Improve diagnostics

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);
 }

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();
             }

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),
 }
 

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",

tests/typ/code/call.typ

@@ -79,17 +79,17 @@
 // Error: 8 expected comma
 #func(1 2)
 
-// Error: 7-8 expected identifier
+// Error: 7-8 expected identifier, found integer
 // Error: 9 expected expression
 #func(1:)
 
-// Error: 7-8 expected identifier
+// Error: 7-8 expected identifier, found integer
 #func(1:2)
 
-// Error: 7-12 expected identifier
-#func("abc":2)
+// Error: 7-12 expected identifier, found string
+#func("abc": 2)
 
-// Error: 7-10 expected identifier
+// Error: 7-10 expected identifier, found group
 {func((x):1)}
 
 ---

tests/typ/code/closure.typ

@@ -145,13 +145,13 @@
 }
 
 ---
-// Error: 6-16 expected identifier, named pair or argument sink
+// Error: 6-16 expected identifier, named pair or argument sink, found keyed pair
 {(a, "named": b) => none}
 
 ---
-// Error: 10-15 expected identifier
+// Error: 10-15 expected identifier, found string
 #let foo("key": b) = key
 
 ---
-// Error: 10-14 expected identifier
+// Error: 10-14 expected identifier, found `none`
 #let foo(none: b) = key

tests/typ/code/dict.typ

@@ -49,12 +49,12 @@
 
 ---
 // Simple expression after already being identified as a dictionary.
-// Error: 9-10 expected named or keyed pair, found expression
+// Error: 9-10 expected named or keyed pair, found identifier
 {(a: 1, b)}
 
 // Identified as dictionary due to initial colon.
-// Error: 4-5 expected named or keyed pair, found expression
+// Error: 4-5 expected named or keyed pair, found integer
 // Error: 5 expected comma
-// Error: 12-16 expected identifier or string
+// Error: 12-16 expected identifier or string, found boolean
 // Error: 17-18 expected expression, found colon
 {(:1 b:"", true::)}

tests/typ/code/import.typ

@@ -71,11 +71,11 @@ This is never reached.
 // Error: 8 expected keyword `from`
 #import
 
-// Error: 9-19 expected identifier
+// Error: 9-19 expected identifier, found string
 // Error: 19 expected keyword `from`
 #import "file.typ"
 
-// Error: 16-19 expected identifier
+// Error: 16-19 expected identifier, found string
 // Error: 22 expected keyword `from`
 #import afrom, "b", c
 
@@ -108,7 +108,6 @@ This is never reached.
 
 // A star in the list.
 // Error: 12-13 expected expression, found star
-// Error: 13-14 expected expression, found comma
 #import a, *, b from "target.typ"
 
 // An item after a star.
@@ -117,5 +116,5 @@ This is never reached.
 #import *, a from "target.typ"
 
 ---
-// Error: 9-13 expected identifier
+// Error: 9-13 expected identifier, found named pair
 #import a: 1 from ""

tests/typ/code/spread.typ

@@ -62,7 +62,7 @@
 #min(.."nope")
 
 ---
-// Error: 8-14 expected identifier, named pair or argument sink
+// Error: 8-14 expected identifier, named pair or argument sink, found spread
 #let f(..true) = none
 
 ---