }
 }
@@ -187,7 +187,7 @@ impl<T: fmt::Debug> fmt::Debug for Arena<T> {
 
 impl<T> Arena<T> {
     /// Create a new arena with no initial capacity allocated.
-    pub fn new() -> Self {
+    pub const fn new() -> Self {
         Arena {
             data: Vec::new(),
             #[cfg(feature = "span")]
@@ -196,6 +196,7 @@ impl<T> Arena<T> {
     }
 
     /// Extracts the inner vector.
+    #[allow(clippy::missing_const_for_fn)] // ignore due to requirement of #![feature(const_precise_live_drops)]
     pub fn into_inner(self) -> Vec<T> {
         self.data
     }

src/back/glsl/features.rs

@@ -47,7 +47,7 @@ pub struct FeaturesManager(Features);
 
 impl FeaturesManager {
     /// Creates a new [`FeaturesManager`] instance
-    pub fn new() -> Self {
+    pub const fn new() -> Self {
         Self(Features::empty())
     }
 

src/back/glsl/mod.rs

@@ -73,7 +73,7 @@ pub const SUPPORTED_ES_VERSIONS: &[u16] = &[300, 310, 320];
 pub type BindingMap = std::collections::BTreeMap<crate::ResourceBinding, u8>;
 
 impl crate::AtomicFunction {
-    fn to_glsl(self) -> &'static str {
+    const fn to_glsl(self) -> &'static str {
         match self {
             Self::Add | Self::Subtract => "Add",
             Self::And => "And",
@@ -88,15 +88,15 @@ impl crate::AtomicFunction {
 }
 
 impl crate::AddressSpace {
-    fn is_buffer(&self) -> bool {
+    const fn is_buffer(&self) -> bool {
         match *self {
             crate::AddressSpace::Uniform | crate::AddressSpace::Storage { .. } => true,
             _ => false,
         }
     }
 
     /// Whether a variable with this address space can be initialized
-    fn initializable(&self) -> bool {
+    const fn initializable(&self) -> bool {
         match *self {
             crate::AddressSpace::Function | crate::AddressSpace::Private => true,
             crate::AddressSpace::WorkGroup
@@ -121,7 +121,7 @@ pub enum Version {
 
 impl Version {
     /// Returns true if self is `Version::Embedded` (i.e. is a es version)
-    fn is_es(&self) -> bool {
+    const fn is_es(&self) -> bool {
         match *self {
             Version::Desktop(_) => false,
             Version::Embedded(_) => true,
@@ -306,7 +306,7 @@ impl fmt::Display for VaryingName<'_> {
 }
 
 impl ShaderStage {
-    fn to_str(self) -> &'static str {
+    const fn to_str(self) -> &'static str {
         match self {
             ShaderStage::Compute => "cs",
             ShaderStage::Fragment => "fs",
@@ -3153,7 +3153,7 @@ struct ScalarString<'a> {
 ///
 /// # Errors
 /// If a [`Float`](crate::ScalarKind::Float) with an width that isn't 4 or 8
-fn glsl_scalar(
+const fn glsl_scalar(
     kind: crate::ScalarKind,
     width: crate::Bytes,
 ) -> Result<ScalarString<'static>, Error> {
@@ -3187,7 +3187,7 @@ fn glsl_scalar(
 }
 
 /// Helper function that returns the glsl variable name for a builtin
-fn glsl_built_in(built_in: crate::BuiltIn, output: bool) -> &'static str {
+const fn glsl_built_in(built_in: crate::BuiltIn, output: bool) -> &'static str {
     use crate::BuiltIn as Bi;
 
     match built_in {
@@ -3230,7 +3230,7 @@ fn glsl_built_in(built_in: crate::BuiltIn, output: bool) -> &'static str {
 }
 
 /// Helper function that returns the string corresponding to the address space
-fn glsl_storage_qualifier(space: crate::AddressSpace) -> Option<&'static str> {
+const fn glsl_storage_qualifier(space: crate::AddressSpace) -> Option<&'static str> {
     use crate::AddressSpace as As;
 
     match space {
@@ -3245,7 +3245,7 @@ fn glsl_storage_qualifier(space: crate::AddressSpace) -> Option<&'static str> {
 }
 
 /// Helper function that returns the string corresponding to the glsl interpolation qualifier
-fn glsl_interpolation(interpolation: crate::Interpolation) -> &'static str {
+const fn glsl_interpolation(interpolation: crate::Interpolation) -> &'static str {
     use crate::Interpolation as I;
 
     match interpolation {
@@ -3256,7 +3256,7 @@ fn glsl_interpolation(interpolation: crate::Interpolation) -> &'static str {
 }
 
 /// Return the GLSL auxiliary qualifier for the given sampling value.
-fn glsl_sampling(sampling: crate::Sampling) -> Option<&'static str> {
+const fn glsl_sampling(sampling: crate::Sampling) -> Option<&'static str> {
     use crate::Sampling as S;
 
     match sampling {
@@ -3267,7 +3267,7 @@ fn glsl_sampling(sampling: crate::Sampling) -> Option<&'static str> {
 }
 
 /// Helper function that returns the glsl dimension string of [`ImageDimension`](crate::ImageDimension)
-fn glsl_dimension(dim: crate::ImageDimension) -> &'static str {
+const fn glsl_dimension(dim: crate::ImageDimension) -> &'static str {
     use crate::ImageDimension as IDim;
 
     match dim {
@@ -3279,7 +3279,7 @@ fn glsl_dimension(dim: crate::ImageDimension) -> &'static str {
 }
 
 /// Helper function that returns the glsl storage format string of [`StorageFormat`](crate::StorageFormat)
-fn glsl_storage_format(format: crate::StorageFormat) -> &'static str {
+const fn glsl_storage_format(format: crate::StorageFormat) -> &'static str {
     use crate::StorageFormat as Sf;
 
     match format {

src/back/hlsl/conv.rs

@@ -15,7 +15,7 @@ impl crate::ScalarKind {
     /// Helper function that returns scalar related strings
     ///
     /// <https://docs.microsoft.com/en-us/windows/win32/direct3dhlsl/dx-graphics-hlsl-scalar>
-    pub(super) fn to_hlsl_str(self, width: crate::Bytes) -> Result<&'static str, Error> {
+    pub(super) const fn to_hlsl_str(self, width: crate::Bytes) -> Result<&'static str, Error> {
         match self {
             Self::Sint => Ok("int"),
             Self::Uint => Ok("uint"),
@@ -31,7 +31,7 @@ impl crate::ScalarKind {
 }
 
 impl crate::TypeInner {
-    pub(super) fn is_matrix(&self) -> bool {
+    pub(super) const fn is_matrix(&self) -> bool {
         match *self {
             Self::Matrix { .. } => true,
             _ => false,
@@ -113,7 +113,7 @@ impl crate::TypeInner {
 }
 
 impl crate::StorageFormat {
-    pub(super) fn to_hlsl_str(self) -> &'static str {
+    pub(super) const fn to_hlsl_str(self) -> &'static str {
         match self {
             Self::R16Float => "float",
             Self::R8Unorm => "unorm float",
@@ -187,7 +187,7 @@ impl crate::BuiltIn {
 
 impl crate::Interpolation {
     /// Return the string corresponding to the HLSL interpolation qualifier.
-    pub(super) fn to_hlsl_str(self) -> Option<&'static str> {
+    pub(super) const fn to_hlsl_str(self) -> Option<&'static str> {
         match self {
             // Would be "linear", but it's the default interpolation in SM4 and up
             // https://docs.microsoft.com/en-us/windows/win32/direct3dhlsl/dx-graphics-hlsl-struct#interpolation-modifiers-introduced-in-shader-model-4
@@ -200,7 +200,7 @@ impl crate::Interpolation {
 
 impl crate::Sampling {
     /// Return the HLSL auxiliary qualifier for the given sampling value.
-    pub(super) fn to_hlsl_str(self) -> Option<&'static str> {
+    pub(super) const fn to_hlsl_str(self) -> Option<&'static str> {
         match self {
             Self::Center => None,
             Self::Centroid => Some("centroid"),
@@ -211,7 +211,7 @@ impl crate::Sampling {
 
 impl crate::AtomicFunction {
     /// Return the HLSL suffix for the `InterlockedXxx` method.
-    pub(super) fn to_hlsl_suffix(self) -> &'static str {
+    pub(super) const fn to_hlsl_suffix(self) -> &'static str {
         match self {
             Self::Add | Self::Subtract => "Add",
             Self::And => "And",

src/back/hlsl/mod.rs

@@ -65,7 +65,7 @@ pub enum ShaderModel {
 }
 
 impl ShaderModel {
-    pub fn to_str(self) -> &'static str {
+    pub const fn to_str(self) -> &'static str {
         match self {
             Self::V5_0 => "5_0",
             Self::V5_1 => "5_1",
@@ -75,7 +75,7 @@ impl ShaderModel {
 }
 
 impl crate::ShaderStage {
-    pub fn to_hlsl_str(self) -> &'static str {
+    pub const fn to_hlsl_str(self) -> &'static str {
         match self {
             Self::Vertex => "vs",
             Self::Fragment => "ps",
@@ -85,7 +85,7 @@ impl crate::ShaderStage {
 }
 
 impl crate::ImageDimension {
-    fn to_hlsl_str(self) -> &'static str {
+    const fn to_hlsl_str(self) -> &'static str {
         match self {
             Self::D1 => "1D",
             Self::D2 => "2D",

src/back/hlsl/writer.rs

@@ -57,7 +57,7 @@ enum InterfaceKey {
 }
 
 impl InterfaceKey {
-    fn new(binding: Option<&crate::Binding>) -> Self {
+    const fn new(binding: Option<&crate::Binding>) -> Self {
         match binding {
             Some(&crate::Binding::Location { location, .. }) => Self::Location(location),
             Some(&crate::Binding::BuiltIn(built_in)) => Self::BuiltIn(built_in),

src/back/mod.rs

@@ -26,7 +26,7 @@ type NeedBakeExpressions = crate::FastHashSet<crate::Handle<crate::Expression>>;
 struct Level(usize);
 
 impl Level {
-    fn next(&self) -> Self {
+    const fn next(&self) -> Self {
         Level(self.0 + 1)
     }
 }
@@ -61,7 +61,7 @@ struct FunctionCtx<'a> {
 
 impl<'a> FunctionCtx<'_> {
     /// Helper method that generates a [`NameKey`](crate::proc::NameKey) for a local in the current function
-    fn name_key(&self, local: crate::Handle<crate::LocalVariable>) -> crate::proc::NameKey {
+    const fn name_key(&self, local: crate::Handle<crate::LocalVariable>) -> crate::proc::NameKey {
         match self.ty {
             FunctionType::Function(handle) => crate::proc::NameKey::FunctionLocal(handle, local),
             FunctionType::EntryPoint(idx) => crate::proc::NameKey::EntryPointLocal(idx, local),
@@ -72,7 +72,7 @@ impl<'a> FunctionCtx<'_> {
     ///
     /// # Panics
     /// - If the function arguments are less or equal to `arg`
-    fn argument_key(&self, arg: u32) -> crate::proc::NameKey {
+    const fn argument_key(&self, arg: u32) -> crate::proc::NameKey {
         match self.ty {
             FunctionType::Function(handle) => crate::proc::NameKey::FunctionArgument(handle, arg),
             FunctionType::EntryPoint(ep_index) => {
@@ -128,7 +128,7 @@ impl crate::Expression {
     /// See the [module-level documentation][emit] for details.
     ///
     /// [emit]: index.html#expression-evaluation-time
-    fn bake_ref_count(&self) -> usize {
+    const fn bake_ref_count(&self) -> usize {
         match *self {
             // accesses are never cached, only loads are
             crate::Expression::Access { .. } | crate::Expression::AccessIndex { .. } => !0,
@@ -149,7 +149,7 @@ impl crate::Expression {
 /// Helper function that returns the string corresponding to the [`BinaryOperator`](crate::BinaryOperator)
 /// # Notes
 /// Used by `glsl-out`, `msl-out`, `wgsl-out`, `hlsl-out`.
-fn binary_operation_str(op: crate::BinaryOperator) -> &'static str {
+const fn binary_operation_str(op: crate::BinaryOperator) -> &'static str {
     use crate::BinaryOperator as Bo;
     match op {
         Bo::Add => "+",
@@ -176,7 +176,7 @@ fn binary_operation_str(op: crate::BinaryOperator) -> &'static str {
 /// Helper function that returns the string corresponding to the [`VectorSize`](crate::VectorSize)
 /// # Notes
 /// Used by `msl-out`, `wgsl-out`, `hlsl-out`.
-fn vector_size_str(size: crate::VectorSize) -> &'static str {
+const fn vector_size_str(size: crate::VectorSize) -> &'static str {
     match size {
         crate::VectorSize::Bi => "2",
         crate::VectorSize::Tri => "3",
@@ -185,7 +185,7 @@ fn vector_size_str(size: crate::VectorSize) -> &'static str {
 }
 
 impl crate::TypeInner {
-    fn is_handle(&self) -> bool {
+    const fn is_handle(&self) -> bool {
         match *self {
             crate::TypeInner::Image { .. } | crate::TypeInner::Sampler { .. } => true,
             _ => false,
@@ -197,7 +197,7 @@ impl crate::Statement {
     /// Returns true if the statement directly terminates the current block.
     ///
     /// Used to decide whether case blocks require a explicit `break`.
-    pub fn is_terminator(&self) -> bool {
+    pub const fn is_terminator(&self) -> bool {
         match *self {
             crate::Statement::Break
             | crate::Statement::Continue

src/back/msl/mod.rs

@@ -305,7 +305,7 @@ impl Options {
         }
     }
 
-    fn resolve_push_constants(
+    const fn resolve_push_constants(
         &self,
         stage: crate::ShaderStage,
     ) -> Result<ResolvedBinding, EntryPointError> {
@@ -428,7 +428,7 @@ impl ResolvedBinding {
 }
 
 impl ResolvedInterpolation {
-    fn from_binding(interpolation: crate::Interpolation, sampling: crate::Sampling) -> Self {
+    const fn from_binding(interpolation: crate::Interpolation, sampling: crate::Sampling) -> Self {
         use crate::Interpolation as I;
         use crate::Sampling as S;