Multi-unit symbol position support

crates/pcb-zen-core/src/convert.rs

@@ -701,8 +701,13 @@ impl ModuleConverter {
     }
 
     fn is_instance_position(&self, key: &str, instance_ref: &InstanceRef) -> Option<()> {
+        // Strip @U suffix from the key if present (for multi-unit symbols)
+        // e.g., "U1.OPEN_Q_6490CS@U1" -> "U1.OPEN_Q_6490CS"
+        let key_without_unit = key.split('@').next().unwrap_or(key);
+
         // Traverse the instance hierarchy using the dot-separated key
-        key.split('.')
+        key_without_unit
+            .split('.')
             .try_fold(instance_ref, |current_ref, part| {
                 self.schematic
                     .instances

crates/pcb-zen-core/src/lang/validation.rs

@@ -6,8 +6,12 @@ pub enum ValidationError {
     EmptyName { context: String },
     #[error("{context} cannot contain whitespace. Got: {name:?}")]
     NameContainsWhitespace { context: String, name: String },
-    #[error("{context} cannot contain dots. Got: {name:?}")]
-    NameContainsDots { context: String, name: String },
+    #[error("{context} cannot contain invalid characters {invalid_chars:?}. Got: {name:?}")]
+    NameContainsInvalidChars {
+        context: String,
+        name: String,
+        invalid_chars: String,
+    },
     #[error("{context} must contain only ASCII characters. Got: {name:?}")]
     NameNotAscii { context: String, name: String },
 }
@@ -45,9 +49,10 @@ pub fn validate_identifier_name(name: &str, context: &str) -> Result<(), Validat
 
     // Check for dots (confusing for hierarchical references)
     if name.contains('.') {
-        return Err(ValidationError::NameContainsDots {
+        return Err(ValidationError::NameContainsInvalidChars {
             context: context.to_string(),
             name: name.to_string(),
+            invalid_chars: ".".to_string(),
         });
     }
 
@@ -59,6 +64,15 @@ pub fn validate_identifier_name(name: &str, context: &str) -> Result<(), Validat
         });
     }
 
+    // Check for @ sign
+    if name.contains('@') {
+        return Err(ValidationError::NameContainsInvalidChars {
+            context: context.to_string(),
+            name: name.to_string(),
+            invalid_chars: "@".to_string(),
+        });
+    }
+
     Ok(())
 }
 
@@ -84,7 +98,6 @@ mod tests {
             "power-rail",
             "VCC+",          // Plus signs allowed
             "GND-",          // Minus signs allowed
-            "R@1",           // @ signs allowed
             "C#1",           // # signs allowed
             "L$1",           // $ signs allowed
             "Q&1",           // & signs allowed
@@ -134,6 +147,23 @@ mod tests {
         }
     }
 
+    #[test]
+    fn test_invalid_names_with_at_sign() {
+        let invalid_names = vec!["R@1", "LED@STATUS", "power@rail"];
+        for name in invalid_names {
+            let result = validate_identifier_name(name, "Test name");
+            assert!(result.is_err(), "Expected '{}' to be invalid", name);
+            let error_msg = format!("{}", result.unwrap_err());
+            assert!(
+                error_msg.contains("cannot contain invalid characters")
+                    && error_msg.contains("\"@\""),
+                "Expected @ sign error for '{}', got: {}",
+                name,
+                error_msg
+            );
+        }
+    }
+
     #[test]
     fn test_invalid_names_with_dots() {
         let invalid_names = vec![
@@ -150,7 +180,8 @@ mod tests {
             assert!(result.is_err(), "Expected '{}' to be invalid", name);
             let error_msg = format!("{}", result.unwrap_err());
             assert!(
-                error_msg.contains("cannot contain dots"),
+                error_msg.contains("cannot contain invalid characters")
+                    && error_msg.contains("\".\""),
                 "Expected dot error for '{}', got: {}",
                 name,
                 error_msg