WIP more name analysis.

ast-generator/src/deserialize/struct_spec.rs

@@ -10,15 +10,14 @@ fn deserialize_field(field_yaml: &Yaml) -> StructField {
     let kind = props["kind"].as_str().unwrap();
     let wrap = if let Some(wrap) = props["wrap"].as_str() {
         match wrap {
-            "rc_ref_cell" => {
-                Some(StructFieldWrap::RcRefCell)
-            }
-            _ => panic!()
+            "rc_ref_cell" => Some(StructFieldWrap::RcRefCell),
+            _ => panic!(),
         }
     } else {
         None
     };
-    StructField::new(&name, kind, wrap)
+    let vec = get_as_bool(&props["vec"]);
+    StructField::new(&name, kind, wrap, vec)
 }
 
 fn deserialize_skip_child(props: &Yaml) -> StructChild {
@@ -112,7 +111,11 @@ fn deserialize_special_child(name: &str, props: &Yaml) -> StructChild {
     match props["kind"].as_str().unwrap() {
         "file_id" => StructChild::Special(SpecialChild::new(name, SpecialChildKind::FileId)),
         "range" => StructChild::Special(SpecialChild::new(name, SpecialChildKind::Range)),
-        _ => panic!("Invalid special child kind {} in {}", props["kind"].as_str().unwrap(), name),
+        _ => panic!(
+            "Invalid special child kind {} in {}",
+            props["kind"].as_str().unwrap(),
+            name
+        ),
     }
 }
 
@@ -169,7 +172,8 @@ pub fn deserialize_struct_spec(name: &str, struct_yaml: &Yaml) -> StructSpec {
     };
 
     let fields = if struct_yaml["fields"].is_array() {
-        struct_yaml["fields"].as_vec()
+        struct_yaml["fields"]
+            .as_vec()
             .unwrap()
             .iter()
             .map(|field| deserialize_field(field))
@@ -180,7 +184,8 @@ pub fn deserialize_struct_spec(name: &str, struct_yaml: &Yaml) -> StructSpec {
     };
 
     let derive = if struct_yaml["derive"].is_array() {
-        struct_yaml["derive"].as_vec()
+        struct_yaml["derive"]
+            .as_vec()
             .unwrap()
             .iter()
             .map(|derive| derive.as_str().unwrap().to_string())

ast-generator/src/spec/struct_spec.rs

@@ -6,7 +6,12 @@ pub struct StructSpec {
 }
 
 impl StructSpec {
-    pub fn new(build: &str, children: Vec<Box<StructChild>>, fields: Vec<Box<StructField>>, derive: Vec<String>) -> Self {
+    pub fn new(
+        build: &str,
+        children: Vec<Box<StructChild>>,
+        fields: Vec<Box<StructField>>,
+        derive: Vec<String>,
+    ) -> Self {
         Self {
             build: build.to_string(),
             children,
@@ -51,10 +56,8 @@ impl StructChild {
 
     pub fn unwrap_special(&self) -> Option<&SpecialChild> {
         match self {
-            StructChild::Special(special_child) => {
-                Some(special_child)
-            },
-            _ => None
+            StructChild::Special(special_child) => Some(special_child),
+            _ => None,
         }
     }
 }
@@ -254,7 +257,7 @@ impl SpecialChild {
     pub fn new(name: &str, kind: SpecialChildKind) -> Self {
         Self {
             name: name.to_string(),
-            kind
+            kind,
         }
     }
 
@@ -278,14 +281,16 @@ pub struct StructField {
     name: String,
     kind: String,
     wrap: Option<StructFieldWrap>,
+    vec: bool,
 }
 
 impl StructField {
-    pub fn new(name: &str, kind: &str, wrap: Option<StructFieldWrap>) -> Self {
+    pub fn new(name: &str, kind: &str, wrap: Option<StructFieldWrap>, vec: bool) -> Self {
         Self {
             name: name.to_string(),
             kind: kind.to_string(),
             wrap,
+            vec,
         }
     }
 
@@ -300,9 +305,13 @@ impl StructField {
     pub fn wrap(&self) -> Option<&StructFieldWrap> {
         self.wrap.as_ref()
     }
+
+    pub fn vec(&self) -> bool {
+        self.vec
+    }
 }
 
 #[derive(Debug)]
 pub enum StructFieldWrap {
-    RcRefCell
+    RcRefCell,
 }

ast-generator/src/type_gen/struct_type.rs

@@ -19,9 +19,20 @@ fn make_field_accessors(field: &StructField) -> TokenStream {
             quote! { #inner }
         }
     };
-    let set_field_ident = format_ident!("set_{}", field.name());
     let field_ident_mut = format_ident!("{}_mut", field.name());
 
+    if field.vec() {
+        quote! {
+            pub fn #field_ident(&self) -> &[#field_type] {
+                self.#field_ident.as_slice()
+            }
+
+            pub fn #field_ident_mut(&mut self) -> &mut Vec<#field_type> {
+                &mut self.#field_ident
+            }
+        }
+    } else {
+        let set_field_ident = format_ident!("set_{}", field.name());
         quote! {
             pub fn #field_ident(&self) -> Option<&#field_type> {
                 self.#field_ident.as_ref()
@@ -35,19 +46,24 @@ fn make_field_accessors(field: &StructField) -> TokenStream {
                 self.#field_ident = Some(#field_ident);
             }
         }
+    }
 }
 
 fn make_field_initializer(field: &StructField) -> TokenStream {
     let field_ident = format_ident!("{}", field.name());
+    if field.vec() {
+        quote! { #field_ident: vec![] }
+    } else {
         quote! { #field_ident: None }
+    }
 }
 
 fn make_annotated_field(field: &StructField) -> TokenStream {
     let field_ident = format_ident!("{}", field.name());
     let field_type = if let Some(wrap) = field.wrap() {
+        let inner = format_ident!("{}", field.kind());
         match wrap {
             StructFieldWrap::RcRefCell => {
-                let inner = format_ident!("{}", field.kind());
                 quote! { Rc<RefCell<#inner>> }
             }
         }
@@ -56,9 +72,15 @@ fn make_annotated_field(field: &StructField) -> TokenStream {
         quote! { #inner }
     };
 
+    if field.vec() {
+        quote! {
+            #field_ident: Vec<#field_type>
+        }
+    } else {
         quote! {
             #field_ident: Option<#field_type>
         }
+    }
 }
 
 fn make_vec_child_accessors(vec_child: &VecChild) -> TokenStream {

src/bin/dmc/name_analysis.rs

@@ -8,6 +8,7 @@ use deimos::parser::{DeimosParser, Rule};
 use deimos::std_core::add_std_core_symbols;
 use pest::Parser;
 use std::path::PathBuf;
+use deimos::name_analysis::symbol_tree::SymbolTree;
 
 pub fn name_analysis(paths: &Vec<PathBuf>) -> Result<(), Box<dyn std::error::Error>> {
     let mut compilation_units = vec![];
@@ -29,9 +30,10 @@ pub fn name_analysis(paths: &Vec<PathBuf>) -> Result<(), Box<dyn std::error::Err
     }
 
     let mut symbol_table = SymbolTable::new();
+    let mut symbol_tree = SymbolTree::new();
     add_std_core_symbols(&mut symbol_table).expect("Failed to add std::core symbols.");
 
-    let diagnostics = analyze_names(&mut compilation_units, &files, &mut symbol_table);
+    let diagnostics = analyze_names(&mut compilation_units, &files, &mut symbol_table, &mut symbol_tree);
     if diagnostics.is_empty() {
         println!("Name analysis complete.");
         println!("{}", symbol_table);

src/name_analysis/first_pass.rs

@@ -1,51 +1,19 @@
-use std::cell::RefCell;
 use crate::ast::node::{CompilationUnit, Identifier, UseStatement, UseStatementSuffix};
 use crate::diagnostic::DmDiagnostic;
 use crate::name_analysis::fqn_context::FqnContext;
 use crate::name_analysis::symbol::source_definition::SourceDefinition;
 use crate::name_analysis::symbol::use_symbol::{ConcreteUseSymbol, StarUseSymbol, UseSymbol};
-use crate::name_analysis::symbol_table::{SymbolInsertError, SymbolTable};
-use crate::name_analysis::util::use_statement_base_fqn;
-use codespan_reporting::diagnostic::{Diagnostic, Label};
-use std::range::Range;
+use crate::name_analysis::symbol_table::SymbolTable;
+use crate::name_analysis::symbol_tree::SymbolTree;
+use crate::name_analysis::util;
+use crate::name_analysis::util::{handle_insert_error, use_statement_base_fqn};
+use std::cell::RefCell;
 use std::rc::Rc;
 
-fn handle_insert_error(
-    err: SymbolInsertError,
-    error_symbol_name: &str,
-    error_file_id: usize,
-    error_range: Range<usize>,
-    symbol_types: &str,
-    diagnostics: &mut Vec<DmDiagnostic>,
-) {
-    match err {
-        SymbolInsertError::SymbolAlreadyDefined(s) => {
-            let mut diagnostic = Diagnostic::error()
-                .with_message(format!(
-                    "{} symbol '{}' already defined in the current scope.",
-                    symbol_types, error_symbol_name,
-                ))
-                .with_label(
-                    Label::primary(error_file_id, error_range)
-                        .with_message("Symbol duplicated here."),
-                );
-
-            if let Some(source_definition) = s.definition() {
-                diagnostic = diagnostic.with_label(
-                    Label::secondary(source_definition.file_id(), source_definition.range())
-                        .with_message("Symbol defined here."),
-                );
-            }
-
-            diagnostics.push(diagnostic);
-        }
-    }
-}
-
 macro_rules! insert_symbol {
     ($insert_method:ident, $symbol:expr, $symbol_table:ident, $name:expr, $node:ident, $symbol_kinds:literal, $diagnostics:ident) => {
         if let Err(insert_error) = $symbol_table.$insert_method($symbol) {
-            handle_insert_error(
+            util::handle_insert_error(
                 insert_error,
                 $name,
                 $node.file_id(),
@@ -57,24 +25,11 @@ macro_rules! insert_symbol {
     };
 }
 
-macro_rules! insert_concrete_use_symbol {
-    ($symbol:expr, $symbol_table:ident, $symbol_name:expr, $source_node:ident, $symbol_kinds:literal, $diagnostics:ident) => {
-        insert_symbol!(
-            insert_concrete_use_symbol,
-            $symbol,
-            $symbol_table,
-            $symbol_name,
-            $source_node,
-            $symbol_kinds,
-            $diagnostics
-        )
-    };
-}
-
 pub fn nap1_compilation_unit(
     file_name: &str,
     compilation_unit: &mut CompilationUnit,
     symbol_table: &mut SymbolTable,
+    symbol_tree: &mut SymbolTree,
     diagnostics: &mut Vec<DmDiagnostic>,
 ) {
     let mut fqn_context = FqnContext::new();
@@ -93,22 +48,20 @@ pub fn nap1_compilation_unit(
     symbol_table.pop_scope();
 }
 
-fn handle_concrete_use_statement(
-    use_statement: &mut UseStatement,
+fn maybe_insert_concrete_use_symbol(
+    use_statement: &UseStatement,
     identifier: &Identifier,
     symbol_table: &mut SymbolTable,
     diagnostics: &mut Vec<DmDiagnostic>,
-) {
+) -> Option<Rc<RefCell<ConcreteUseSymbol>>> {
     let base_fqn = use_statement_base_fqn(use_statement);
     let to_insert = ConcreteUseSymbol::new(
         &base_fqn,
         identifier.name(),
-        Some(SourceDefinition::from_identifier(identifier))
+        Some(SourceDefinition::from_identifier(identifier)),
     );
     match symbol_table.insert_concrete_use_symbol(to_insert) {
-        Ok(inserted) => {
-            use_statement.set_use_symbol(Rc::new(RefCell::new(UseSymbol::Concrete(inserted))));
-        }
+        Ok(inserted) => Some(inserted),
         Err(insert_error) => {
             handle_insert_error(
                 insert_error,
@@ -116,8 +69,9 @@ fn handle_concrete_use_statement(
                 identifier.file_id(),
                 identifier.range(),
                 "Use Symbol",
-                diagnostics
+                diagnostics,
             );
+            None
         }
     }
 }
@@ -131,47 +85,51 @@ fn nap1_use_statement(
 
     match use_statement.suffix() {
         UseStatementSuffix::Identifier(identifier) => {
-            insert_concrete_use_symbol!(
-                ConcreteUseSymbol::new(
-                    &base_fqn,
-                    identifier.name(),
-                    Some(SourceDefinition::from_identifier(identifier))
-                ),
+            let maybe_symbol = maybe_insert_concrete_use_symbol(
+                use_statement,
+                &identifier,
                 symbol_table,
-                &base_fqn,
-                identifier,
-                "Use Statement",
-                diagnostics
-            )
+                diagnostics,
+            );
+            if let Some(concrete_use_symbol) = maybe_symbol {
+                use_statement.use_symbols_mut().push(UseSymbol::Concrete(concrete_use_symbol));
+            }
         }
         UseStatementSuffix::Star => {
-            insert_symbol!(
-                insert_star_use_symbol,
-                StarUseSymbol::new(
+            let maybe_symbol = match symbol_table.insert_star_use_symbol(
+                StarUseSymbol::new(&base_fqn, Some(SourceDefinition::from_use_statement(use_statement)))
+            ) {
+                Ok(inserted) => {
+                    Some(todo!())
+                },
+                Err(insert_error) => {
+                    handle_insert_error(
+                        insert_error,
                         &base_fqn,
-                    Some(SourceDefinition::from_use_statement(use_statement))
-                ),
-                symbol_table,
-                &base_fqn,
-                use_statement,
-                "Use Statement",
-                diagnostics
+                        use_statement.file_id(),
+                        use_statement.range(),
+                        "Star Use Symbol",
+                        diagnostics,
                     );
+                    None
+                }
+            };
         }
         UseStatementSuffix::UseList(use_list) => {
-            for identifier in use_list.identifiers() {
-                insert_concrete_use_symbol!(
-                    ConcreteUseSymbol::new(
-                        &base_fqn,
-                        identifier.name(),
-                        Some(SourceDefinition::from_identifier(identifier))
-                    ),
-                    symbol_table,
-                    &base_fqn,
+            let maybe_symbols = use_list.identifiers()
+                .map(|identifier| {
+                    maybe_insert_concrete_use_symbol(
+                        use_statement,
                         identifier,
-                    "Use Statement",
-                    diagnostics
-                );
+                        symbol_table,
+                        diagnostics,
+                    )
+                })
+                .collect::<Vec<_>>();
+            for maybe_symbol in maybe_symbols {
+                if let Some(symbol) = maybe_symbol {
+                    use_statement.use_symbols_mut().push(UseSymbol::Concrete(symbol));
+                }
             }
         }
     }

src/name_analysis/mod.rs

@@ -28,6 +28,7 @@ use crate::name_analysis::second_pass::nap2_compilation_unit;
 use crate::name_analysis::symbol_table::SymbolTable;
 use codespan_reporting::files::Files;
 use std::hash::Hash;
+use crate::name_analysis::symbol_tree::SymbolTree;
 
 pub(self) mod fqn_context;
 // mod resolve;
@@ -36,24 +37,26 @@ mod scope_table;
 mod second_pass;
 pub mod symbol;
 pub mod symbol_table;
+pub mod symbol_tree;
 mod util;
 
 pub fn analyze_names<'a, F: Files<'a, FileId = usize, Name = String>>(
     compilation_units: &mut Vec<Box<CompilationUnit>>,
     files: &'a F,
     symbol_table: &mut SymbolTable,
+    symbol_tree: &mut SymbolTree,
 ) -> Vec<DmDiagnostic> {
     let mut diagnostics = vec![];
 
     // gather symbols
     for compilation_unit in compilation_units.iter_mut() {
         let file_name = files.name(compilation_unit.file_id()).unwrap();
-        nap1_compilation_unit(&file_name, compilation_unit, symbol_table, &mut diagnostics);
+        nap1_compilation_unit(&file_name, compilation_unit, symbol_table, symbol_tree, &mut diagnostics);
     }
 
     // resolve symbols
     for compilation_unit in compilation_units {
-        nap2_compilation_unit(compilation_unit, symbol_table, &mut diagnostics);
+        nap2_compilation_unit(compilation_unit, symbol_table, symbol_tree, &mut diagnostics);
     }
 
     diagnostics.into()

src/name_analysis/second_pass.rs

@@ -1,97 +1,124 @@
 use crate::ast::node::{CompilationUnit, Identifier, UseStatement, UseStatementSuffix};
 use crate::diagnostic::DmDiagnostic;
-use crate::name_analysis::symbol::use_symbol::UseSymbol;
+use crate::name_analysis::symbol::usable_symbol::UsableSymbol;
+use crate::name_analysis::symbol::use_symbol::{ConcreteUseSymbol, UseSymbol};
 use crate::name_analysis::symbol_table::{SymbolLookupError, SymbolTable};
-use crate::name_analysis::util::use_statement_base_fqn;
-use codespan_reporting::diagnostic::{Diagnostic, Label};
-use std::range::Range;
-
-fn handle_lookup_error(
-    err: SymbolLookupError,
-    error_symbol_name: &str,
-    error_file_id: usize,
-    error_range: Range<usize>,
-    symbol_types: &str,
-    diagnostics: &mut Vec<DmDiagnostic>,
-) {
-    match err {
-        SymbolLookupError::NoDefinition => {
-            let diagnostic = Diagnostic::error()
-                .with_message(format!(
-                    "No such {} symbol '{}' in scope.",
-                    symbol_types, error_symbol_name,
-                ))
-                .with_label(
-                    Label::primary(error_file_id, error_range).with_message("Symbol used here."),
-                );
-            diagnostics.push(diagnostic);
-        }
-    }
-}
+use crate::name_analysis::symbol_tree::SymbolTree;
+use crate::name_analysis::util::{handle_lookup_error, use_statement_base_fqn};
+use std::cell::RefCell;
+use std::rc::Rc;
 
 pub fn nap2_compilation_unit(
     compilation_unit: &mut CompilationUnit,
     symbol_table: &SymbolTable,
+    symbol_tree: &SymbolTree,
     diagnostics: &mut Vec<DmDiagnostic>,
 ) {
     // TODO: check namespace for proper file name
     for use_statement in compilation_unit.use_statements_mut() {
-        nap2_use_statement(use_statement, symbol_table, diagnostics);
+        nap2_use_statement(use_statement, symbol_tree, diagnostics);
     }
 
     // TODO: declarations
 }
 
-fn nap2_use_statement(
-    use_statement: &mut UseStatement,
-    symbol_table: &SymbolTable,
+fn find_usable_symbol(
+    use_statement: &UseStatement,
+    identifier: &Identifier,
+    symbol_tree: &SymbolTree,
+) -> Option<UsableSymbol> {
+    let fqn_parts: Vec<&str> = {
+        let mut base: Vec<&str> = use_statement
+            .prefixes()
+            .map(|prefix| prefix.identifier().name())
+            .collect();
+        base.push(identifier.name());
+        base
+    };
+    symbol_tree
+        .find_interface(&fqn_parts)
+        .map(|interface_symbol| UsableSymbol::Interface(interface_symbol))
+        .or_else(|| {
+            symbol_tree
+                .find_class(&fqn_parts)
+                .map(|class_symbol| UsableSymbol::Class(class_symbol))
+        })
+        .or_else(|| {
+            symbol_tree
+                .find_function(&fqn_parts)
+                .map(|function_symbol| UsableSymbol::Function(function_symbol))
+        })
+}
+
+fn find_matching_concrete_use_symbol(
+    use_statement: &UseStatement,
+    identifier: &Identifier,
+) -> Option<Rc<RefCell<ConcreteUseSymbol>>> {
+    let base_fqn = use_statement_base_fqn(use_statement);
+    use_statement
+        .use_symbols()
+        .iter()
+        .find(|use_symbol| match use_symbol {
+            UseSymbol::Concrete(concrete_use_symbol) => {
+                let borrowed = concrete_use_symbol.borrow();
+                borrowed.base_fqn() == base_fqn && borrowed.declared_name() == identifier.name()
+            }
+            _ => false,
+        })
+        .map(|use_symbol| match use_symbol {
+            UseSymbol::Concrete(concrete) => concrete.clone(),
+            _ => panic!(),
+        })
+}
+
+fn handle_concrete_use(
+    use_statement: &UseStatement,
+    identifier: &Identifier,
+    symbol_tree: &SymbolTree,
     diagnostics: &mut Vec<DmDiagnostic>,
 ) {
-    let base_fqn = use_statement_base_fqn(use_statement);
-
-    let mut handle_concrete_use_symbol = |identifier: &Identifier| {
-        let fqn = format!("{}::{}", base_fqn, identifier.name());
-        match symbol_table.resolve_concrete_usable_by_fqn(&fqn) {
-            Ok(resolved_symbol) => match *use_statement.use_symbol().unwrap().borrow() {
-                UseSymbol::Concrete(ref concrete_use_symbol) => {
+    let maybe_usable_symbol = find_usable_symbol(use_statement, identifier, symbol_tree);
+    if let Some(usable_symbol) = maybe_usable_symbol {
+        let maybe_concrete_use_symbol =
+            find_matching_concrete_use_symbol(use_statement, identifier);
+        if let Some(concrete_use_symbol) = maybe_concrete_use_symbol {
             concrete_use_symbol
                 .borrow_mut()
-                        .set_resolved_symbol(resolved_symbol);
+                .set_resolved_symbol(usable_symbol);
+        } else {
+            panic!("Can't find matching ConcreteUseSymbol");
         }
-                _ => panic!("Unexpected symbol type"),
-            },
-            Err(lookup_error) => {
+    } else {
         handle_lookup_error(
-                    lookup_error,
-                    &fqn,
+            SymbolLookupError::NoDefinition,
+            &format!(
+                "{}::{}",
+                use_statement_base_fqn(use_statement),
+                identifier.name()
+            ),
             use_statement.file_id(),
             use_statement.range(),
             "Usable Symbol",
             diagnostics,
         );
     }
-        }
-    };
+}
 
+fn nap2_use_statement(
+    use_statement: &mut UseStatement,
+    symbol_tree: &SymbolTree,
+    diagnostics: &mut Vec<DmDiagnostic>,
+) {
     match use_statement.suffix() {
         UseStatementSuffix::Identifier(identifier) => {
-            handle_concrete_use_symbol(identifier);
+            handle_concrete_use(use_statement, identifier, symbol_tree, diagnostics);
         }
         UseStatementSuffix::Star => {
-            if let Err(error) = symbol_table.resolve_usable_star(&base_fqn) {
-                handle_lookup_error(
-                    error,
-                    &base_fqn,
-                    use_statement.file_id(),
-                    use_statement.range(),
-                    "Star Usable Symbol",
-                    diagnostics,
-                );
-            }
+            todo!("Resolve star symbols")
         }
         UseStatementSuffix::UseList(use_list) => {
             for identifier in use_list.identifiers() {
-                handle_concrete_use_symbol(identifier);
+                handle_concrete_use(use_statement, identifier, symbol_tree, diagnostics);
             }
         }
     }

src/name_analysis/symbol/class_symbol.rs

@@ -0,0 +1,40 @@
+use std::cell::RefCell;
+use std::collections::HashMap;
+use std::rc::Rc;
+use crate::name_analysis::symbol::class_member_symbol::ClassMemberSymbol;
+use crate::name_analysis::symbol::function_symbol::FunctionSymbol;
+
+#[derive(Debug)]
+pub struct ClassSymbol {
+    declared_name: Rc<String>,
+    fqn: Rc<String>,
+    members: HashMap<Rc<String>, Rc<RefCell<ClassMemberSymbol>>>,
+    functions: HashMap<Rc<String>, Rc<RefCell<FunctionSymbol>>>
+}
+
+impl ClassSymbol {
+    pub fn new(declared_name: &str, fqn: &str) -> Self {
+        Self {
+            declared_name: Rc::new(declared_name.to_string()),
+            fqn: Rc::new(fqn.to_string()),
+            members: HashMap::new(),
+            functions: HashMap::new(),
+        }
+    }
+    
+    pub fn declared_name(&self) -> &str {
+        &self.declared_name
+    }
+    
+    pub fn declared_name_owned(&self) -> Rc<String> {
+        self.declared_name.clone()
+    }
+    
+    pub fn fqn(&self) -> &str {
+        &self.fqn
+    }
+    
+    pub fn fqn_owned(&self) -> Rc<String> {
+        self.fqn.clone()
+    }
+}

src/name_analysis/symbol/interface_symbol.rs

@@ -0,0 +1,36 @@
+use std::collections::HashMap;
+use std::rc::Rc;
+use crate::name_analysis::symbol::function_symbol::FunctionSymbol;
+
+#[derive(Debug)]
+pub struct InterfaceSymbol {
+    declared_name: Rc<String>,
+    fqn: Rc<String>,
+    functions: HashMap<String, FunctionSymbol>,
+}
+
+impl InterfaceSymbol {
+    pub fn new(declared_name: &str, fqn: &str) -> Self {
+        Self {
+            declared_name: Rc::new(declared_name.to_string()),
+            fqn: Rc::new(fqn.to_string()),
+            functions: HashMap::new(),
+        }
+    }
+    
+    pub fn declared_name(&self) -> &str {
+        &self.declared_name
+    }
+    
+    pub fn declared_name_owned(&self) -> Rc<String> {
+        self.declared_name.clone()
+    }
+    
+    pub fn fqn(&self) -> &str {
+        &self.fqn
+    }
+    
+    pub fn fqn_owned(&self) -> Rc<String> {
+        self.fqn.clone()
+    }
+}

src/name_analysis/symbol/mod.rs

@@ -1,12 +1,14 @@
-pub(crate) mod class_member_symbol;
-pub(crate) mod function_symbol;
-pub(crate) mod module_symbol;
-pub(crate) mod parameter_symbol;
-pub(crate) mod source_definition;
-pub(crate) mod type_symbol;
-pub(crate) mod usable_symbol;
-pub(crate) mod use_symbol;
-pub(crate) mod variable_symbol;
+pub mod class_member_symbol;
+pub mod class_symbol;
+pub mod function_symbol;
+pub mod interface_symbol;
+pub mod module_symbol;
+pub mod parameter_symbol;
+pub mod source_definition;
+pub mod type_symbol;
+pub mod usable_symbol;
+pub mod use_symbol;
+pub mod variable_symbol;
 
 use crate::name_analysis::symbol::type_symbol::ConcreteTypeSymbol;
 use crate::name_analysis::symbol::use_symbol::UseSymbol;
@@ -40,7 +42,9 @@ impl Symbol {
             Symbol::Use(use_symbol) => use_symbol.source_definition(),
             Symbol::Module(module) => module.source_definition().cloned(),
             Symbol::Type(type_symbol) => type_symbol.source_definition().cloned(),
-            Symbol::ConcreteType(concrete_type_symbol) => concrete_type_symbol.borrow().source_definition().cloned(),
+            Symbol::ConcreteType(concrete_type_symbol) => {
+                concrete_type_symbol.borrow().source_definition().cloned()
+            }
             Symbol::Function(function_symbol) => function_symbol.source_definition().cloned(),
             Symbol::Parameter(parameter_symbol) => parameter_symbol.source_definition().cloned(),
             Symbol::Variable(variable_symbol) => variable_symbol.source_definition().cloned(),

src/name_analysis/symbol/usable_symbol.rs

@@ -1,10 +1,12 @@
+use crate::name_analysis::symbol::class_symbol::ClassSymbol;
 use crate::name_analysis::symbol::function_symbol::FunctionSymbol;
-use crate::name_analysis::symbol::type_symbol::{ConcreteTypeSymbol, TypeSymbol};
+use crate::name_analysis::symbol::interface_symbol::InterfaceSymbol;
 use std::cell::RefCell;
 use std::rc::Rc;
 
 #[derive(Clone, Debug)]
-pub enum ConcreteUsableSymbol {
-    Type(Rc<RefCell<ConcreteTypeSymbol>>),
+pub enum UsableSymbol {
+    Interface(Rc<RefCell<InterfaceSymbol>>),
+    Class(Rc<RefCell<ClassSymbol>>),
     Function(Rc<RefCell<FunctionSymbol>>),
 }

src/name_analysis/symbol/use_symbol.rs

@@ -1,5 +1,5 @@
 use crate::name_analysis::symbol::source_definition::SourceDefinition;
-use crate::name_analysis::symbol::usable_symbol::ConcreteUsableSymbol;
+use crate::name_analysis::symbol::usable_symbol::UsableSymbol;
 use std::cell::RefCell;
 use std::fmt::{Debug, Formatter};
 use std::rc::Rc;
@@ -24,7 +24,7 @@ pub struct ConcreteUseSymbol {
     base_fqn: String,
     declared_name: String,
     source_definition: Option<SourceDefinition>,
-    resolved_symbol: Option<ConcreteUsableSymbol>,
+    resolved_symbol: Option<UsableSymbol>,
 }
 
 impl ConcreteUseSymbol {
@@ -53,11 +53,11 @@ impl ConcreteUseSymbol {
         self.source_definition.as_ref()
     }
 
-    pub fn resolved_symbol(&self) -> Option<&ConcreteUsableSymbol> {
+    pub fn resolved_symbol(&self) -> Option<&UsableSymbol> {
         self.resolved_symbol.as_ref()
     }
 
-    pub fn set_resolved_symbol(&mut self, symbol: ConcreteUsableSymbol) {
+    pub fn set_resolved_symbol(&mut self, symbol: UsableSymbol) {
         self.resolved_symbol = Some(symbol);
     }
 }

src/name_analysis/symbol_table/mod.rs

@@ -2,8 +2,6 @@ use crate::name_analysis::symbol::class_member_symbol::ClassMemberSymbol;
 use crate::name_analysis::symbol::function_symbol::FunctionSymbol;
 use crate::name_analysis::symbol::module_symbol::ModuleSymbol;
 use crate::name_analysis::symbol::parameter_symbol::ParameterSymbol;
-use crate::name_analysis::symbol::type_symbol::ConcreteTypeSymbol;
-use crate::name_analysis::symbol::usable_symbol::ConcreteUsableSymbol;
 use crate::name_analysis::symbol::use_symbol::{ConcreteUseSymbol, StarUseSymbol, UseSymbol};
 use crate::name_analysis::symbol::variable_symbol::VariableSymbol;
 use crate::name_analysis::symbol::*;
@@ -11,7 +9,6 @@ use crate::name_analysis::symbol_table::SymbolInsertError::SymbolAlreadyDefined;
 use crate::name_analysis::symbol_table::SymbolLookupError::NoDefinition;
 use scope::Scope;
 use std::cell::RefCell;
-use std::collections::VecDeque;
 use std::fmt::Display;
 use std::ops::Deref;
 use std::rc::Rc;
@@ -82,10 +79,6 @@ impl SymbolTable {
             .cloned()
     }
 
-    fn find_current_scope_star_use_symbol(&self, base_fqn: &str) -> Option<&StarUseSymbol> {
-        self.current_scope().star_use_symbols().get(base_fqn)
-    }
-
     fn find_current_scope_module_symbol(&self, declared_name: &str) -> Option<&ModuleSymbol> {
         self.current_scope().module_symbols().get(declared_name)
     }
@@ -159,19 +152,11 @@ impl SymbolTable {
     pub fn insert_star_use_symbol(
         &mut self,
         star_use_symbol: StarUseSymbol,
-    ) -> Result<(), SymbolInsertError> {
-        if let Some(defined_symbol) =
-            self.find_current_scope_star_use_symbol(star_use_symbol.base_fqn())
-        {
-            Err(SymbolAlreadyDefined(Symbol::Use(UseSymbol::Star(
-                defined_symbol.clone(),
-            ))))
-        } else {
-            self.current_scope_mut()
-                .star_use_symbols_mut()
-                .insert(star_use_symbol.base_fqn().to_string(), star_use_symbol);
-            Ok(())
-        }
+    ) -> Result<Rc<RefCell<StarUseSymbol>>, SymbolInsertError> {
+        let inserted = self
+            .current_scope_mut()
+            .insert_star_use_symbol(star_use_symbol);
+        Ok(inserted)
     }
 
     pub fn insert_module_symbol(
@@ -190,27 +175,6 @@ impl SymbolTable {
         }
     }
 
-    fn find_current_scope_concrete_type_symbol(
-        &self,
-        declared_name: &str,
-    ) -> Option<Rc<RefCell<ConcreteTypeSymbol>>> {
-        self.current_scope().get_concrete_type_symbol(declared_name)
-    }
-
-    pub fn insert_concrete_type_symbol(
-        &mut self,
-        symbol: ConcreteTypeSymbol,
-    ) -> Result<(), SymbolInsertError> {
-        if let Some(defined_type) =
-            self.find_current_scope_concrete_type_symbol(symbol.declared_name())
-        {
-            Err(SymbolAlreadyDefined(Symbol::ConcreteType(defined_type)))
-        } else {
-            self.current_scope_mut().insert_concrete_type_symbol(symbol);
-            Ok(())
-        }
-    }
-
     pub fn insert_function_symbol(
         &mut self,
         function_symbol: FunctionSymbol,
@@ -334,39 +298,6 @@ impl SymbolTable {
         }
         Err(NoDefinition)
     }
-
-    pub fn resolve_concrete_usable_by_fqn(
-        &self,
-        fqn: &str,
-    ) -> Result<ConcreteUsableSymbol, SymbolLookupError> {
-        // breadth-first search, use a queue
-        let mut search_stack: VecDeque<usize> = VecDeque::new();
-        search_stack.push_back(0); // global scope
-
-        while let Some(scope_id) = search_stack.pop_front() {
-            let scope = &self.scopes[scope_id];
-            for child_id in scope.children() {
-                search_stack.push_back(child_id);
-            }
-
-            if let Some(concrete_type_symbol) = scope.get_concrete_type_symbol_by_fqn(fqn) {
-                return Ok(ConcreteUsableSymbol::Type(concrete_type_symbol));
-            }
-
-            // TODO: this is inefficient. Use a (cached) hash table of Fqn => Rc<RefCell<symbol>>
-            for function_symbol in scope.function_symbols().values() {
-                if function_symbol.fqn() == fqn {
-                    return Ok(ConcreteUsableSymbol::Function(todo!()));
-                }
-            }
-        }
-
-        Err(NoDefinition)
-    }
-
-    pub fn resolve_usable_star(&self, base_fqn: &str) -> Result<(), SymbolLookupError> {
-        todo!()
-    }
 }
 
 impl Display for SymbolTable {

src/name_analysis/symbol_table/scope.rs

@@ -1,8 +1,9 @@
 use crate::name_analysis::symbol::class_member_symbol::ClassMemberSymbol;
+use crate::name_analysis::symbol::class_symbol::ClassSymbol;
 use crate::name_analysis::symbol::function_symbol::FunctionSymbol;
+use crate::name_analysis::symbol::interface_symbol::InterfaceSymbol;
 use crate::name_analysis::symbol::module_symbol::ModuleSymbol;
 use crate::name_analysis::symbol::parameter_symbol::ParameterSymbol;
-use crate::name_analysis::symbol::type_symbol::{ConcreteTypeSymbol, TypeSymbol};
 use crate::name_analysis::symbol::use_symbol::{ConcreteUseSymbol, StarUseSymbol};
 use crate::name_analysis::symbol::variable_symbol::VariableSymbol;
 use std::cell::RefCell;
@@ -16,10 +17,10 @@ pub struct Scope {
     id: usize,
     children: Vec<usize>,
     concrete_use_symbols: HashMap<String, Rc<RefCell<ConcreteUseSymbol>>>,
-    star_use_symbols: HashMap<String, StarUseSymbol>,
+    star_use_symbols: HashMap<String, Rc<RefCell<StarUseSymbol>>>,
     module_symbols: HashMap<String, ModuleSymbol>,
-    concrete_type_symbols: HashMap<String, Rc<RefCell<ConcreteTypeSymbol>>>,
-    concrete_type_symbols_by_fqn: HashMap<String, Rc<RefCell<ConcreteTypeSymbol>>>,
+    interface_symbols: HashMap<Rc<String>, Rc<RefCell<InterfaceSymbol>>>,
+    class_symbols: HashMap<Rc<String>, Rc<RefCell<ClassSymbol>>>,
     function_symbols: HashMap<String, FunctionSymbol>,
     parameter_symbols: HashMap<String, ParameterSymbol>,
     variable_symbols: HashMap<String, VariableSymbol>,
@@ -36,8 +37,8 @@ impl Scope {
             concrete_use_symbols: HashMap::new(),
             star_use_symbols: HashMap::new(),
             module_symbols: HashMap::new(),
-            concrete_type_symbols: HashMap::new(),
-            concrete_type_symbols_by_fqn: HashMap::new(),
+            interface_symbols: HashMap::new(),
+            class_symbols: HashMap::new(),
             function_symbols: HashMap::new(),
             parameter_symbols: HashMap::new(),
             variable_symbols: HashMap::new(),
@@ -72,12 +73,10 @@ impl Scope {
         &mut self.concrete_use_symbols
     }
     
-    pub fn star_use_symbols(&self) -> &HashMap<String, StarUseSymbol> {
-        &self.star_use_symbols
-    }
-
-    pub fn star_use_symbols_mut(&mut self) -> &mut HashMap<String, StarUseSymbol> {
-        &mut self.star_use_symbols
+    pub fn insert_star_use_symbol(&mut self, symbol: StarUseSymbol) -> Rc<RefCell<StarUseSymbol>> {
+        let as_rc = Rc::new(RefCell::new(symbol));
+        self.star_use_symbols.insert(as_rc.borrow().base_fqn().to_string(), as_rc.clone());
+        as_rc.clone()
     }
 
     pub fn module_symbols(&self) -> &HashMap<String, ModuleSymbol> {
@@ -88,24 +87,25 @@ impl Scope {
         &mut self.module_symbols
     }
 
-    pub fn insert_concrete_type_symbol(&mut self, symbol: ConcreteTypeSymbol) {
-        let as_rc = Rc::new(RefCell::new(symbol));
-        self.concrete_type_symbols.insert(
-            as_rc.borrow().declared_name().to_string(),
-            as_rc.clone(),
-        );
-        self.concrete_type_symbols_by_fqn.insert(
-            as_rc.borrow().fqn().to_string(),
-            as_rc.clone(),
-        );
+    pub fn insert_interface_symbol(&mut self, symbol: InterfaceSymbol) {
+        self.interface_symbols
+            .insert(symbol.declared_name_owned(), Rc::new(RefCell::new(symbol)));
     }
 
-    pub fn get_concrete_type_symbol(&self, declared_name: &str) -> Option<Rc<RefCell<ConcreteTypeSymbol>>> {
-        self.concrete_type_symbols.get(declared_name).cloned()
+    pub fn get_interface_symbol(
+        &self,
+        declared_name: Rc<String>,
+    ) -> Option<Rc<RefCell<InterfaceSymbol>>> {
+        self.interface_symbols.get(&declared_name).cloned()
     }
 
-    pub fn get_concrete_type_symbol_by_fqn(&self, fqn: &str) -> Option<Rc<RefCell<ConcreteTypeSymbol>>> {
-        self.concrete_type_symbols_by_fqn.get(fqn).cloned()
+    pub fn insert_class_symbol(&mut self, symbol: ClassSymbol) {
+        self.class_symbols
+            .insert(symbol.declared_name_owned(), Rc::new(RefCell::new(symbol)));
+    }
+
+    pub fn get_class_symbol(&self, declared_name: Rc<String>) -> Option<Rc<RefCell<ClassSymbol>>> {
+        self.class_symbols.get(&declared_name).cloned()
     }
 
     pub fn function_symbols(&self) -> &HashMap<String, FunctionSymbol> {
@@ -165,7 +165,7 @@ impl Display for Scope {
             self.debug_name()
         )?;
         write_symbols!(f, self.concrete_use_symbols());
-        write_symbols!(f, self.star_use_symbols());
+        todo!("self.star_use_symbols");
         write_symbols!(f, self.module_symbols());
         todo!("self.concrete_type_symbols");
         write_symbols!(f, self.function_symbols());

src/name_analysis/symbol_tree.rs

@@ -0,0 +1,57 @@
+use std::cell::RefCell;
+use crate::name_analysis::symbol::class_symbol::ClassSymbol;
+use crate::name_analysis::symbol::function_symbol::FunctionSymbol;
+use crate::name_analysis::symbol::interface_symbol::InterfaceSymbol;
+use std::collections::HashMap;
+use std::rc::Rc;
+
+pub struct SymbolTree {
+    children: Box<HashMap<String, SymbolTree>>,
+    classes: Box<HashMap<String, Rc<RefCell<ClassSymbol>>>>,
+    interfaces: Box<HashMap<String, Rc<RefCell<InterfaceSymbol>>>>,
+    functions: Box<HashMap<String, Rc<RefCell<FunctionSymbol>>>>,
+}
+
+impl SymbolTree {
+    pub fn new() -> Self {
+        Self {
+            children: Box::new(HashMap::new()),
+            classes: Box::new(HashMap::new()),
+            interfaces: Box::new(HashMap::new()),
+            functions: Box::new(HashMap::new()),
+        }
+    }
+
+    pub fn find_class(&self, fqn_parts: &[&str]) -> Option<Rc<RefCell<ClassSymbol>>> {
+        match fqn_parts.len() {
+            0 => None,
+            1 => self.classes.get(fqn_parts[0]).cloned(),
+            _ => self
+                .children
+                .get(fqn_parts[0])
+                .and_then(|child_tree| child_tree.find_class(&fqn_parts[1..])),
+        }
+    }
+    
+    pub fn find_interface(&self, fqn_parts: &[&str]) -> Option<Rc<RefCell<InterfaceSymbol>>> {
+        match fqn_parts.len() {
+            0 => None,
+            1 => self.interfaces.get(fqn_parts[0]).cloned(),
+            _ => self
+                .children
+                .get(fqn_parts[0])
+                .and_then(|child_tree| child_tree.find_interface(&fqn_parts[1..])),
+        }
+    }
+    
+    pub fn find_function(&self, fqn_parts: &[&str]) -> Option<Rc<RefCell<FunctionSymbol>>> {
+        match fqn_parts.len() {
+            0 => None,
+            1 => self.functions.get(fqn_parts[0]).cloned(),
+            _ => self
+                .children
+                .get(fqn_parts[0])
+                .and_then(|child_tree| child_tree.find_function(&fqn_parts[1..])),
+        }
+    }
+}

src/name_analysis/util.rs

@@ -1,11 +1,68 @@
 use crate::ast::node::UseStatement;
+use crate::diagnostic::DmDiagnostic;
+use crate::name_analysis::symbol_table::{SymbolInsertError, SymbolLookupError};
+use codespan_reporting::diagnostic::{Diagnostic, Label};
+use std::range::Range;
 
-pub fn use_statement_base_fqn(
-    use_statement: &UseStatement
-) -> String {
+pub fn use_statement_base_fqn(use_statement: &UseStatement) -> String {
     use_statement
         .prefixes()
         .map(|prefix| prefix.identifier().name())
         .collect::<Vec<_>>()
         .join("::")
 }
+
+pub fn handle_insert_error(
+    err: SymbolInsertError,
+    error_symbol_name: &str,
+    error_file_id: usize,
+    error_range: Range<usize>,
+    symbol_types: &str,
+    diagnostics: &mut Vec<DmDiagnostic>,
+) {
+    match err {
+        SymbolInsertError::SymbolAlreadyDefined(s) => {
+            let mut diagnostic = Diagnostic::error()
+                .with_message(format!(
+                    "{} symbol '{}' already defined in the current scope.",
+                    symbol_types, error_symbol_name,
+                ))
+                .with_label(
+                    Label::primary(error_file_id, error_range)
+                        .with_message("Symbol duplicated here."),
+                );
+
+            if let Some(source_definition) = s.definition() {
+                diagnostic = diagnostic.with_label(
+                    Label::secondary(source_definition.file_id(), source_definition.range())
+                        .with_message("Symbol defined here."),
+                );
+            }
+
+            diagnostics.push(diagnostic);
+        }
+    }
+}
+
+pub fn handle_lookup_error(
+    err: SymbolLookupError,
+    error_symbol_name: &str,
+    error_file_id: usize,
+    error_range: Range<usize>,
+    symbol_types: &str,
+    diagnostics: &mut Vec<DmDiagnostic>,
+) {
+    match err {
+        SymbolLookupError::NoDefinition => {
+            let diagnostic = Diagnostic::error()
+                .with_message(format!(
+                    "No such {} symbol '{}' in scope.",
+                    symbol_types, error_symbol_name,
+                ))
+                .with_label(
+                    Label::primary(error_file_id, error_range).with_message("Symbol used here."),
+                );
+            diagnostics.push(diagnostic);
+        }
+    }
+}

src/parser/ast.yaml

@@ -249,9 +249,9 @@ UseStatement:
           special:
             kind: range
     fields:
-      - use_symbol:
+      - use_symbols:
           kind: UseSymbol
-          wrap: rc_ref_cell
+          vec: true
 UseStatementPrefix:
   struct:
     children: