From ad901c2cdbcb421355f5ecef5dc86c14de293c9a Mon Sep 17 00:00:00 2001
From: Heinenen <37484430+Heinenen@users.noreply.github.com>
Date: Tue, 16 Jan 2024 09:52:56 +0100
Subject: [PATCH] Syntax error if function name is parenthesized (#3058)

Co-authored-by: Laurenz <laurmaedje@gmail.com>
---
 crates/typst-syntax/src/parser.rs | 22 +++++++++-------------
 tests/typ/compiler/let.typ        |  7 +++++++
 2 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/crates/typst-syntax/src/parser.rs b/crates/typst-syntax/src/parser.rs
index 9e718b300..b77c5068f 100644
--- a/crates/typst-syntax/src/parser.rs
+++ b/crates/typst-syntax/src/parser.rs
@@ -984,8 +984,7 @@ fn args(p: &mut Parser) {
 
 enum PatternKind {
     Ident,
-    Placeholder,
-    Destructuring,
+    Other,
 }
 
 fn pattern(p: &mut Parser) -> PatternKind {
@@ -994,14 +993,12 @@ fn pattern(p: &mut Parser) -> PatternKind {
         let kind = collection(p, false);
         validate_pattern_at(p, m, true);
 
-        if kind == SyntaxKind::Parenthesized {
-            PatternKind::Ident
-        } else {
+        if kind != SyntaxKind::Parenthesized {
             p.wrap(m, SyntaxKind::Destructuring);
-            PatternKind::Destructuring
         }
+        PatternKind::Other
     } else if p.eat_if(SyntaxKind::Underscore) {
-        PatternKind::Placeholder
+        PatternKind::Other
     } else {
         p.expect(SyntaxKind::Ident);
         PatternKind::Ident
@@ -1014,22 +1011,21 @@ fn let_binding(p: &mut Parser) {
 
     let m2 = p.marker();
     let mut closure = false;
-    let mut destructuring = false;
+    let mut other = false;
     match pattern(p) {
         PatternKind::Ident => {
-            closure = p.directly_at(SyntaxKind::LeftParen);
-            if closure {
+            if p.directly_at(SyntaxKind::LeftParen) {
                 let m3 = p.marker();
                 collection(p, false);
                 validate_params_at(p, m3);
                 p.wrap(m3, SyntaxKind::Params);
+                closure = true;
             }
         }
-        PatternKind::Placeholder => {}
-        PatternKind::Destructuring => destructuring = true,
+        PatternKind::Other => other = true,
     }
 
-    let f = if closure || destructuring { Parser::expect } else { Parser::eat_if };
+    let f = if closure || other { Parser::expect } else { Parser::eat_if };
     if f(p, SyntaxKind::Eq) {
         code_expr(p);
     }
diff --git a/tests/typ/compiler/let.typ b/tests/typ/compiler/let.typ
index accd9d042..06f07394e 100644
--- a/tests/typ/compiler/let.typ
+++ b/tests/typ/compiler/let.typ
@@ -275,3 +275,10 @@ Three
 
 // Error: 15 expected expression
 #let func(x) =
+---
+// Error: 12 expected equals sign
+#let (func)(x)
+---
+// Error: 12 expected equals sign
+// Error: 15-15 expected semicolon or line break
+#let (func)(x) = 3