diff --git a/CHANGELOG.md b/CHANGELOG.md
index c0b20648..8c60ac64 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,11 @@ Rhai Release Notes
 Version 1.3.1
 =============
 
+Bug fixes
+---------
+
+* Custom syntax now works properly inside binary expressions.
+
 Enhancements
 ------------
 
diff --git a/README.md b/README.md
index 07a221a4..bfda54e5 100644
--- a/README.md
+++ b/README.md
@@ -79,7 +79,7 @@ The [`scripts`](https://github.com/rhaiscript/rhai/tree/master/scripts) subdirec
 
 Below is the standard _Fibonacci_ example for scripting languages:
 
-```js
+```ts
 // This Rhai script calculates the n-th Fibonacci number using a
 // really dumb algorithm to test the speed of the scripting engine.
 
diff --git a/src/parser.rs b/src/parser.rs
index 25bc5272..600f0090 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -1550,9 +1550,26 @@ fn parse_unary(
     settings.ensure_level_within_max_limit(state.max_expr_depth)?;
 
     let (token, token_pos) = input.peek().expect(NEVER_ENDS);
+    let token_pos = *token_pos;
 
     let mut settings = settings;
-    settings.pos = *token_pos;
+    settings.pos = token_pos;
+
+    // Check if it is a custom syntax.
+    if !state.engine.custom_syntax.is_empty() {
+        match token {
+            Token::Custom(key) | Token::Reserved(key) | Token::Identifier(key) => {
+                if let Some((key, syntax)) = state.engine.custom_syntax.get_key_value(key.as_ref())
+                {
+                    input.next().expect(NEVER_ENDS);
+                    return parse_custom_syntax(
+                        input, state, lib, settings, key, syntax, token_pos,
+                    );
+                }
+            }
+            _ => (),
+        }
+    }
 
     match token {
         // -expr
@@ -2251,25 +2268,6 @@ fn parse_expr(
     let mut settings = settings;
     settings.pos = input.peek().expect(NEVER_ENDS).1;
 
-    // Check if it is a custom syntax.
-    if !state.engine.custom_syntax.is_empty() {
-        let (token, pos) = input.peek().expect(NEVER_ENDS);
-        let token_pos = *pos;
-
-        match token {
-            Token::Custom(key) | Token::Reserved(key) | Token::Identifier(key) => {
-                if let Some((key, syntax)) = state.engine.custom_syntax.get_key_value(key.as_ref())
-                {
-                    input.next().expect(NEVER_ENDS);
-                    return parse_custom_syntax(
-                        input, state, lib, settings, key, syntax, token_pos,
-                    );
-                }
-            }
-            _ => (),
-        }
-    }
-
     // Parse expression normally.
     let lhs = parse_unary(input, state, lib, settings.level_up())?;
     parse_binary_op(
diff --git a/src/tokenizer.rs b/src/tokenizer.rs
index c039a8dc..e5a4905d 100644
--- a/src/tokenizer.rs
+++ b/src/tokenizer.rs
@@ -863,11 +863,6 @@ impl Token {
         use Token::*;
 
         Precedence::new(match self {
-            // Assignments are not considered expressions - set to zero
-            Equals | PlusAssign | MinusAssign | MultiplyAssign | DivideAssign | PowerOfAssign
-            | LeftShiftAssign | RightShiftAssign | AndAssign | OrAssign | XOrAssign
-            | ModuloAssign => 0,
-
             Or | XOr | Pipe => 30,
 
             And | Ampersand => 60,
@@ -886,8 +881,6 @@ impl Token {
 
             LeftShift | RightShift => 210,
 
-            Period => 240,
-
             _ => 0,
         })
     }
@@ -898,14 +891,6 @@ impl Token {
         use Token::*;
 
         match self {
-            // Assignments bind to the right
-            Equals | PlusAssign | MinusAssign | MultiplyAssign | DivideAssign | PowerOfAssign
-            | LeftShiftAssign | RightShiftAssign | AndAssign | OrAssign | XOrAssign
-            | ModuloAssign => true,
-
-            // Property access binds to the right
-            Period => true,
-
             // Exponentiation binds to the right
             PowerOf => true,
 
@@ -1662,6 +1647,17 @@ fn get_next_token_inner(
             // Shebang
             ('#', '!') => return Some((Token::Reserved("#!".into()), start_pos)),
 
+            ('#', ' ') => {
+                eat_next(stream, pos);
+                let token = if stream.peek_next() == Some('{') {
+                    eat_next(stream, pos);
+                    "# {"
+                } else {
+                    "#"
+                };
+                return Some((Token::Reserved(token.into()), start_pos));
+            }
+
             ('#', _) => return Some((Token::Reserved("#".into()), start_pos)),
 
             // Operators
@@ -2182,7 +2178,7 @@ impl<'a> Iterator for TokenIterator<'a> {
                 ("(*", false) | ("*)", false) => Token::LexError(LERR::ImproperSymbol(s.to_string(),
                     "'(* .. *)' is not a valid comment format. This is not Pascal! Should it be '/* .. */'?".to_string(),
                 )),
-                ("#", false) => Token::LexError(LERR::ImproperSymbol(s.to_string(),
+                ("# {", false) => Token::LexError(LERR::ImproperSymbol(s.to_string(),
                     "'#' is not a valid symbol. Should it be '#{'?".to_string(),
                 )),
                 // Reserved keyword/operator that is custom.
diff --git a/tests/custom_syntax.rs b/tests/custom_syntax.rs
index f381bdf0..cbc9962a 100644
--- a/tests/custom_syntax.rs
+++ b/tests/custom_syntax.rs
@@ -239,3 +239,37 @@ fn test_custom_syntax_raw() -> Result<(), Box<EvalAltResult>> {
 
     Ok(())
 }
+
+#[test]
+fn test_custom_syntax_raw2() -> Result<(), Box<EvalAltResult>> {
+    let mut engine = Engine::new();
+
+    engine
+        .register_custom_operator("#", 255)?
+        .register_custom_syntax_raw(
+            "#",
+            |symbols, lookahead| match symbols.len() {
+                1 if lookahead == "-" => Ok(Some("$symbol$".into())),
+                1 => Ok(Some("$int$".into())),
+                2 if symbols[1] == "-" => Ok(Some("$int$".into())),
+                2 => Ok(None),
+                3 => Ok(None),
+                _ => unreachable!(),
+            },
+            false,
+            move |_, inputs| {
+                let id = if inputs.len() == 2 {
+                    -inputs[1].get_literal_value::<INT>().unwrap()
+                } else {
+                    inputs[0].get_literal_value::<INT>().unwrap()
+                };
+                Ok(id.into())
+            },
+        );
+
+    assert_eq!(engine.eval::<INT>("let x = 41; x + #1")?, 42);
+    assert_eq!(engine.eval::<INT>("#42/2")?, 21);
+    assert_eq!(engine.eval::<INT>("#-1")?, -1);
+
+    Ok(())
+}
diff --git a/tests/serde.rs b/tests/serde.rs
index 25929ac5..b1b76e3a 100644
--- a/tests/serde.rs
+++ b/tests/serde.rs
@@ -12,6 +12,7 @@ use rhai::Array;
 use rhai::Map;
 #[cfg(not(feature = "no_float"))]
 use rhai::FLOAT;
+#[cfg(not(feature = "no_float"))]
 #[cfg(feature = "decimal")]
 use rust_decimal::Decimal;