From 9fa60a75964dddc59ac36544db2788c8b983778f Mon Sep 17 00:00:00 2001
From: p0lunin <dmytro.polunin@gmail.com>
Date: Wed, 24 Jun 2020 19:13:56 +0300
Subject: [PATCH] fixed rust could not infer types

---
 src/fields_parse.rs | 33 ++++++++++++++++-----------------
 1 file changed, 16 insertions(+), 17 deletions(-)

diff --git a/src/fields_parse.rs b/src/fields_parse.rs
index 3b38c38f..163b4f4e 100644
--- a/src/fields_parse.rs
+++ b/src/fields_parse.rs
@@ -2,7 +2,7 @@ extern crate quote;
 
 use quote::__private::Span;
 use quote::{quote, ToTokens};
-use syn::{FieldsNamed, FieldsUnnamed};
+use syn::{FieldsNamed, FieldsUnnamed, Type};
 
 #[derive(Debug)]
 pub enum ParserType {
@@ -26,7 +26,7 @@ pub fn impl_parse_args_unnamed(
     variant: impl ToTokens,
     parser_type: &ParserType,
 ) -> quote::__private::TokenStream {
-    let get_arguments = create_parser(parser_type, data.unnamed.len());
+    let get_arguments = create_parser(parser_type, data.unnamed.iter().map(|f| &f.ty), data.unnamed.len());
     let iter = 0..data.unnamed.len();
     let mut initialization = quote! {};
     for i in iter {
@@ -46,7 +46,7 @@ pub fn impl_parse_args_named(
     variant: impl ToTokens,
     parser_type: &ParserType,
 ) -> quote::__private::TokenStream {
-    let get_arguments = create_parser(parser_type, data.named.len());
+    let get_arguments = create_parser(parser_type, data.named.iter().map(|f| &f.ty), data.named.len());
     let i = 0..data.named.len();
     let name = data.named.iter().map(|f| f.ident.as_ref().unwrap());
     let res = quote! {
@@ -58,16 +58,16 @@ pub fn impl_parse_args_named(
     res
 }
 
-fn create_parser(parser_type: &ParserType, count_args: usize) -> quote::__private::TokenStream {
+fn create_parser<'a>(parser_type: &ParserType, types: impl Iterator<Item = &'a Type>, count_args: usize) -> quote::__private::TokenStream {
     let function_to_parse = match parser_type {
         ParserType::Default => match count_args {
             1 => {
-                quote! { (|s: String| Ok((FromStr::from_str(&s).map_err(|_|ParseError::IncorrectFormat)?,)) ) }
+                quote! { (|s: String| Ok((s,))) }
             }
             _ => quote! { compile_error!("Expected 1 argument") },
         },
         ParserType::Split { separator } => {
-            parser_with_separator(&separator.clone().unwrap_or(" ".to_owned()), count_args)
+            parser_with_separator(&separator.clone().unwrap_or(" ".to_owned()), types, count_args)
         }
         ParserType::Custom(s) => {
             let ident = syn::Ident::new(&s, Span::call_site());
@@ -79,18 +79,17 @@ fn create_parser(parser_type: &ParserType, count_args: usize) -> quote::__privat
     }
 }
 
-fn parser_with_separator(separator: &str, count_args: usize) -> quote::__private::TokenStream {
+fn parser_with_separator<'a>(separator: &str, types: impl Iterator<Item = &'a Type>, count_args: usize) -> quote::__private::TokenStream {
     let inner = quote! { let mut splited = s.split(#separator); };
-    let mut inner2 = quote! {};
-    for i in 0..count_args {
-        inner2.extend(
-            quote! { FromStr::from_str(splited.next().ok_or(ParseError::TooFewArguments {
-                expected: #count_args,
-                found: #i,
-                message: format!("Expected but not found arg number {}", #i + 1),
-            })?).map_err(|_|ParseError::IncorrectFormat)?, },
-        )
-    }
+    let i = 0..count_args;
+    let inner2 =
+        quote! { 
+                #(#types::from_str(splited.next().ok_or(ParseError::TooFewArguments {
+                    expected: #count_args,
+                    found: #i,
+                    message: format!("Expected but not found arg number {}", #i + 1),
+                })?).map_err(|e|ParseError::IncorrectFormat({ let e: Box<dyn std::error::Error> = e.into(); e }))?,)*
+            };
     let res = quote! {
         (|s: String| {
             #inner