feat(types): add concept registry for type checking

ConceptRegistry tracks all concepts and sub_concepts, providing lookup
and validation for sub-concept variant/field references. Supports both
enum and record sub-concept kinds.

src/resolve/types.rs

@@ -3,9 +3,20 @@
 //! These types are similar to AST types but represent fully resolved,
 //! validated entities with all cross-references resolved.
 
-use crate::syntax::ast::{
-    Field,
-    Span,
+use std::collections::HashMap;
+
+use crate::{
+    resolve::{
+        ResolveError,
+        Result,
+    },
+    syntax::ast::{
+        Declaration,
+        Field,
+        File,
+        Span,
+        SubConceptKind,
+    },
 };
 
 /// A fully resolved file with all cross-references resolved
@@ -137,3 +148,350 @@ pub struct ResolvedEnum {
     pub span: Span,
     pub qualified_path: Vec<String>,
 }
+
+// ===== Concept Registry =====
+
+/// Information about a registered concept
+#[derive(Debug, Clone)]
+pub struct ConceptInfo {
+    pub name: String,
+    pub sub_concepts: HashMap<String, SubConceptInfo>,
+}
+
+/// Information about a registered sub-concept
+#[derive(Debug, Clone)]
+pub struct SubConceptInfo {
+    pub name: String,
+    pub parent: String,
+    pub kind: SubConceptKind,
+}
+
+/// Registry tracking all concepts and sub_concepts for type checking
+#[derive(Debug, Clone, Default)]
+pub struct ConceptRegistry {
+    concepts: HashMap<String, ConceptInfo>,
+}
+
+impl ConceptRegistry {
+    pub fn new() -> Self {
+        Self {
+            concepts: HashMap::new(),
+        }
+    }
+
+    /// Build a registry from a parsed file
+    pub fn from_file(file: &File) -> Self {
+        let mut registry = Self::new();
+
+        for decl in &file.declarations {
+            match decl {
+                | Declaration::Concept(c) => {
+                    registry.register_concept(c.name.clone());
+                },
+                | Declaration::SubConcept(sc) => {
+                    registry.register_sub_concept(
+                        sc.parent_concept.clone(),
+                        sc.name.clone(),
+                        sc.kind.clone(),
+                    );
+                },
+                | _ => {},
+            }
+        }
+
+        registry
+    }
+
+    /// Register a new concept
+    pub fn register_concept(&mut self, name: String) {
+        self.concepts
+            .entry(name.clone())
+            .or_insert_with(|| ConceptInfo {
+                name,
+                sub_concepts: HashMap::new(),
+            });
+    }
+
+    /// Register a sub-concept under its parent
+    pub fn register_sub_concept(&mut self, parent: String, name: String, kind: SubConceptKind) {
+        let concept = self
+            .concepts
+            .entry(parent.clone())
+            .or_insert_with(|| ConceptInfo {
+                name: parent.clone(),
+                sub_concepts: HashMap::new(),
+            });
+
+        concept
+            .sub_concepts
+            .insert(name.clone(), SubConceptInfo { name, parent, kind });
+    }
+
+    /// Look up a concept by name
+    pub fn lookup_concept(&self, name: &str) -> Option<&ConceptInfo> {
+        self.concepts.get(name)
+    }
+
+    /// Validate that a sub-concept variant reference is valid
+    ///
+    /// For enum sub-concepts, checks that the variant exists.
+    /// For record sub-concepts, checks that the field exists.
+    pub fn validate_sub_concept_reference(
+        &self,
+        parent: &str,
+        sub_concept: &str,
+        variant: &str,
+    ) -> Result<()> {
+        let concept = self
+            .concepts
+            .get(parent)
+            .ok_or_else(|| ResolveError::ValidationError {
+                message: format!("Concept '{}' not found", parent),
+                help: Some(format!(
+                    "Add 'concept {}' to define this concept before referencing it.",
+                    parent
+                )),
+            })?;
+
+        let sc = concept.sub_concepts.get(sub_concept).ok_or_else(|| {
+            let available = concept
+                .sub_concepts
+                .keys()
+                .map(|k| k.as_str())
+                .collect::<Vec<_>>()
+                .join(", ");
+            ResolveError::ValidationError {
+                message: format!("Sub-concept '{}.{}' not found", parent, sub_concept),
+                help: Some(format!(
+                    "Available sub-concepts for '{}': {}",
+                    parent,
+                    if available.is_empty() {
+                        "(none)".to_string()
+                    } else {
+                        available
+                    }
+                )),
+            }
+        })?;
+
+        match &sc.kind {
+            | SubConceptKind::Enum { variants } => {
+                if !variants.contains(&variant.to_string()) {
+                    let available = variants.join(", ");
+                    return Err(ResolveError::ValidationError {
+                        message: format!(
+                            "Variant '{}' not found in sub-concept '{}.{}'",
+                            variant, parent, sub_concept
+                        ),
+                        help: Some(format!("Available variants: {}", available)),
+                    });
+                }
+            },
+            | SubConceptKind::Record { fields } => {
+                if !fields.iter().any(|f| f.name == variant) {
+                    let available = fields
+                        .iter()
+                        .map(|f| f.name.as_str())
+                        .collect::<Vec<_>>()
+                        .join(", ");
+                    return Err(ResolveError::ValidationError {
+                        message: format!(
+                            "Field '{}' not found in record sub-concept '{}.{}'",
+                            variant, parent, sub_concept
+                        ),
+                        help: Some(format!("Available fields: {}", available)),
+                    });
+                }
+            },
+        }
+
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_register_and_lookup_concept() {
+        let mut registry = ConceptRegistry::new();
+        registry.register_concept("Cup".to_string());
+
+        let concept = registry.lookup_concept("Cup");
+        assert!(concept.is_some());
+        assert_eq!(concept.unwrap().name, "Cup");
+    }
+
+    #[test]
+    fn test_lookup_missing_concept() {
+        let registry = ConceptRegistry::new();
+        assert!(registry.lookup_concept("Cup").is_none());
+    }
+
+    #[test]
+    fn test_register_sub_concept_enum() {
+        let mut registry = ConceptRegistry::new();
+        registry.register_concept("Cup".to_string());
+        registry.register_sub_concept(
+            "Cup".to_string(),
+            "Type".to_string(),
+            SubConceptKind::Enum {
+                variants: vec![
+                    "Small".to_string(),
+                    "Medium".to_string(),
+                    "Large".to_string(),
+                ],
+            },
+        );
+
+        let concept = registry.lookup_concept("Cup").unwrap();
+        assert_eq!(concept.sub_concepts.len(), 1);
+        assert!(concept.sub_concepts.contains_key("Type"));
+    }
+
+    #[test]
+    fn test_register_sub_concept_record() {
+        let mut registry = ConceptRegistry::new();
+        registry.register_concept("Cup".to_string());
+        registry.register_sub_concept(
+            "Cup".to_string(),
+            "Material".to_string(),
+            SubConceptKind::Record {
+                fields: vec![Field {
+                    name: "weight".to_string(),
+                    value: crate::syntax::ast::Value::Number(100),
+                    span: Span::new(0, 10),
+                }],
+            },
+        );
+
+        let concept = registry.lookup_concept("Cup").unwrap();
+        assert!(concept.sub_concepts.contains_key("Material"));
+    }
+
+    #[test]
+    fn test_validate_valid_variant_reference() {
+        let mut registry = ConceptRegistry::new();
+        registry.register_concept("Cup".to_string());
+        registry.register_sub_concept(
+            "Cup".to_string(),
+            "Type".to_string(),
+            SubConceptKind::Enum {
+                variants: vec!["Small".to_string(), "Large".to_string()],
+            },
+        );
+
+        assert!(registry
+            .validate_sub_concept_reference("Cup", "Type", "Small")
+            .is_ok());
+    }
+
+    #[test]
+    fn test_validate_invalid_variant_reference() {
+        let mut registry = ConceptRegistry::new();
+        registry.register_concept("Cup".to_string());
+        registry.register_sub_concept(
+            "Cup".to_string(),
+            "Type".to_string(),
+            SubConceptKind::Enum {
+                variants: vec!["Small".to_string(), "Large".to_string()],
+            },
+        );
+
+        let result = registry.validate_sub_concept_reference("Cup", "Type", "Huge");
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn test_validate_missing_concept() {
+        let registry = ConceptRegistry::new();
+        let result = registry.validate_sub_concept_reference("Cup", "Type", "Small");
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn test_validate_missing_sub_concept() {
+        let mut registry = ConceptRegistry::new();
+        registry.register_concept("Cup".to_string());
+
+        let result = registry.validate_sub_concept_reference("Cup", "Type", "Small");
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn test_validate_record_field_reference() {
+        let mut registry = ConceptRegistry::new();
+        registry.register_concept("Cup".to_string());
+        registry.register_sub_concept(
+            "Cup".to_string(),
+            "Size".to_string(),
+            SubConceptKind::Record {
+                fields: vec![
+                    Field {
+                        name: "height".to_string(),
+                        value: crate::syntax::ast::Value::Number(10),
+                        span: Span::new(0, 10),
+                    },
+                    Field {
+                        name: "width".to_string(),
+                        value: crate::syntax::ast::Value::Number(5),
+                        span: Span::new(0, 10),
+                    },
+                ],
+            },
+        );
+
+        assert!(registry
+            .validate_sub_concept_reference("Cup", "Size", "height")
+            .is_ok());
+        assert!(registry
+            .validate_sub_concept_reference("Cup", "Size", "depth")
+            .is_err());
+    }
+
+    #[test]
+    fn test_from_file() {
+        let file = File {
+            declarations: vec![
+                Declaration::Concept(crate::syntax::ast::ConceptDecl {
+                    name: "Cup".to_string(),
+                    span: Span::new(0, 10),
+                }),
+                Declaration::SubConcept(crate::syntax::ast::SubConceptDecl {
+                    name: "Type".to_string(),
+                    parent_concept: "Cup".to_string(),
+                    kind: SubConceptKind::Enum {
+                        variants: vec!["Small".to_string(), "Large".to_string()],
+                    },
+                    span: Span::new(20, 60),
+                }),
+            ],
+        };
+
+        let registry = ConceptRegistry::from_file(&file);
+        let concept = registry.lookup_concept("Cup").unwrap();
+        assert_eq!(concept.sub_concepts.len(), 1);
+        assert!(registry
+            .validate_sub_concept_reference("Cup", "Type", "Small")
+            .is_ok());
+    }
+
+    #[test]
+    fn test_sub_concept_auto_creates_parent() {
+        let mut registry = ConceptRegistry::new();
+        // Register sub-concept without explicitly registering parent
+        registry.register_sub_concept(
+            "Cup".to_string(),
+            "Type".to_string(),
+            SubConceptKind::Enum {
+                variants: vec!["Small".to_string()],
+            },
+        );
+
+        // Parent should be auto-created
+        let concept = registry.lookup_concept("Cup");
+        assert!(concept.is_some());
+        assert_eq!(concept.unwrap().sub_concepts.len(), 1);
+    }
+}