From 1bca9ccecb9edb583a0a94bd3611147b66909ab9 Mon Sep 17 00:00:00 2001
From: Laurenz <laurmaedje@gmail.com>
Date: Wed, 4 May 2022 23:26:15 +0200
Subject: Improve diagnostics

---
 src/parse/mod.rs    | 12 ++++++++----
 src/parse/parser.rs |  8 +++++++-
 src/syntax/ast.rs   |  2 +-
 src/syntax/mod.rs   |  4 ++--
 4 files changed, 18 insertions(+), 8 deletions(-)

(limited to 'src')

diff --git a/src/parse/mod.rs b/src/parse/mod.rs
index 8bf7b1c5..b473c9af 100644
--- a/src/parse/mod.rs
+++ b/src/parse/mod.rs
@@ -604,6 +604,7 @@ fn collection(p: &mut Parser, keyed: bool) -> (CollectionKind, usize) {
                 missing_coma = Some(p.trivia_start());
             }
         } else {
+            p.eat_if(NodeKind::Comma);
             kind = Some(CollectionKind::Group);
         }
     }
@@ -638,11 +639,15 @@ fn item(p: &mut Parser, keyed: bool) -> ParseResult<NodeKind> {
                 p.eat();
                 marker.perform(p, NodeKind::Keyed, expr)?;
             }
-            _ => {
+            kind => {
                 let mut msg = EcoString::from("expected identifier");
                 if keyed {
                     msg.push_str(" or string");
                 }
+                if let Some(kind) = kind {
+                    msg.push_str(", found ");
+                    msg.push_str(kind.as_str());
+                }
                 let error = NodeKind::Error(ErrorPos::Full, msg);
                 marker.end(p, error);
                 p.eat();
@@ -661,8 +666,7 @@ fn item(p: &mut Parser, keyed: bool) -> ParseResult<NodeKind> {
 /// expressions.
 fn array(p: &mut Parser, marker: Marker) {
     marker.filter_children(p, |x| match x.kind() {
-        NodeKind::Named => Err("expected expression, found named pair"),
-        NodeKind::Keyed => Err("expected expression, found keyed pair"),
+        NodeKind::Named | NodeKind::Keyed => Err("expected expression"),
         _ => Ok(()),
     });
     marker.end(p, NodeKind::ArrayExpr);
@@ -685,7 +689,7 @@ fn dict(p: &mut Parser, marker: Marker) {
             Ok(())
         }
         NodeKind::Spread | NodeKind::Comma | NodeKind::Colon => Ok(()),
-        _ => Err("expected named or keyed pair, found expression"),
+        _ => Err("expected named or keyed pair"),
     });
     marker.end(p, NodeKind::DictExpr);
 }
diff --git a/src/parse/parser.rs b/src/parse/parser.rs
index 50bb5711..f3a3ffd1 100644
--- a/src/parse/parser.rs
+++ b/src/parse/parser.rs
@@ -4,6 +4,7 @@ use std::ops::Range;
 
 use super::{TokenMode, Tokens};
 use crate::syntax::{ErrorPos, Green, GreenData, GreenNode, NodeKind};
+use crate::util::EcoString;
 
 /// A convenient token-based parser.
 pub struct Parser<'s> {
@@ -474,7 +475,12 @@ impl Marker {
             }
 
             if let Err(msg) = f(child) {
-                let error = NodeKind::Error(ErrorPos::Full, msg.into());
+                let mut msg = EcoString::from(msg);
+                if msg.starts_with("expected") {
+                    msg.push_str(", found ");
+                    msg.push_str(child.kind().as_str());
+                }
+                let error = NodeKind::Error(ErrorPos::Full, msg);
                 let inner = mem::take(child);
                 *child = GreenNode::with_child(error, inner).into();
             }
diff --git a/src/syntax/ast.rs b/src/syntax/ast.rs
index 1add2fd6..95421213 100644
--- a/src/syntax/ast.rs
+++ b/src/syntax/ast.rs
@@ -964,7 +964,7 @@ pub enum ClosureParam {
     Pos(Ident),
     /// A named parameter with a default value: `draw: false`.
     Named(Named),
-    /// A parameter sink: `..args`.
+    /// An argument sink: `..args`.
     Sink(Ident),
 }
 
diff --git a/src/syntax/mod.rs b/src/syntax/mod.rs
index 09d7265d..abe541b8 100644
--- a/src/syntax/mod.rs
+++ b/src/syntax/mod.rs
@@ -662,7 +662,7 @@ pub enum NodeKind {
     MethodCall,
     /// A function call's argument list: `(x, y)`.
     CallArgs,
-    /// Spreaded arguments or a parameter sink: `..x`.
+    /// Spreaded arguments or a argument sink: `..x`.
     Spread,
     /// A closure expression: `(x, y) => z`.
     ClosureExpr,
@@ -906,7 +906,7 @@ impl NodeKind {
             Self::FuncCall => "function call",
             Self::MethodCall => "method call",
             Self::CallArgs => "call arguments",
-            Self::Spread => "parameter sink",
+            Self::Spread => "spread",
             Self::ClosureExpr => "closure",
             Self::ClosureParams => "closure parameters",
             Self::LetExpr => "`let` expression",
-- 
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