Resolve local variables.

examples/worlds.dm

@@ -7,8 +7,8 @@ fn getWorlds() -> List<World> = [
 ]
 
 fn findWorldByColor(worlds: List<World>, color: String) -> String
-    worlds.find { it.color == color }
-        .map { it.name }
+    worlds.find { it -> it.color == color }
+        .map { it -> it.name }
         .expect "No world has the given color ${color}"
 end
 

src/name_analysis/gather.rs

@@ -20,7 +20,7 @@ use crate::name_analysis::symbol::type_symbol::{
 };
 use crate::name_analysis::symbol::use_symbol::{ConcreteUseSymbol, StarUseSymbol};
 use crate::name_analysis::symbol::variable_symbol::VariableSymbol;
-use crate::name_analysis::symbol_table::{SymbolInsertError, SymbolTable};
+use crate::name_analysis::symbol_table::{SymbolInsertError, SymbolLookupError, SymbolTable};
 use codespan_reporting::diagnostic::{Diagnostic, Label};
 use std::range::Range;
 
@@ -56,6 +56,29 @@ fn handle_insert_error(
     }
 }
 
+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);
+        }
+    }
+}
+
 fn gather_node_children<'a>(
     node: &'a dyn AstNode<'a>,
     symbol_table: &mut SymbolTable,
@@ -244,11 +267,8 @@ fn gather_node<'a>(
                 diagnostics,
             );
         }
-        AstNodeRef::LValue(l_value) => {
-            gather_node_children(l_value, symbol_table, fqn_context, scope_table, diagnostics);
-        }
         AstNodeRef::VariableUse(variable_use) => {
-            gather_variable_use(variable_use, symbol_table, scope_table);
+            gather_variable_use(variable_use, symbol_table, diagnostics);
         }
         AstNodeRef::TernaryExpression(ternary_expression) => {
             gather_ternary_expression(
@@ -1234,9 +1254,21 @@ fn gather_for_statement<'a>(
 fn gather_variable_use<'a>(
     variable_use: &'a VariableUse,
     symbol_table: &mut SymbolTable,
-    scope_table: &mut ScopeTable<'a>,
+    diagnostics: &mut Vec<DmDiagnostic>,
 ) {
-    scope_table.insert_variable_use_scope(variable_use, symbol_table.current_scope_id());
+    if let Err(lookup_error) = symbol_table.lookup_addressable_by_identifier(
+        variable_use.identifier().name(),
+        symbol_table.current_scope_id(),
+    ) {
+        handle_lookup_error(
+            lookup_error,
+            variable_use.identifier().name(),
+            variable_use.identifier().file_id(),
+            variable_use.identifier().range(),
+            "Variable",
+            diagnostics,
+        )
+    }
 }
 
 fn gather_ternary_expression<'a>(

src/name_analysis/symbol_table/mod.rs

@@ -45,8 +45,11 @@ impl SymbolTable {
 
     pub fn push_scope(&mut self, debug_name: &str) {
         let id = self.scopes.len();
-        self.scopes
-            .push(Scope::new(Some(self.current_scope_id), id, debug_name.to_string()));
+        self.scopes.push(Scope::new(
+            Some(self.current_scope_id),
+            id,
+            debug_name.to_string(),
+        ));
         self.current_scope_id = id;
     }
 
@@ -316,7 +319,61 @@ impl SymbolTable {
                 Some(&self.scopes[parent_id])
             } else {
                 None
+            };
+        }
+        Err(NoDefinition)
+    }
+
+    fn lookup_addressable_in_scope_by_identifier(
+        scope: &Scope,
+        identifier: &str,
+    ) -> Option<Symbol> {
+        scope
+            .variable_symbols()
+            .get(identifier)
+            .map(|variable_symbol| Symbol::Variable(variable_symbol.clone()))
+            .or_else(|| {
+                scope
+                    .parameter_symbols()
+                    .get(identifier)
+                    .map(|parameter_symbol| Symbol::Parameter(parameter_symbol.clone()))
+            })
+            .or_else(|| {
+                scope
+                    .class_member_symbols()
+                    .get(identifier)
+                    .map(|class_member_symbol| Symbol::ClassMember(class_member_symbol.clone()))
+            })
+            .or_else(|| {
+                scope
+                    .function_symbols()
+                    .get(identifier)
+                    .map(|function_symbol| Symbol::Function(function_symbol.clone()))
+            })
+            .or_else(|| {
+                scope
+                    .type_symbols()
+                    .get(identifier)
+                    .map(|type_symbol| Symbol::Type(type_symbol.clone()))
+            })
+    }
+
+    pub fn lookup_addressable_by_identifier(
+        &self,
+        identifier: &str,
+        scope_id: usize,
+    ) -> Result<Symbol, SymbolLookupError> {
+        let mut scope_opt = Some(&self.scopes[scope_id]);
+        while let Some(scope) = scope_opt {
+            if let Some(symbol) = Self::lookup_addressable_in_scope_by_identifier(scope, identifier)
+            {
+                return Ok(symbol);
             }
+            scope_opt = if let Some(parent_id) = scope.parent() {
+                Some(&self.scopes[parent_id])
+            } else {
+                None
+            };
         }
         Err(NoDefinition)
     }