From 2f5a9fcc7dccdaa8fdc10fe59ceee73f2c3f294f Mon Sep 17 00:00:00 2001
From: Armani Ferrante <armaniferrante@gmail.com>
Date: Sun, 30 May 2021 13:31:28 -0700
Subject: [PATCH] lang: Change context error span and add constraint docs
 (#342)

---
 lang/derive/accounts/src/lib.rs    | 3 ++-
 lang/syn/src/parser/program/mod.rs | 7 +------
 2 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/lang/derive/accounts/src/lib.rs b/lang/derive/accounts/src/lib.rs
index f7d0b67d..f6f05a56 100644
--- a/lang/derive/accounts/src/lib.rs
+++ b/lang/derive/accounts/src/lib.rs
@@ -43,7 +43,8 @@ use syn::parse_macro_input;
 /// | `#[account(belongs_to = <target>)]` | On `ProgramAccount` or `CpiAccount` structs | Checks the `target` field on the account matches the `target` field in the struct deriving `Accounts`. |
 /// | `#[account(has_one = <target>)]` | On `ProgramAccount` or `CpiAccount` structs | Semantically different, but otherwise the same as `belongs_to`. |
 /// | `#[account(seeds = [<seeds>])]` | On `AccountInfo` structs | Seeds for the program derived address an `AccountInfo` struct represents. |
-/// | `#[account("<literal>")]` | On any type deriving `Accounts` | Executes the given code literal as a constraint. The literal should evaluate to a boolean. |
+/// | `#[account(constraint = <expression>)]` | On any type deriving `Accounts` | Executes the given code as a constraint. The expression should evaluate to a boolean. |
+/// | `#[account("<literal>")]` | Deprecated | Executes the given code literal as a constraint. The literal should evaluate to a boolean. |
 /// | `#[account(rent_exempt = <skip>)]` | On `AccountInfo` or `ProgramAccount` structs | Optional attribute to skip the rent exemption check. By default, all accounts marked with `#[account(init)]` will be rent exempt, and so this should rarely (if ever) be used. Similarly, omitting `= skip` will mark the account rent exempt. |
 /// | `#[account(executable)]` | On `AccountInfo` structs | Checks the given account is an executable program. |
 /// | `#[account(state = <target>)]` | On `CpiState` structs | Checks the given state is the canonical state account for the target program. |
diff --git a/lang/syn/src/parser/program/mod.rs b/lang/syn/src/parser/program/mod.rs
index 117e93d9..9ef410ad 100644
--- a/lang/syn/src/parser/program/mod.rs
+++ b/lang/syn/src/parser/program/mod.rs
@@ -29,12 +29,7 @@ fn ctx_accounts_ident(path_ty: &syn::PatType) -> ParseResult<proc_macro2::Ident>
 
     let generic_args = match &segment.arguments {
         syn::PathArguments::AngleBracketed(args) => args,
-        _ => {
-            return Err(ParseError::new(
-                segment.arguments.span(),
-                "expected generic arguments here",
-            ))
-        }
+        _ => return Err(ParseError::new(path_ty.span(), "missing accounts context")),
     };
     let generic_ty = generic_args
         .args