From fc47008d0c01fd1658626f6ed7fa4a7a695da3be Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Capucho?= <jcapucho7@gmail.com>
Date: Thu, 19 Aug 2021 20:56:44 +0100
Subject: [PATCH] [glsl-in] Allow expression statements to begin with ++ or --

This would otherwise cause the parser to enter an infinite loop.

Fixes #1232
---
 src/front/glsl/parser/functions.rs |  2 ++
 src/front/glsl/parser_tests.rs     | 19 ++++++++++++++++++-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/src/front/glsl/parser/functions.rs b/src/front/glsl/parser/functions.rs
index af1568fcd4..c91e6aeb22 100644
--- a/src/front/glsl/parser/functions.rs
+++ b/src/front/glsl/parser/functions.rs
@@ -495,6 +495,8 @@ impl<'source> ParsingContext<'source> {
             | TokenValue::Bang
             | TokenValue::Tilde
             | TokenValue::LeftParen
+            | TokenValue::Increment
+            | TokenValue::Decrement
             | TokenValue::Identifier(_)
             | TokenValue::TypeName(_)
             | TokenValue::IntConstant(_)
diff --git a/src/front/glsl/parser_tests.rs b/src/front/glsl/parser_tests.rs
index 10c4b92c20..717737bc59 100644
--- a/src/front/glsl/parser_tests.rs
+++ b/src/front/glsl/parser_tests.rs
@@ -778,9 +778,10 @@ fn swizzles() {
 }
 
 #[test]
-fn vector_indexing() {
+fn expressions() {
     let mut parser = Parser::default();
 
+    // Vector indexing
     parser
         .parse(
             &Options::from(ShaderStage::Vertex),
@@ -795,4 +796,20 @@ fn vector_indexing() {
         "#,
         )
         .unwrap();
+
+    // Prefix increment/decrement
+    parser
+        .parse(
+            &Options::from(ShaderStage::Vertex),
+            r#"
+        #  version 450
+        void main() {
+            uint index = 0;
+            
+            --index;
+            ++index;
+        }
+        "#,
+        )
+        .unwrap();
 }