start on type checking statements

compiler/ast/src/passes/visitor_director.rs

@@ -76,7 +76,6 @@ impl<'a, V: ExpressionVisitor<'a>> VisitorDirector<'a, V> {
 
     pub fn visit_call(&mut self, input: &'a CallExpression) {
         if let VisitResult::VisitChildren = self.visitor.visit_call(input) {
-            self.visit_expression(&input.function);
             for expr in input.arguments.iter() {
                 self.visit_expression(expr);
             }

compiler/passes/src/symbol_table/table.rs

@@ -16,7 +16,7 @@
 
 use std::fmt::Display;
 
-use leo_ast::Function;
+use leo_ast::{DefinitionStatement, Function, FunctionInput};
 use leo_errors::{AstError, Result};
 use leo_span::Symbol;
 
@@ -31,7 +31,7 @@ pub struct SymbolTable<'a> {
     functions: IndexMap<Symbol, &'a Function>,
     /// Variables represents functions variable definitions and input variables.
     /// This field is not populated till necessary.
-    variables: VariableSymbol<'a>,
+    pub(crate) variables: VariableSymbol<'a>,
 }
 
 impl<'a> SymbolTable<'a> {
@@ -48,15 +48,35 @@ impl<'a> SymbolTable<'a> {
         self.variables.clear();
     }
 
-    pub fn insert_fn(&mut self, symbol: Symbol, function: &'a Function) -> Result<()> {
+    pub fn insert_fn(&mut self, symbol: Symbol, insert: &'a Function) -> Result<()> {
         self.check_shadowing(&symbol)?;
-        self.functions.insert(symbol, function);
+        self.functions.insert(symbol, insert);
         Ok(())
     }
 
-    pub fn lookup_fn(&mut self, symbol: &Symbol) -> Option<&&'a Function> {
+    pub fn insert_fn_input(&mut self, symbol: Symbol, insert: &'a FunctionInput) -> Result<()> {
+        self.check_shadowing(&symbol)?;
+        self.variables.inputs.insert(symbol, insert);
+        Ok(())
+    }
+
+    pub fn insert_variable(&mut self, symbol: Symbol, insert: &'a DefinitionStatement) -> Result<()> {
+        self.check_shadowing(&symbol)?;
+        self.variables.variables.insert(symbol, insert);
+        Ok(())
+    }
+
+    pub fn lookup_fn(&self, symbol: &Symbol) -> Option<&&'a Function> {
         self.functions.get(symbol)
     }
+
+    pub fn lookup_fn_input(&self, symbol: &Symbol) -> Option<&&'a FunctionInput> {
+        self.variables.inputs.get(symbol)
+    }
+
+    pub fn lookup_var(&self, symbol: &Symbol) -> Option<&&'a DefinitionStatement> {
+        self.variables.variables.get(symbol)
+    }
 }
 
 impl<'a> Display for SymbolTable<'a> {

compiler/passes/src/symbol_table/variable_symbol.rs

@@ -17,7 +17,7 @@
 use std::fmt::Display;
 
 use indexmap::IndexMap;
-use leo_ast::{DefinitionStatement, FunctionInput, FunctionInputVariable};
+use leo_ast::{DefinitionStatement, FunctionInput, Node};
 use leo_errors::{AstError, Result};
 use leo_span::Symbol;
 
@@ -27,33 +27,20 @@ pub struct VariableSymbol<'a> {
     /// For example if we are in a if block inside a function.
     /// The parent would be the functions variables and inputs.
     /// This field is populated as necessary.
-    parent: Option<Box<VariableSymbol<'a>>>,
+    pub(crate) parent: Option<Box<VariableSymbol<'a>>>,
     /// The input variables defined in a scope.
     /// This field is populated as necessary.
-    inputs: IndexMap<Symbol, &'a FunctionInputVariable>,
+    pub(crate) inputs: IndexMap<Symbol, &'a FunctionInput>,
     /// The variables defined in a scope.
     /// This field is populated as necessary.
-    variables: IndexMap<Symbol, &'a DefinitionStatement>,
+    pub(crate) variables: IndexMap<Symbol, &'a DefinitionStatement>,
 }
 
 impl<'a> VariableSymbol<'a> {
-    pub fn new(parent: Option<Box<VariableSymbol<'a>>>, inputs: Vec<&'a FunctionInput>) -> Self {
-        Self {
-            parent,
-            inputs: inputs
-                .iter()
-                .map(|input| {
-                    let inner = input.get_variable();
-                    (inner.identifier.name, inner)
-                })
-                .collect(),
-            variables: IndexMap::new(),
-        }
-    }
-
     pub fn check_shadowing(&self, symbol: &Symbol) -> Result<()> {
         if let Some(input) = self.inputs.get(symbol) {
-            Err(AstError::shadowed_function_input(symbol, &input.span).into())
+            let span = input.span();
+            Err(AstError::shadowed_function_input(symbol, span).into())
         } else if let Some(var) = self.variables.get(symbol) {
             Err(AstError::shadowed_variable(symbol, &var.span).into())
         } else if let Some(parent) = &self.parent {

compiler/passes/src/type_checker/check.rs

@@ -15,28 +15,101 @@
 // along with the Leo library. If not, see <https://www.gnu.org/licenses/>.
 
 use leo_ast::*;
+use leo_errors::Result;
 
 use crate::TypeChecker;
 
+impl<'a> TypeChecker<'a> {
+    fn compare_types(&self, t1: Result<Option<Type>>, t2: Result<Option<Type>>) {
+        match (t1, t2) {
+            (Ok(Some(t1)), Ok(Some(t2))) if t1 != t2 => self.handler.emit_err(todo!()),
+            (Ok(Some(t)), Ok(None)) | (Ok(None), Ok(Some(t))) => self.handler.emit_err(todo!()),
+            (Err(err), Ok(None)) | (Ok(None), Err(err)) => self.handler.emit_err(err),
+            (Err(err1), Err(err2)) => {
+                self.handler.emit_err(err1);
+                self.handler.emit_err(err2);
+            }
+            _ => {}
+        }
+    }
+}
+
 impl<'a> ExpressionVisitor<'a> for TypeChecker<'a> {}
 
+// we can safely unwrap all self.parent instances because
+// statements should always have some parent block
 impl<'a> StatementVisitor<'a> for TypeChecker<'a> {
     fn visit_return(&mut self, input: &'a ReturnStatement) -> VisitResult {
         let parent = self.parent.unwrap();
+
         if let Some(func) = self.symbol_table.lookup_fn(&parent) {
-            // if func.get_type()? != input.get_type()? {
-            //     // self.handler.emit_err(err);
-            // }
+            self.compare_types(func.get_type(), input.get_type());
         }
 
         VisitResult::VisitChildren
     }
+
+    fn visit_definition(&mut self, input: &'a DefinitionStatement) -> VisitResult {
+        input.variable_names.iter().for_each(|v| {
+            if let Err(err) = self.symbol_table.insert_variable(v.identifier.name, input) {
+                self.handler.emit_err(err);
+            }
+        });
+
+        VisitResult::VisitChildren
+    }
+
+    fn visit_assign(&mut self, input: &'a AssignStatement) -> VisitResult {
+        let input_var = self.symbol_table.lookup_fn_input(&input.assignee.identifier.name);
+        let var = self.symbol_table.lookup_var(&input.assignee.identifier.name);
+
+        match (input_var, var) {
+            (Some(var), None) => {
+                self.compare_types(var.get_type(), input.value.get_type());
+            }
+            (None, Some(var)) => {
+                self.compare_types(var.get_type(), input.value.get_type());
+            }
+            (None, None) => self.handler.emit_err(todo!()),
+            // Don't have to error here as shadowing checks are done during insertions.
+            _ => {}
+        }
+
+        Default::default()
+    }
+
+    fn visit_conditional(&mut self, _input: &'a ConditionalStatement) -> VisitResult {
+        Default::default()
+    }
+
+    fn visit_iteration(&mut self, _input: &'a IterationStatement) -> VisitResult {
+        Default::default()
+    }
+
+    fn visit_console(&mut self, _input: &'a ConsoleStatement) -> VisitResult {
+        Default::default()
+    }
+
+    fn visit_expression_statement(&mut self, _input: &'a ExpressionStatement) -> VisitResult {
+        Default::default()
+    }
+
+    fn visit_block(&mut self, _input: &'a Block) -> VisitResult {
+        Default::default()
+    }
 }
 
 impl<'a> ProgramVisitor<'a> for TypeChecker<'a> {
     fn visit_function(&mut self, input: &'a Function) -> VisitResult {
         self.symbol_table.clear_variables();
         self.parent = Some(input.name());
+        input.input.iter().for_each(|i| {
+            let symbol = i.get_variable().identifier.name;
+            if let Err(err) = self.symbol_table.insert_fn_input(symbol, i) {
+                self.handler.emit_err(err);
+            }
+        });
+
         VisitResult::VisitChildren
     }
 }