Merge pull request #400 from TeXitoi/fix/matches-span

TeXitoi · Jun 12, 2020 · caa1455 · caa1455
2 parents f84e751 + 83894e2
commit caa1455
Showing 1 changed file with 23 additions and 13 deletions.
diff --git a/structopt-derive/src/lib.rs b/structopt-derive/src/lib.rs
@@ -28,7 +28,7 @@ use crate::{
 
 use proc_macro2::{Span, TokenStream};
 use proc_macro_error::{abort, abort_call_site, proc_macro_error, set_dummy};
-use quote::{quote, quote_spanned};
+use quote::{format_ident, quote, quote_spanned};
 use syn::{punctuated::Punctuated, spanned::Spanned, token::Comma, *};
 
 /// Default casing style for generated arguments.
@@ -239,6 +239,16 @@ fn gen_augmentation(
 }
 
 fn gen_constructor(fields: &Punctuated<Field, Comma>, parent_attribute: &Attrs) -> TokenStream {
+    // This ident is used in several match branches below,
+    // and the `quote[_spanned]` invocations have different spans.
+    //
+    // Given that this ident is used in several places and
+    // that the branches are located inside of a loop, it is possible that
+    // this ident will be given _different_ spans in different places, and
+    // thus will not be the _same_ ident anymore. To make sure the `matches`
+    // is always the same, we factor it out.
+    let matches = format_ident!("matches");
+
     let fields = fields.iter().map(|field| {
         let attrs = Attrs::from_field(
             field,
@@ -265,13 +275,13 @@ fn gen_constructor(fields: &Punctuated<Field, Comma>, parent_attribute: &Attrs)
                 };
                 quote_spanned! { kind.span()=>
                     #field_name: <#subcmd_type as ::structopt::StructOptInternal>::from_subcommand(
-                        matches.subcommand())
+                        #matches.subcommand())
                         #unwrapper
                 }
             }
 
             Kind::Flatten => quote_spanned! { kind.span()=>
-                #field_name: ::structopt::StructOpt::from_clap(matches)
+                #field_name: ::structopt::StructOpt::from_clap(#matches)
             },
 
             Kind::Skip(val) => match val {
@@ -318,45 +328,45 @@ fn gen_constructor(fields: &Punctuated<Field, Comma>, parent_attribute: &Attrs)
                 let occurrences = *attrs.parser().kind == ParserKind::FromOccurrences;
                 let name = attrs.cased_name();
                 let field_value = match **ty {
-                    Ty::Bool => quote_spanned!(ty.span()=> matches.is_present(#name)),
+                    Ty::Bool => quote_spanned!(ty.span()=> #matches.is_present(#name)),
 
                     Ty::Option => quote_spanned! { ty.span()=>
-                        matches.#value_of(#name)
+                        #matches.#value_of(#name)
                             .map(#parse)
                     },
 
                     Ty::OptionOption => quote_spanned! { ty.span()=>
-                        if matches.is_present(#name) {
-                            Some(matches.#value_of(#name).map(#parse))
+                        if #matches.is_present(#name) {
+                            Some(#matches.#value_of(#name).map(#parse))
                         } else {
                             None
                         }
                     },
 
                     Ty::OptionVec => quote_spanned! { ty.span()=>
-                        if matches.is_present(#name) {
-                            Some(matches.#values_of(#name)
+                        if #matches.is_present(#name) {
+                            Some(#matches.#values_of(#name)
                                  .map_or_else(Vec::new, |v| v.map(#parse).collect()))
                         } else {
                             None
                         }
                     },
 
                     Ty::Vec => quote_spanned! { ty.span()=>
-                        matches.#values_of(#name)
+                        #matches.#values_of(#name)
                             .map_or_else(Vec::new, |v| v.map(#parse).collect())
                     },
 
                     Ty::Other if occurrences => quote_spanned! { ty.span()=>
-                        #parse(matches.#value_of(#name))
+                        #parse(#matches.#value_of(#name))
                     },
 
                     Ty::Other if flag => quote_spanned! { ty.span()=>
-                        #parse(matches.is_present(#name))
+                        #parse(#matches.is_present(#name))
                     },
 
                     Ty::Other => quote_spanned! { ty.span()=>
-                        matches.#value_of(#name)
+                        #matches.#value_of(#name)
                             .map(#parse)
                             .unwrap()
                     },