1 files changed, 145 insertions, 0 deletions
diff --git a/vendor/displaydoc/src/expand.rs b/vendor/displaydoc/src/expand.rs
new file mode 100644
index 000000000..6904cbc8c
--- /dev/null
+++ b/vendor/displaydoc/src/expand.rs
@@ -0,0 +1,145 @@
+use super::attr::AttrsHelper;
+use proc_macro2::TokenStream;
+use quote::{format_ident, quote};
+use syn::{Data, DataEnum, DataStruct, DeriveInput, Error, Fields, Result};
+
+pub(crate) fn derive(input: &DeriveInput) -> Result<TokenStream> {
+    let impls = match &input.data {
+        Data::Struct(data) => impl_struct(input, data),
+        Data::Enum(data) => impl_enum(input, data),
+        Data::Union(_) => Err(Error::new_spanned(input, "Unions are not supported")),
+    }?;
+
+    let helpers = specialization();
+    let dummy_const = format_ident!("_DERIVE_Display_FOR_{}", input.ident);
+    Ok(quote! {
+        #[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
+        const #dummy_const: () = {
+            #helpers
+            #impls
+        };
+    })
+}
+
+#[cfg(feature = "std")]
+fn specialization() -> TokenStream {
+    quote! {
+        trait DisplayToDisplayDoc {
+            fn __displaydoc_display(&self) -> Self;
+        }
+
+        impl<T: core::fmt::Display> DisplayToDisplayDoc for &T {
+            fn __displaydoc_display(&self) -> Self {
+                self
+            }
+        }
+
+        // If the `std` feature gets enabled we want to ensure that any crate
+        // using displaydoc can still reference the std crate, which is already
+        // being compiled in by whoever enabled the `std` feature in
+        // `displaydoc`, even if the crates using displaydoc are no_std.
+        extern crate std;
+
+        trait PathToDisplayDoc {
+            fn __displaydoc_display(&self) -> std::path::Display<'_>;
+        }
+
+        impl PathToDisplayDoc for std::path::Path {
+            fn __displaydoc_display(&self) -> std::path::Display<'_> {
+                self.display()
+            }
+        }
+
+        impl PathToDisplayDoc for std::path::PathBuf {
+            fn __displaydoc_display(&self) -> std::path::Display<'_> {
+                self.display()
+            }
+        }
+    }
+}
+
+#[cfg(not(feature = "std"))]
+fn specialization() -> TokenStream {
+    quote! {}
+}
+
+fn impl_struct(input: &DeriveInput, data: &DataStruct) -> Result<TokenStream> {
+    let ty = &input.ident;
+    let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();
+
+    let helper = AttrsHelper::new(&input.attrs);
+
+    let display = helper.display(&input.attrs)?.map(|display| {
+        let pat = match &data.fields {
+            Fields::Named(fields) => {
+                let var = fields.named.iter().map(|field| &field.ident);
+                quote!(Self { #(#var),* })
+            }
+            Fields::Unnamed(fields) => {
+                let var = (0..fields.unnamed.len()).map(|i| format_ident!("_{}", i));
+                quote!(Self(#(#var),*))
+            }
+            Fields::Unit => quote!(_),
+        };
+        quote! {
+            impl #impl_generics core::fmt::Display for #ty #ty_generics #where_clause {
+                fn fmt(&self, formatter: &mut core::fmt::Formatter) -> core::fmt::Result {
+                    #[allow(unused_variables)]
+                    let #pat = self;
+                    #display
+                }
+            }
+        }
+    });
+
+    Ok(quote! { #display })
+}
+
+fn impl_enum(input: &DeriveInput, data: &DataEnum) -> Result<TokenStream> {
+    let ty = &input.ident;
+    let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();
+
+    let helper = AttrsHelper::new(&input.attrs);
+
+    let displays = data
+        .variants
+        .iter()
+        .map(|variant| helper.display_with_input(&input.attrs, &variant.attrs))
+        .collect::<Result<Vec<_>>>()?;
+
+    if displays.iter().any(Option::is_some) {
+        let arms = data
+            .variants
+            .iter()
+            .zip(displays)
+            .map(|(variant, display)| {
+                let display =
+                    display.ok_or_else(|| Error::new_spanned(variant, "missing doc comment"))?;
+                let ident = &variant.ident;
+                Ok(match &variant.fields {
+                    Fields::Named(fields) => {
+                        let var = fields.named.iter().map(|field| &field.ident);
+                        quote!(#ty::#ident { #(#var),* } => { #display })
+                    }
+                    Fields::Unnamed(fields) => {
+                        let var = (0..fields.unnamed.len()).map(|i| format_ident!("_{}", i));
+                        quote!(#ty::#ident(#(#var),*) => { #display })
+                    }
+                    Fields::Unit => quote!(#ty::#ident => { #display }),
+                })
+            })
+            .collect::<Result<Vec<_>>>()?;
+        Ok(quote! {
+            impl #impl_generics core::fmt::Display for #ty #ty_generics #where_clause {
+                fn fmt(&self, formatter: &mut core::fmt::Formatter) -> core::fmt::Result {
+                    #[allow(unused_variables)]
+                    match self {
+                        #(#arms,)*
+                    }
+                }
+            }
+        })
+    } else {
+        Err(Error::new_spanned(input, "Missing doc comments"))
+    }
+}