Merge pull request #1786 from AleoHQ/feature/type-checking

[Impl] type-checking

compiler/ast/src/common/identifier.rs

@@ -14,6 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with the Leo library. If not, see <https://www.gnu.org/licenses/>.
 
+use leo_errors::Result;
 use leo_span::{Span, Symbol};
 
 use crate::Node;

compiler/ast/src/expression/binary.rs

@@ -47,20 +47,6 @@ pub enum BinaryOperation {
     Le,
     /// Lesser-than relation, i.e. `<`.
     Lt,
-    /// Bitwise-or inclusive, i.e., `|`.
-    BitOr,
-    /// Bitwise-and, i.e., `&`.
-    BitAnd,
-    /// Bitwise-or exclusive, i.e., `^`.
-    BitXor,
-    /// Shift-right, i.e `>>`.
-    Shr,
-    /// Unsigned shift-right, i.e `>>>`.
-    ShrSigned,
-    /// Shift-left, i.e `<<`.
-    Shl,
-    /// Modulus or remainder operation, i.e., `%`.
-    Mod,
 }
 
 /// The category a binary operation belongs to.
@@ -88,13 +74,6 @@ impl AsRef<str> for BinaryOperation {
             BinaryOperation::Gt => ">",
             BinaryOperation::Le => "<=",
             BinaryOperation::Lt => "<",
-            BinaryOperation::BitOr => "|",
-            BinaryOperation::BitAnd => "&",
-            BinaryOperation::BitXor => "^",
-            BinaryOperation::Shr => ">>",
-            BinaryOperation::ShrSigned => ">>>",
-            BinaryOperation::Shl => "<<",
-            BinaryOperation::Mod => "%",
         }
     }
 }
@@ -108,13 +87,6 @@ impl BinaryOperation {
             | BinaryOperation::Sub
             | BinaryOperation::Mul
             | BinaryOperation::Div
-            | BinaryOperation::BitOr
-            | BinaryOperation::BitAnd
-            | BinaryOperation::BitXor
-            | BinaryOperation::Shr
-            | BinaryOperation::ShrSigned
-            | BinaryOperation::Shl
-            | BinaryOperation::Mod
             | BinaryOperation::Pow => BinaryOperationClass::Numeric,
             BinaryOperation::Or
             | BinaryOperation::And

compiler/ast/src/expression/mod.rs

@@ -15,7 +15,6 @@
 // along with the Leo library. If not, see <https://www.gnu.org/licenses/>.
 
 use crate::{GroupValue, Identifier, IntegerType, Node};
-
 use leo_span::Span;
 
 use serde::{Deserialize, Serialize};

compiler/ast/src/expression/unary.rs

@@ -24,9 +24,6 @@ pub enum UnaryOperation {
     Not,
     /// The arithmetic negation operator, i.e., `-`.
     Negate,
-    /// The bitwise negation operator, i.e., `~`.
-    /// For example, it transforms `1010` to `0101`.
-    BitNot,
 }
 
 impl AsRef<str> for UnaryOperation {
@@ -34,7 +31,6 @@ impl AsRef<str> for UnaryOperation {
         match self {
             UnaryOperation::Not => "!",
             UnaryOperation::Negate => "-",
-            UnaryOperation::BitNot => "~",
         }
     }
 }

compiler/ast/src/expression/value.rs

@@ -33,8 +33,6 @@ pub enum ValueExpression {
     /// A group literal, either product or affine.
     /// For example, `42group` or `(12, 52)group`.
     Group(Box<GroupValue>),
-    /// A negated non-integer literal, e.g., `-4.2`.
-    Implicit(String, #[serde(with = "leo_span::span_json")] Span),
     /// An integer literal, e.g., `42`.
     Integer(IntegerType, String, #[serde(with = "leo_span::span_json")] Span),
     /// A string literal, e.g., `"foobar"`.
@@ -49,7 +47,6 @@ impl fmt::Display for ValueExpression {
             Boolean(boolean, _) => write!(f, "{}", boolean),
             Char(character) => write!(f, "{}", character),
             Field(field, _) => write!(f, "{}", field),
-            Implicit(implicit, _) => write!(f, "{}", implicit),
             Integer(type_, value, _) => write!(f, "{}{}", value, type_),
             Group(group) => write!(f, "{}", group),
             String(string, _) => {
@@ -66,12 +63,7 @@ impl Node for ValueExpression {
     fn span(&self) -> &Span {
         use ValueExpression::*;
         match &self {
-            Address(_, span)
-            | Boolean(_, span)
-            | Field(_, span)
-            | Implicit(_, span)
-            | Integer(_, _, span)
-            | String(_, span) => span,
+            Address(_, span) | Boolean(_, span) | Field(_, span) | Integer(_, _, span) | String(_, span) => span,
             Char(character) => &character.span,
             Group(group) => match &**group {
                 GroupValue::Single(_, span) => span,
@@ -83,12 +75,9 @@ impl Node for ValueExpression {
     fn set_span(&mut self, new_span: Span) {
         use ValueExpression::*;
         match self {
-            Address(_, span)
-            | Boolean(_, span)
-            | Field(_, span)
-            | Implicit(_, span)
-            | Integer(_, _, span)
-            | String(_, span) => *span = new_span,
+            Address(_, span) | Boolean(_, span) | Field(_, span) | Integer(_, _, span) | String(_, span) => {
+                *span = new_span
+            }
             Char(character) => character.span = new_span,
             Group(group) => match &mut **group {
                 GroupValue::Single(_, span) => *span = new_span,

compiler/ast/src/functions/input/function_input.rs

@@ -47,7 +47,7 @@ pub struct FunctionInputVariable {
     /// The mode of the function parameter.
     mode: ParamMode,
     /// What's the parameter's type?
-    type_: Type,
+    pub type_: Type,
     /// The parameters span from any annotations to its type.
     pub span: Span,
 }
@@ -65,10 +65,6 @@ impl FunctionInputVariable {
     pub fn mode(&self) -> ParamMode {
         self.mode
     }
-
-    pub fn type_(&self) -> Type {
-        self.type_.clone()
-    }
 }
 
 impl FunctionInputVariable {

compiler/ast/src/input/input_value.rs

@@ -42,11 +42,8 @@ impl TryFrom<(Type, Expression)> for InputValue {
                         Self::Boolean(bool_value)
                     }
                     (Type::Char, ValueExpression::Char(value)) => Self::Char(value),
-                    (Type::Field, ValueExpression::Field(value, _) | ValueExpression::Implicit(value, _)) => {
-                        Self::Field(value)
-                    }
+                    (Type::Field, ValueExpression::Field(value, _)) => Self::Field(value),
                     (Type::Group, ValueExpression::Group(value)) => Self::Group(*value),
-                    (Type::IntegerType(type_), ValueExpression::Implicit(value, _)) => Self::Integer(type_, value),
                     (Type::IntegerType(expected), ValueExpression::Integer(actual, value, span)) => {
                         if expected == actual {
                             Self::Integer(expected, value)

compiler/ast/src/passes/reconstructing_director.rs

@@ -275,7 +275,7 @@ impl<R: ReconstructingReducer> ReconstructingDirector<R> {
         variable: &FunctionInputVariable,
     ) -> Result<FunctionInputVariable> {
         let identifier = self.reduce_identifier(&variable.identifier)?;
-        let type_ = self.reduce_type(&variable.type_(), &variable.span)?;
+        let type_ = self.reduce_type(&variable.type_, &variable.span)?;
 
         self.reducer.reduce_function_input_variable(variable, identifier, type_)
     }

compiler/ast/src/passes/visitor_director.rs

@@ -76,10 +76,7 @@ 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);
-            }
+            input.arguments.iter().for_each(|expr| self.visit_expression(expr));
         }
     }
 }
@@ -138,8 +135,11 @@ impl<'a, V: ExpressionVisitor<'a> + StatementVisitor<'a>> VisitorDirector<'a, V>
 
     pub fn visit_console(&mut self, input: &'a ConsoleStatement) {
         if let VisitResult::VisitChildren = self.visitor.visit_console(input) {
-            if let ConsoleFunction::Assert(expr) = &input.function {
-                self.visit_expression(expr);
+            match &input.function {
+                ConsoleFunction::Assert(expr) => self.visit_expression(expr),
+                ConsoleFunction::Error(fmt) | ConsoleFunction::Log(fmt) => {
+                    fmt.parameters.iter().for_each(|expr| self.visit_expression(expr));
+                }
             }
         }
     }
@@ -152,9 +152,7 @@ impl<'a, V: ExpressionVisitor<'a> + StatementVisitor<'a>> VisitorDirector<'a, V>
 
     pub fn visit_block(&mut self, input: &'a Block) {
         if let VisitResult::VisitChildren = self.visitor.visit_block(input) {
-            for stmt in input.statements.iter() {
-                self.visit_statement(stmt);
-            }
+            input.statements.iter().for_each(|stmt| self.visit_statement(stmt));
         }
     }
 }
@@ -162,9 +160,10 @@ impl<'a, V: ExpressionVisitor<'a> + StatementVisitor<'a>> VisitorDirector<'a, V>
 impl<'a, V: ExpressionVisitor<'a> + ProgramVisitor<'a> + StatementVisitor<'a>> VisitorDirector<'a, V> {
     pub fn visit_program(&mut self, input: &'a Program) {
         if let VisitResult::VisitChildren = self.visitor.visit_program(input) {
-            for function in input.functions.values() {
-                self.visit_function(function);
-            }
+            input
+                .functions
+                .values()
+                .for_each(|function| self.visit_function(function));
         }
     }
 

compiler/ast/src/statements/assign/mod.rs

@@ -15,7 +15,6 @@
 // along with the Leo library. If not, see <https://www.gnu.org/licenses/>.
 
 use crate::{Expression, Node};
-
 use leo_span::Span;
 
 use serde::{Deserialize, Serialize};

compiler/compiler/src/lib.rs

@@ -130,6 +130,8 @@ impl<'a> Compiler<'a> {
     fn compiler_stages(&self) -> Result<SymbolTable<'_>> {
         let symbol_table = CreateSymbolTable::do_pass((&self.ast, self.handler))?;
 
+        TypeChecker::do_pass((&self.ast, &mut symbol_table.clone(), self.handler))?;
+
         Ok(symbol_table)
     }
 

compiler/compiler/src/test.rs

@@ -86,13 +86,13 @@ impl Namespace for CompileNamespace {
 #[derive(Deserialize, PartialEq, Serialize)]
 struct OutputItem {
     pub initial_input_ast: String,
-    pub symbol_table: String,
 }
 
 #[derive(Deserialize, PartialEq, Serialize)]
 struct CompileOutput {
     pub output: Vec<OutputItem>,
     pub initial_ast: String,
+    pub symbol_table: String,
 }
 
 /// Get the path of the `input_file` given in `input` into `list`.
@@ -102,6 +102,12 @@ fn get_input_file_paths(list: &mut Vec<PathBuf>, test: &Test, input: &Value) {
         let mut input_file = input_file;
         input_file.push(input.as_str().expect("input_file was not a string or array"));
         list.push(input_file.clone());
+    } else if let Some(seq) = input.as_sequence() {
+        for name in seq {
+            let mut input_file = input_file.clone();
+            input_file.push(name.as_str().expect("input_file was not a string"));
+            list.push(input_file.clone());
+        }
     }
 }
 
@@ -116,11 +122,7 @@ fn collect_all_inputs(test: &Test) -> Result<Vec<PathBuf>, String> {
     Ok(list)
 }
 
-fn compile_and_process<'a>(
-    parsed: &'a mut Compiler<'a>,
-    input_file_path: PathBuf,
-) -> Result<SymbolTable<'a>, LeoError> {
-    parsed.parse_input(input_file_path)?;
+fn compile_and_process<'a>(parsed: &'a mut Compiler<'a>) -> Result<SymbolTable<'a>, LeoError> {
     parsed.compiler_stages()
 }
 
@@ -176,23 +178,28 @@ fn run_test(test: Test, handler: &Handler, err_buf: &BufferEmitter) -> Result<Va
         cwd.join(&val.as_str().unwrap())
     });
 
-    let parsed = handler.extend_if_error(parse_program(handler, &test.content, cwd))?;
+    let mut parsed = handler.extend_if_error(parse_program(handler, &test.content, cwd))?;
 
     // (name, content)
     let inputs = buffer_if_err(err_buf, collect_all_inputs(&test))?;
 
     let mut output_items = Vec::with_capacity(inputs.len());
 
+    if inputs.is_empty() {
+        output_items.push(OutputItem {
+            initial_input_ast: "no input".to_string(),
+        });
+    } else {
         for input in inputs {
             let mut parsed = parsed.clone();
-        let symbol_table = handler.extend_if_error(compile_and_process(&mut parsed, input))?;
+            handler.extend_if_error(parsed.parse_input(input))?;
             let initial_input_ast = hash_file("/tmp/output/inital_input_ast.json");
 
-        output_items.push(OutputItem {
-            initial_input_ast,
-            symbol_table: hash_content(&symbol_table.to_string()),
-        });
+            output_items.push(OutputItem { initial_input_ast });
         }
+    }
+
+    let symbol_table = handler.extend_if_error(compile_and_process(&mut parsed))?;
 
     let initial_ast = hash_file("/tmp/output/initial_ast.json");
 
@@ -203,6 +210,7 @@ fn run_test(test: Test, handler: &Handler, err_buf: &BufferEmitter) -> Result<Va
     let final_output = CompileOutput {
         output: output_items,
         initial_ast,
+        symbol_table: hash_content(&symbol_table.to_string()),
     };
     Ok(serde_yaml::to_value(&final_output).expect("serialization failed"))
 }

compiler/parser/src/parser/type_.rs

@@ -32,6 +32,7 @@ pub(crate) const TYPE_TOKENS: &[Token] = &[
     Token::Group,
     Token::Address,
     Token::Bool,
+    Token::Char,
 ];
 
 impl ParserContext<'_> {

compiler/parser/src/test.rs

@@ -76,10 +76,6 @@ fn with_handler<T>(
     Ok(parsed)
 }
 
-fn implicit_value_expr() -> Expression {
-    Expression::Value(ValueExpression::Implicit("".into(), Span::default()))
-}
-
 fn tokenize(test: Test) -> Result<Vec<SpannedToken>, String> {
     tokenizer::tokenize("test", &test.content).map_err(|x| x.to_string())
 }
@@ -105,7 +101,7 @@ impl Namespace for ParseExpressionNamespace {
         create_session_if_not_set_then(|_| {
             let tokenizer = tokenize(test)?;
             if all_are_comments(&tokenizer) {
-                return Ok(yaml_or_fail(implicit_value_expr()));
+                return Ok(yaml_or_fail(""));
             }
             with_handler(tokenizer, |p| p.parse_expression()).map(yaml_or_fail)
         })
@@ -124,7 +120,7 @@ impl Namespace for ParseStatementNamespace {
             let tokenizer = tokenize(test)?;
             if all_are_comments(&tokenizer) {
                 return Ok(yaml_or_fail(Statement::Expression(ExpressionStatement {
-                    expression: implicit_value_expr(),
+                    expression: Expression::Value(ValueExpression::String(Vec::new(), Default::default())),
                     span: Span::default(),
                 })));
             }

compiler/passes/src/lib.rs

@@ -16,7 +16,7 @@
 
 #![doc = include_str!("../README.md")]
 
-// disable
+// Temporarily disable canonicalization.
 /* pub mod canonicalization;
 pub use canonicalization::*;
  */
@@ -31,3 +31,6 @@ pub use self::pass::*;
 
 pub mod symbol_table;
 pub use symbol_table::*;
+
+pub mod type_checker;
+pub use type_checker::*;

compiler/passes/src/symbol_table/mod.rs

@@ -20,6 +20,9 @@ pub use create::*;
 pub mod table;
 pub use table::*;
 
+pub mod variable_scope;
+pub use variable_scope::*;
+
 pub mod variable_symbol;
 pub use variable_symbol::*;
 

compiler/passes/src/symbol_table/table.rs

@@ -22,7 +22,7 @@ use leo_span::Symbol;
 
 use indexmap::IndexMap;
 
-use crate::VariableSymbol;
+use crate::{VariableScope, VariableSymbol};
 
 #[derive(Clone, Debug, Default, Eq, PartialEq)]
 pub struct SymbolTable<'a> {
@@ -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: VariableScope<'a>,
 }
 
 impl<'a> SymbolTable<'a> {
@@ -48,11 +48,39 @@ 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 insert_variable(&mut self, symbol: Symbol, insert: VariableSymbol<'a>) -> 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_variable(&self, symbol: &Symbol) -> Option<&VariableSymbol<'a>> {
+        self.variables.lookup_variable(symbol)
+    }
+
+    pub fn push_variable_scope(&mut self) {
+        let current_scope = self.variables.clone();
+        self.variables = VariableScope {
+            parent: Some(Box::new(current_scope)),
+            variables: Default::default(),
+        };
+    }
+
+    pub fn pop_variable_scope(&mut self) {
+        let parent = self.variables.parent.clone().unwrap();
+
+        self.variables = *parent;
+    }
 }
 
 impl<'a> Display for SymbolTable<'a> {

compiler/passes/src/symbol_table/variable_scope.rs

@@ -0,0 +1,78 @@
+// Copyright (C) 2019-2022 Aleo Systems Inc.
+// This file is part of the Leo library.
+
+// The Leo library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// The Leo library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with the Leo library. If not, see <https://www.gnu.org/licenses/>.
+
+use std::fmt::Display;
+
+use indexmap::IndexMap;
+use leo_errors::{AstError, Result};
+use leo_span::Symbol;
+
+use crate::VariableSymbol;
+
+#[derive(Clone, Debug, Default, Eq, PartialEq)]
+pub struct VariableScope<'a> {
+    /// The parent scope of variables if it exists.
+    /// 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.
+    pub(crate) parent: Option<Box<VariableScope<'a>>>,
+    /// The variables defined in a scope.
+    /// This field is populated as necessary.
+    pub(crate) variables: IndexMap<Symbol, VariableSymbol<'a>>,
+}
+
+impl<'a> VariableScope<'a> {
+    pub fn check_shadowing(&self, symbol: &Symbol) -> Result<()> {
+        if let Some(var) = self.variables.get(symbol) {
+            Err(AstError::shadowed_variable(symbol, var.span).into())
+        } else if let Some(parent) = &self.parent {
+            parent.check_shadowing(symbol)
+        } else {
+            Ok(())
+        }
+    }
+
+    pub fn clear(&mut self) {
+        self.parent = None;
+        self.variables.clear();
+    }
+
+    pub fn lookup_variable(&self, symbol: &Symbol) -> Option<&VariableSymbol<'a>> {
+        if let Some(var) = self.variables.get(symbol) {
+            Some(var)
+        } else if let Some(parent) = &self.parent {
+            parent.lookup_variable(symbol)
+        } else {
+            None
+        }
+    }
+}
+
+impl<'a> Display for VariableScope<'a> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "VariableScope")?;
+        self.parent
+            .as_ref()
+            .map(|parent| write!(f, "parent {parent}"))
+            .transpose()?;
+
+        for (sym, var) in self.variables.iter() {
+            write!(f, "{sym} {var}")?;
+        }
+
+        Ok(())
+    }
+}

compiler/passes/src/symbol_table/variable_symbol.rs

@@ -16,76 +16,38 @@
 
 use std::fmt::Display;
 
-use indexmap::IndexMap;
-use leo_ast::{DefinitionStatement, FunctionInput, FunctionInputVariable};
-use leo_errors::{AstError, Result};
-use leo_span::Symbol;
+use leo_ast::{ParamMode, Type};
+use leo_span::Span;
 
-#[derive(Clone, Debug, Default, Eq, PartialEq)]
-pub struct VariableSymbol<'a> {
-    /// The parent scope of variables if it exists.
-    /// 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>>>,
-    /// The input variables defined in a scope.
-    /// This field is populated as necessary.
-    inputs: IndexMap<Symbol, &'a FunctionInputVariable>,
-    /// The variables defined in a scope.
-    /// This field is populated as necessary.
-    variables: IndexMap<Symbol, &'a DefinitionStatement>,
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub enum Declaration {
+    Const,
+    Input(ParamMode),
+    Mut,
 }
 
-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(),
-        }
-    }
+impl Display for Declaration {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        use Declaration::*;
 
-    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())
-        } else if let Some(var) = self.variables.get(symbol) {
-            Err(AstError::shadowed_variable(symbol, &var.span).into())
-        } else if let Some(parent) = &self.parent {
-            parent.check_shadowing(symbol)
-        } else {
-            Ok(())
+        match self {
+            Const => write!(f, "const var"),
+            Input(m) => write!(f, "{m} input"),
+            Mut => write!(f, "mut var"),
         }
     }
+}
 
-    pub fn clear(&mut self) {
-        self.parent = None;
-        self.inputs.clear();
-        self.variables.clear();
-    }
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub struct VariableSymbol<'a> {
+    pub type_: &'a Type,
+    pub span: &'a Span,
+    pub declaration: Declaration,
 }
 
 impl<'a> Display for VariableSymbol<'a> {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "VariableSymbol")?;
-        self.parent
-            .as_ref()
-            .map(|parent| write!(f, "parent {parent}"))
-            .transpose()?;
-
-        for input in self.inputs.values() {
-            write!(f, "{input}")?;
-        }
-
-        for var in self.variables.values() {
-            write!(f, "{var}")?;
-        }
-
+        write!(f, "{}: {}", self.declaration, self.type_)?;
         Ok(())
     }
 }

compiler/passes/src/type_checker/check_expressions.rs

@@ -0,0 +1,317 @@
+// Copyright (C) 2019-2022 Aleo Systems Inc.
+// This file is part of the Leo library.
+
+// The Leo library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// The Leo library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with the Leo library. If not, see <https://www.gnu.org/licenses/>.
+
+use leo_ast::*;
+use leo_errors::TypeCheckerError;
+use leo_span::Span;
+
+use crate::TypeChecker;
+
+fn return_incorrect_type(t1: Option<Type>, t2: Option<Type>, expected: Option<Type>) -> Option<Type> {
+    match (t1, t2) {
+        (Some(t1), Some(t2)) if t1 == t2 => Some(t1),
+        (Some(t1), Some(t2)) => {
+            if let Some(expected) = expected {
+                if t1 != expected {
+                    Some(t1)
+                } else {
+                    Some(t2)
+                }
+            } else {
+                Some(t1)
+            }
+        }
+        (None, Some(_)) | (Some(_), None) | (None, None) => None,
+    }
+}
+
+impl<'a> TypeChecker<'a> {
+    pub(crate) fn compare_expr_type(&mut self, expr: &Expression, expected: Option<Type>, span: &Span) -> Option<Type> {
+        match expr {
+            Expression::Identifier(ident) => {
+                if let Some(var) = self.symbol_table.lookup_variable(&ident.name) {
+                    Some(self.assert_type(var.type_.clone(), expected, span))
+                } else {
+                    self.handler
+                        .emit_err(TypeCheckerError::unknown_sym("variable", ident.name, span).into());
+                    None
+                }
+            }
+            Expression::Value(value) => match value {
+                ValueExpression::Address(_, _) => Some(self.assert_type(Type::Address, expected, value.span())),
+                ValueExpression::Boolean(_, _) => Some(self.assert_type(Type::Boolean, expected, value.span())),
+                ValueExpression::Char(_) => Some(self.assert_type(Type::Char, expected, value.span())),
+                ValueExpression::Field(_, _) => Some(self.assert_type(Type::Field, expected, value.span())),
+                ValueExpression::Integer(type_, str_content, _) => {
+                    match type_ {
+                        IntegerType::I8 => {
+                            let int = if self.negate {
+                                self.negate = false;
+                                format!("-{str_content}")
+                            } else {
+                                str_content.clone()
+                            };
+
+                            if int.parse::<i8>().is_err() {
+                                self.handler
+                                    .emit_err(TypeCheckerError::invalid_int_value(int, "i8", value.span()).into());
+                            }
+                        }
+                        IntegerType::I16 => {
+                            let int = if self.negate {
+                                self.negate = false;
+                                format!("-{str_content}")
+                            } else {
+                                str_content.clone()
+                            };
+
+                            if int.parse::<i16>().is_err() {
+                                self.handler
+                                    .emit_err(TypeCheckerError::invalid_int_value(int, "i16", value.span()).into());
+                            }
+                        }
+                        IntegerType::I32 => {
+                            let int = if self.negate {
+                                self.negate = false;
+                                format!("-{str_content}")
+                            } else {
+                                str_content.clone()
+                            };
+
+                            if int.parse::<i32>().is_err() {
+                                self.handler
+                                    .emit_err(TypeCheckerError::invalid_int_value(int, "i32", value.span()).into());
+                            }
+                        }
+                        IntegerType::I64 => {
+                            let int = if self.negate {
+                                self.negate = false;
+                                format!("-{str_content}")
+                            } else {
+                                str_content.clone()
+                            };
+
+                            if int.parse::<i64>().is_err() {
+                                self.handler
+                                    .emit_err(TypeCheckerError::invalid_int_value(int, "i64", value.span()).into());
+                            }
+                        }
+                        IntegerType::I128 => {
+                            let int = if self.negate {
+                                self.negate = false;
+                                format!("-{str_content}")
+                            } else {
+                                str_content.clone()
+                            };
+
+                            if int.parse::<i128>().is_err() {
+                                self.handler
+                                    .emit_err(TypeCheckerError::invalid_int_value(int, "i128", value.span()).into());
+                            }
+                        }
+
+                        IntegerType::U8 if str_content.parse::<u8>().is_err() => self
+                            .handler
+                            .emit_err(TypeCheckerError::invalid_int_value(str_content, "u8", value.span()).into()),
+                        IntegerType::U16 if str_content.parse::<u16>().is_err() => self
+                            .handler
+                            .emit_err(TypeCheckerError::invalid_int_value(str_content, "u16", value.span()).into()),
+                        IntegerType::U32 if str_content.parse::<u32>().is_err() => self
+                            .handler
+                            .emit_err(TypeCheckerError::invalid_int_value(str_content, "u32", value.span()).into()),
+                        IntegerType::U64 if str_content.parse::<u64>().is_err() => self
+                            .handler
+                            .emit_err(TypeCheckerError::invalid_int_value(str_content, "u64", value.span()).into()),
+                        IntegerType::U128 if str_content.parse::<u128>().is_err() => self
+                            .handler
+                            .emit_err(TypeCheckerError::invalid_int_value(str_content, "u128", value.span()).into()),
+                        _ => {}
+                    }
+                    Some(self.assert_type(Type::IntegerType(*type_), expected, value.span()))
+                }
+                ValueExpression::Group(_) => Some(self.assert_type(Type::Group, expected, value.span())),
+                ValueExpression::String(_, _) => unreachable!("String types are not reachable"),
+            },
+            Expression::Binary(binary) => match binary.op {
+                BinaryOperation::And | BinaryOperation::Or => {
+                    self.assert_type(Type::Boolean, expected.clone(), binary.span());
+                    let t1 = self.compare_expr_type(&binary.left, expected.clone(), binary.left.span());
+                    let t2 = self.compare_expr_type(&binary.right, expected.clone(), binary.right.span());
+
+                    return_incorrect_type(t1, t2, expected)
+                }
+                BinaryOperation::Add | BinaryOperation::Sub => {
+                    self.assert_arith_type(expected.clone(), binary.span());
+                    let t1 = self.compare_expr_type(&binary.left, expected.clone(), binary.left.span());
+                    let t2 = self.compare_expr_type(&binary.right, expected.clone(), binary.right.span());
+
+                    return_incorrect_type(t1, t2, expected)
+                }
+                BinaryOperation::Mul => {
+                    self.assert_arith_type(expected.clone(), binary.span());
+
+                    let t1 = self.compare_expr_type(&binary.left, None, binary.left.span());
+                    let t2 = self.compare_expr_type(&binary.right, None, binary.right.span());
+
+                    match (t1.as_ref(), t2.as_ref()) {
+                        (Some(Type::Group), Some(other)) | (Some(other), Some(Type::Group)) => {
+                            self.assert_int_type(Some(other.clone()), binary.span());
+                            Some(Type::Group)
+                        }
+                        _ => return_incorrect_type(t1, t2, expected),
+                    }
+                }
+                BinaryOperation::Div => {
+                    self.assert_field_or_int_type(expected.clone(), binary.span());
+
+                    let t1 = self.compare_expr_type(&binary.left, expected.clone(), binary.left.span());
+                    let t2 = self.compare_expr_type(&binary.right, expected.clone(), binary.right.span());
+                    return_incorrect_type(t1, t2, expected)
+                }
+                BinaryOperation::Pow => {
+                    let t1 = self.compare_expr_type(&binary.left, None, binary.left.span());
+                    let t2 = self.compare_expr_type(&binary.right, None, binary.right.span());
+
+                    match (t1.as_ref(), t2.as_ref()) {
+                        // Type A must be an int.
+                        // Type B must be a unsigned int.
+                        (Some(Type::IntegerType(_)), Some(Type::IntegerType(itype))) if !itype.is_signed() => {
+                            self.assert_type(t1.clone().unwrap(), expected, binary.span());
+                        }
+                        // Type A was an int.
+                        // But Type B was not a unsigned int.
+                        (Some(Type::IntegerType(_)), Some(t)) => {
+                            self.handler.emit_err(
+                                TypeCheckerError::incorrect_pow_exponent_type("unsigned int", t, binary.right.span())
+                                    .into(),
+                            );
+                        }
+                        // Type A must be a field.
+                        // Type B must be an int.
+                        (Some(Type::Field), Some(Type::IntegerType(_))) => {
+                            self.assert_type(Type::Field, expected, binary.span());
+                        }
+                        // Type A was a field.
+                        // But Type B was not an int.
+                        (Some(Type::Field), Some(t)) => {
+                            self.handler.emit_err(
+                                TypeCheckerError::incorrect_pow_exponent_type("int", t, binary.right.span()).into(),
+                            );
+                        }
+                        // The base is some type thats not an int or field.
+                        (Some(t), _) => {
+                            self.handler
+                                .emit_err(TypeCheckerError::incorrect_pow_base_type(t, binary.left.span()).into());
+                        }
+                        _ => {}
+                    }
+
+                    t1
+                }
+                BinaryOperation::Eq | BinaryOperation::Ne => {
+                    self.assert_type(Type::Boolean, expected.clone(), binary.span());
+
+                    let t1 = self.compare_expr_type(&binary.left, None, binary.left.span());
+                    let t2 = self.compare_expr_type(&binary.right, None, binary.right.span());
+
+                    return_incorrect_type(t1, t2, expected)
+                }
+                BinaryOperation::Lt | BinaryOperation::Gt | BinaryOperation::Le | BinaryOperation::Ge => {
+                    self.assert_type(Type::Boolean, expected.clone(), binary.span());
+
+                    let t1 = self.compare_expr_type(&binary.left, None, binary.left.span());
+                    self.assert_int_type(t1.clone(), binary.left.span());
+
+                    let t2 = self.compare_expr_type(&binary.right, None, binary.right.span());
+                    self.assert_int_type(t2.clone(), binary.right.span());
+
+                    return_incorrect_type(t1, t2, expected)
+                }
+            },
+            Expression::Unary(unary) => match unary.op {
+                UnaryOperation::Not => {
+                    self.assert_type(Type::Boolean, expected.clone(), unary.span());
+                    self.compare_expr_type(&unary.inner, expected, unary.inner.span())
+                }
+                UnaryOperation::Negate => {
+                    match expected.as_ref() {
+                        Some(
+                            Type::IntegerType(
+                                IntegerType::I8
+                                | IntegerType::I16
+                                | IntegerType::I32
+                                | IntegerType::I64
+                                | IntegerType::I128,
+                            )
+                            | Type::Field
+                            | Type::Group,
+                        ) => self.negate = !self.negate,
+                        Some(t) => self
+                            .handler
+                            .emit_err(TypeCheckerError::type_is_not_negatable(t, unary.inner.span()).into()),
+                        _ => {}
+                    };
+                    self.compare_expr_type(&unary.inner, expected, unary.inner.span())
+                }
+            },
+            Expression::Ternary(ternary) => {
+                self.compare_expr_type(&ternary.condition, Some(Type::Boolean), ternary.condition.span());
+                let t1 = self.compare_expr_type(&ternary.if_true, expected.clone(), ternary.if_true.span());
+                let t2 = self.compare_expr_type(&ternary.if_false, expected.clone(), ternary.if_false.span());
+                return_incorrect_type(t1, t2, expected)
+            }
+            Expression::Call(call) => match &*call.function {
+                Expression::Identifier(ident) => {
+                    if let Some(func) = self.symbol_table.lookup_fn(&ident.name) {
+                        let ret = self.assert_type(func.output.clone(), expected, ident.span());
+
+                        if func.input.len() != call.arguments.len() {
+                            self.handler.emit_err(
+                                TypeCheckerError::incorrect_num_args_to_call(
+                                    func.input.len(),
+                                    call.arguments.len(),
+                                    call.span(),
+                                )
+                                .into(),
+                            );
+                        }
+
+                        func.input
+                            .iter()
+                            .zip(call.arguments.iter())
+                            .for_each(|(expected, argument)| {
+                                self.compare_expr_type(
+                                    argument,
+                                    Some(expected.get_variable().type_.clone()),
+                                    argument.span(),
+                                );
+                            });
+
+                        Some(ret)
+                    } else {
+                        self.handler
+                            .emit_err(TypeCheckerError::unknown_sym("function", &ident.name, ident.span()).into());
+                        None
+                    }
+                }
+                expr => self.compare_expr_type(expr, expected, call.span()),
+            },
+            Expression::Err(_) => None,
+        }
+    }
+}
+
+impl<'a> ExpressionVisitor<'a> for TypeChecker<'a> {}

compiler/passes/src/type_checker/check_file.rs

@@ -0,0 +1,42 @@
+// Copyright (C) 2019-2022 Aleo Systems Inc.
+// This file is part of the Leo library.
+
+// The Leo library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// The Leo library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with the Leo library. If not, see <https://www.gnu.org/licenses/>.
+
+use leo_ast::*;
+
+use crate::{Declaration, TypeChecker, VariableSymbol};
+
+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 input_var = i.get_variable();
+
+            if let Err(err) = self.symbol_table.insert_variable(
+                input_var.identifier.name,
+                VariableSymbol {
+                    type_: &input_var.type_,
+                    span: input_var.identifier.span(),
+                    declaration: Declaration::Input(input_var.mode()),
+                },
+            ) {
+                self.handler.emit_err(err);
+            }
+        });
+
+        VisitResult::VisitChildren
+    }
+}

compiler/passes/src/type_checker/check_statements.rs

@@ -0,0 +1,150 @@
+// Copyright (C) 2019-2022 Aleo Systems Inc.
+// This file is part of the Leo library.
+
+// The Leo library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// The Leo library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with the Leo library. If not, see <https://www.gnu.org/licenses/>.
+
+use leo_ast::*;
+use leo_errors::TypeCheckerError;
+
+use crate::{Declaration, TypeChecker, VariableSymbol};
+
+impl<'a> StatementVisitor<'a> for TypeChecker<'a> {
+    fn visit_return(&mut self, input: &'a ReturnStatement) -> VisitResult {
+        // we can safely unwrap all self.parent instances because
+        // statements should always have some parent block
+        let parent = self.parent.unwrap();
+
+        // Would never be None.
+        let func_output_type = self.symbol_table.lookup_fn(&parent).map(|f| f.output.clone());
+        self.compare_expr_type(&input.expression, func_output_type, input.expression.span());
+
+        VisitResult::VisitChildren
+    }
+
+    fn visit_definition(&mut self, input: &'a DefinitionStatement) -> VisitResult {
+        let declaration = if input.declaration_type == Declare::Const {
+            Declaration::Const
+        } else {
+            Declaration::Mut
+        };
+
+        input.variable_names.iter().for_each(|v| {
+            if let Err(err) = self.symbol_table.insert_variable(
+                v.identifier.name,
+                VariableSymbol {
+                    type_: &input.type_,
+                    span: input.span(),
+                    declaration: declaration.clone(),
+                },
+            ) {
+                self.handler.emit_err(err);
+            }
+
+            self.compare_expr_type(&input.value, Some(input.type_.clone()), input.value.span());
+        });
+
+        VisitResult::VisitChildren
+    }
+
+    fn visit_assign(&mut self, input: &'a AssignStatement) -> VisitResult {
+        let var_name = &input.assignee.identifier.name;
+        let var_type = if let Some(var) = self.symbol_table.lookup_variable(var_name) {
+            match &var.declaration {
+                Declaration::Const => self
+                    .handler
+                    .emit_err(TypeCheckerError::cannont_assign_to_const_var(var_name, var.span).into()),
+                Declaration::Input(ParamMode::Constant) => self
+                    .handler
+                    .emit_err(TypeCheckerError::cannont_assign_to_const_input(var_name, var.span).into()),
+                _ => {}
+            }
+
+            Some(var.type_.clone())
+        } else {
+            self.handler.emit_err(
+                TypeCheckerError::unknown_sym("variable", &input.assignee.identifier.name, &input.assignee.span).into(),
+            );
+
+            None
+        };
+
+        if var_type.is_some() {
+            self.compare_expr_type(&input.value, var_type, input.value.span());
+        }
+
+        VisitResult::VisitChildren
+    }
+
+    fn visit_conditional(&mut self, input: &'a ConditionalStatement) -> VisitResult {
+        self.compare_expr_type(&input.condition, Some(Type::Boolean), input.condition.span());
+
+        VisitResult::VisitChildren
+    }
+
+    fn visit_iteration(&mut self, input: &'a IterationStatement) -> VisitResult {
+        if let Err(err) = self.symbol_table.insert_variable(
+            input.variable.name,
+            VariableSymbol {
+                type_: &input.type_,
+                span: input.span(),
+                declaration: Declaration::Const,
+            },
+        ) {
+            self.handler.emit_err(err);
+        }
+
+        self.compare_expr_type(&input.start, Some(input.type_.clone()), input.start.span());
+        self.compare_expr_type(&input.stop, Some(input.type_.clone()), input.stop.span());
+
+        VisitResult::VisitChildren
+    }
+
+    fn visit_console(&mut self, input: &'a ConsoleStatement) -> VisitResult {
+        match &input.function {
+            ConsoleFunction::Assert(expr) => {
+                self.compare_expr_type(expr, Some(Type::Boolean), expr.span());
+            }
+            ConsoleFunction::Error(_) | ConsoleFunction::Log(_) => {
+                // TODO: undetermined
+            }
+        }
+
+        VisitResult::VisitChildren
+    }
+
+    fn visit_expression_statement(&mut self, input: &'a ExpressionStatement) -> VisitResult {
+        self.compare_expr_type(&input.expression, None, input.span());
+        VisitResult::SkipChildren
+    }
+
+    fn visit_block(&mut self, input: &'a Block) -> VisitResult {
+        self.symbol_table.push_variable_scope();
+        // have to redo the logic here so we have scoping
+        input.statements.iter().for_each(|stmt| {
+            match stmt {
+                Statement::Return(stmt) => self.visit_return(stmt),
+                Statement::Definition(stmt) => self.visit_definition(stmt),
+                Statement::Assign(stmt) => self.visit_assign(stmt),
+                Statement::Conditional(stmt) => self.visit_conditional(stmt),
+                Statement::Iteration(stmt) => self.visit_iteration(stmt),
+                Statement::Console(stmt) => self.visit_console(stmt),
+                Statement::Expression(stmt) => self.visit_expression_statement(stmt),
+                Statement::Block(stmt) => self.visit_block(stmt),
+            };
+        });
+        self.symbol_table.pop_variable_scope();
+
+        VisitResult::SkipChildren
+    }
+}

compiler/passes/src/type_checker/checker.rs

@@ -0,0 +1,125 @@
+// Copyright (C) 2019-2022 Aleo Systems Inc.
+// This file is part of the Leo library.
+
+// The Leo library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// The Leo library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with the Leo library. If not, see <https://www.gnu.org/licenses/>.
+
+use leo_ast::{IntegerType, Type};
+use leo_errors::{emitter::Handler, TypeCheckerError};
+use leo_span::{Span, Symbol};
+
+use crate::SymbolTable;
+
+pub struct TypeChecker<'a> {
+    pub(crate) symbol_table: &'a mut SymbolTable<'a>,
+    pub(crate) handler: &'a Handler,
+    pub(crate) parent: Option<Symbol>,
+    pub(crate) negate: bool,
+}
+
+const ARITHMETIC_TYPES: &[Type] = &[
+    Type::Field,
+    Type::Group,
+    Type::IntegerType(IntegerType::I8),
+    Type::IntegerType(IntegerType::I16),
+    Type::IntegerType(IntegerType::I32),
+    Type::IntegerType(IntegerType::I64),
+    Type::IntegerType(IntegerType::I128),
+    Type::IntegerType(IntegerType::U8),
+    Type::IntegerType(IntegerType::U16),
+    Type::IntegerType(IntegerType::U32),
+    Type::IntegerType(IntegerType::U64),
+    Type::IntegerType(IntegerType::U128),
+];
+
+const FIELD_AND_INT_TYPES: &[Type] = &[
+    Type::Field,
+    Type::IntegerType(IntegerType::I8),
+    Type::IntegerType(IntegerType::I16),
+    Type::IntegerType(IntegerType::I32),
+    Type::IntegerType(IntegerType::I64),
+    Type::IntegerType(IntegerType::I128),
+    Type::IntegerType(IntegerType::U8),
+    Type::IntegerType(IntegerType::U16),
+    Type::IntegerType(IntegerType::U32),
+    Type::IntegerType(IntegerType::U64),
+    Type::IntegerType(IntegerType::U128),
+];
+
+const INT_TYPES: &[Type] = &[
+    Type::IntegerType(IntegerType::I8),
+    Type::IntegerType(IntegerType::I16),
+    Type::IntegerType(IntegerType::I32),
+    Type::IntegerType(IntegerType::I64),
+    Type::IntegerType(IntegerType::I128),
+    Type::IntegerType(IntegerType::U8),
+    Type::IntegerType(IntegerType::U16),
+    Type::IntegerType(IntegerType::U32),
+    Type::IntegerType(IntegerType::U64),
+    Type::IntegerType(IntegerType::U128),
+];
+
+impl<'a> TypeChecker<'a> {
+    pub fn new(symbol_table: &'a mut SymbolTable<'a>, handler: &'a Handler) -> Self {
+        Self {
+            symbol_table,
+            handler,
+            parent: None,
+            negate: false,
+        }
+    }
+
+    pub(crate) fn assert_type(&self, type_: Type, expected: Option<Type>, span: &Span) -> Type {
+        if let Some(expected) = expected {
+            if type_ != expected {
+                self.handler
+                    .emit_err(TypeCheckerError::type_should_be(type_.clone(), expected, span).into());
+            }
+        }
+
+        type_
+    }
+
+    pub(crate) fn assert_one_of_types(&self, type_: Option<Type>, expected: &[Type], span: &Span) -> Option<Type> {
+        if let Some(type_) = type_.clone() {
+            for t in expected.iter() {
+                if &type_ == t {
+                    return Some(type_);
+                }
+            }
+
+            self.handler.emit_err(
+                TypeCheckerError::expected_one_type_of(
+                    expected.iter().map(|t| t.to_string() + ",").collect::<String>(),
+                    type_,
+                    span,
+                )
+                .into(),
+            );
+        }
+
+        type_
+    }
+
+    pub(crate) fn assert_arith_type(&self, type_: Option<Type>, span: &Span) -> Option<Type> {
+        self.assert_one_of_types(type_, ARITHMETIC_TYPES, span)
+    }
+
+    pub(crate) fn assert_field_or_int_type(&self, type_: Option<Type>, span: &Span) -> Option<Type> {
+        self.assert_one_of_types(type_, FIELD_AND_INT_TYPES, span)
+    }
+
+    pub(crate) fn assert_int_type(&self, type_: Option<Type>, span: &Span) -> Option<Type> {
+        self.assert_one_of_types(type_, INT_TYPES, span)
+    }
+}

compiler/passes/src/type_checker/mod.rs

@@ -0,0 +1,47 @@
+// Copyright (C) 2019-2022 Aleo Systems Inc.
+// This file is part of the Leo library.
+
+// The Leo library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// The Leo library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with the Leo library. If not, see <https://www.gnu.org/licenses/>.
+
+pub mod check_expressions;
+pub use check_expressions::*;
+
+pub mod check_file;
+pub use check_file::*;
+
+pub mod check_statements;
+pub use check_statements::*;
+
+pub mod checker;
+pub use checker::*;
+
+use crate::{Pass, SymbolTable};
+
+use leo_ast::{Ast, VisitorDirector};
+use leo_errors::{emitter::Handler, Result};
+
+impl<'a> Pass<'a> for TypeChecker<'a> {
+    type Input = (&'a Ast, &'a mut SymbolTable<'a>, &'a Handler);
+    type Output = Result<()>;
+
+    fn do_pass((ast, symbol_table, handler): Self::Input) -> Self::Output {
+        let mut visitor = VisitorDirector::new(TypeChecker::new(symbol_table, handler));
+        visitor.visit_program(ast.as_repr());
+        // todo @gluax: awkward cause last error double prints...
+        // but can't os exit or it causes tests to stop.
+        handler.last_err()?;
+
+        Ok(())
+    }
+}

disabled_tests/compiler/function/duplicate_parameter_fail.leo

@@ -1,9 +0,0 @@
-/*
-namespace: Compile
-expectation: Fail
-input_file: input/dummy.in
-*/
-
-function main(a: u32, a: u32) {
-    console.log("{}", 1u8);
-}

disabled_tests/compiler/function/multiple_returns_fail.leo

@@ -5,9 +5,6 @@ input_file: input/dummy.in
 */
 
 function main() -> i8 {
-    if true {
-        return 1i8;   //ignored
-    }
-    return 2i8;       //ignored
-    return 3i8;       //returns
+    return 2i8;
+    return 3i8;
 }

disabled_tests/compiler/function/shadow_global_const_input_fail copy.leo

@@ -1,7 +1,6 @@
 /*
 namespace: Compile
 expectation: Fail
-input_file: input/dummy.in
 */
 
 const hi = 1u32;

disabled_tests/compiler/integers/i32/max.leo

@@ -1,10 +0,0 @@
-/*
-namespace: Compile
-expectation: Pass
-input_file: ../input/dummy.in
-*/
-
-function main(y: bool) -> bool {
-    const a: i32 = 2147483647;
-    return y == true;
-}

disabled_tests/compiler/integers/i32/min.leo

@@ -1,10 +0,0 @@
-/*
-namespace: Compile
-expectation: Pass
-input_file: ../input/dummy.in
-*/
-
-function main(y: bool) -> bool {
-    const a: i32 = -2147483648;
-    return y == true;
-}

disabled_tests/compiler/integers/i32/mul.leo

@@ -1,17 +0,0 @@
-/*
-namespace: Compile
-expectation: Pass
-inputs:
- - i32.in: |
-    [main]
-    a: i32 = 2;
-    b: i32 = 5;
-    c: i32 = 10;
-    
-    [registers]
-    r0: bool = false;
-*/
-
-function main(a: i32, b: i32, c: i32) -> bool {
-    return a * b == c;
-}

disabled_tests/compiler/integers/i32/ne.leo

@@ -1,25 +0,0 @@
-/*
-namespace: Compile
-expectation: Pass
-inputs:
- - i32_ne.in: |
-    [main]
-    a: i32 = 2;
-    b: i32 = 5;
-    c: bool = true;
-
-    [registers]
-    r0: bool = false;
- - i32_e.in: |
-    [main]
-    a: i32 = 5;
-    b: i32 = 5;
-    c: bool = false;
-
-    [registers]
-    r0: bool = false;
-*/
-
-function main(a: i32, b: i32, c: bool) -> bool{
-    return (a != b) == c;
-}

disabled_tests/compiler/integers/i32/negate.leo

@@ -1,23 +0,0 @@
-/*
-namespace: Compile
-expectation: Pass
-inputs:
- - i32.in: |
-    [main]
-    a: i32 = 5;
-    b: i32 = -5;
-
-    [registers]
-    r0: bool = false;
- - i32.in: |
-    [main]
-    a: i32 = -5;
-    b: i32 = 5;
-
-    [registers]
-    r0: bool = false;
-*/
-
-function main(a: i32, b: i32) -> bool {
-    return -a == b;
-}

disabled_tests/compiler/integers/i32/negate_zero.leo

@@ -1,17 +0,0 @@
-/*
-namespace: Compile
-expectation: Pass
-inputs:
- - dummy.in: |
-    [main]
-    y: bool = true;
-
-    [registers]
-    r0: bool = false;
-*/
-
-function main(y: bool) -> bool {
-    const a = 0i32;
-
-    return (-a == 0i32) == y;
-}

disabled_tests/compiler/integers/i32/pow.leo

@@ -1,3 +0,0 @@
-function main(a: i32, b: i32, c: i32) -> bool {
-    return a ** b == c;
-}

disabled_tests/compiler/integers/i32/sub.leo

@@ -1,17 +0,0 @@
-/*
-namespace: Compile
-expectation: Pass
-inputs:
- - i32.in: |
-    [main]
-    a: i32 = 100;
-    b: i32 = 50;
-    c: i32 = 50;
-    
-    [registers]
-    r0: bool = false;
-*/
-
-function main(a: i32, b: i32, c: i32) -> bool {
-    return a - b == c;
-}

disabled_tests/compiler/integers/i32/ternary.leo

@@ -1,29 +0,0 @@
-/*
-namespace: Compile
-expectation: Pass
-inputs:
- - i32.in: |
-    [main]
-    s: bool = true;
-    a: i32 = 10;
-    b: i32 = 5;
-    c: i32 = 10;
-
-    [registers]
-    r0: bool = false;
- - i32_rev.in: |
-    [main]
-    s: bool = false;
-    a: i32 = 10;
-    b: i32 = 5;
-    c: i32 = 5;
-
-    [registers]
-    r0: bool = false;
-*/
-
-function main(s: bool, a: i32, b: i32, c: i32) -> bool {
-    let r = s ? a : b;
-
-    return r == c;
-}

disabled_tests/compiler/integers/i8/negate_min.leo

@@ -1,9 +1,12 @@
 /*
 namespace: Compile
-expectation: Fail
+expectation: Pass
+input_file: ../input/dummy.in
 */
 
-function main() {
-    const a = -128i8;
-    const b = -a;
+function main(y: bool) -> bool {
+    const a: = -128i8;
+    const b: = -a;
+
+    return (b == -a) == y;
 }

disabled_tests/compiler/mutability/let_mut_nested.leo

@@ -1,12 +0,0 @@
-/*
-namespace: Compile
-expectation: Pass
-input_file: input/dummy.in
-*/
-
-function main(a: bool) -> bool {
-    let x = 2u8;
-    let y = x;
-    let z = y / 2u8;
-    return (z == 1) == a;
-}

disabled_tests/compiler/statements/all_loops.leo

@@ -1,29 +0,0 @@
-/*
-namespace: Compile
-expectation: Pass
-input_file: inputs/dummy.in
-*/
-
-function main(k: bool) -> bool {
-    let reverse: u32 = 0;
-    for i in 9..0 {
-        reverse += i;
-    }
-
-    let forward: u32 = 0;
-    for x in 0..10 {
-        forward += x;
-    }
-
-    let reverse_inclusive: u32 = 0;
-    for a in 10..=0 {
-        reverse_inclusive += a;
-    }
-
-    let forward_inclusive: u32 = 0;
-    for b in 0..=10 {
-        forward_inclusive += b;
-    }
-
-    return (reverse == forward) && (reverse_inclusive == forward_inclusive) && k;
-}

disabled_tests/compiler/statements/iteration_variable.leo

@@ -1,16 +0,0 @@
-/*
-namespace: Compile
-expectation: Pass
-input_file: inputs/u32_3.in
-*/
-
-function main(x: u32) -> bool {
-    const COUNT: u32 = 2;
-    let y = x;
-    
-    for i in 0..COUNT {
-        y -= 1;
-    }
-
-    return y == 1;
-}

leo/errors/src/errors/ast/ast_errors.rs

@@ -147,14 +147,6 @@ create_messages!(
         help: None,
     }
 
-    /// For when a user shadows a function input.
-    @formatted
-    shadowed_function_input {
-        args: (fn_input: impl Display),
-        msg: format!("function input `{fn_input}` shadowed"),
-        help: None,
-    }
-
     /// For when a user shadows a variable.
     @formatted
     shadowed_variable {

leo/errors/src/errors/input/input_errors.rs

@@ -20,7 +20,7 @@ use std::fmt::{Debug, Display};
 create_messages!(
     /// InputError enum that represents all the errors for the inputs part of `leo-ast` crate.
     InputError,
-    code_mask: 8000i32,
+    code_mask: 1000i32,
     code_prefix: "INP",
 
     /// For when declared variable type mismatches actual type.

leo/errors/src/errors/mod.rs

@@ -41,6 +41,10 @@ pub use self::package::*;
 pub mod parser;
 pub use self::parser::*;
 
+/// Contains the Type Checker error definitions.
+pub mod type_checker;
+pub use self::type_checker::*;
+
 /// The LeoError type that contains all sub error types.
 /// This allows a unified error type throughout the Leo crates.
 #[derive(Clone, Debug, Error)]
@@ -63,6 +67,9 @@ pub enum LeoError {
     /// Represents an Parser Error in a Leo Error.
     #[error(transparent)]
     ParserError(#[from] ParserError),
+    /// Represents an Type Checker Error in a Leo Error.
+    #[error(transparent)]
+    TypeCheckerError(#[from] TypeCheckerError),
 }
 
 impl LeoError {
@@ -77,6 +84,7 @@ impl LeoError {
             InputError(error) => error.error_code(),
             ParserError(error) => error.error_code(),
             PackageError(error) => error.error_code(),
+            TypeCheckerError(error) => error.error_code(),
         }
     }
 
@@ -91,6 +99,7 @@ impl LeoError {
             InputError(error) => error.exit_code(),
             ParserError(error) => error.exit_code(),
             PackageError(error) => error.exit_code(),
+            TypeCheckerError(error) => error.exit_code(),
         }
     }
 }

leo/errors/src/errors/type_checker/mod.rs

@@ -0,0 +1,19 @@
+// Copyright (C) 2019-2022 Aleo Systems Inc.
+// This file is part of the Leo library.
+
+// The Leo library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// The Leo library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with the Leo library. If not, see <https://www.gnu.org/licenses/>.
+
+/// This module contains the Input error definitions.
+pub mod type_checker_error;
+pub use self::type_checker_error::*;

leo/errors/src/errors/type_checker/type_checker_error.rs

@@ -0,0 +1,135 @@
+// Copyright (C) 2019-2022 Aleo Systems Inc.
+// This file is part of the Leo library.
+
+// The Leo library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// The Leo library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with the Leo library. If not, see <https://www.gnu.org/licenses/>.
+
+use crate::create_messages;
+use std::fmt::{Debug, Display};
+
+create_messages!(
+    /// InputError enum that represents all the errors for the inputs part of `leo-ast` crate.
+    TypeCheckerError,
+    code_mask: 2000i32,
+    code_prefix: "TYC",
+
+    /// For when the user tries to assign to a const input.
+    @formatted
+    cannont_assign_to_const_input {
+        args: (input: impl Display),
+        msg: format!(
+            "Cannot assign to const input `{input}`",
+        ),
+        help: None,
+    }
+
+    /// For when the user tries to assign to a const input.
+    @formatted
+    cannont_assign_to_const_var {
+        args: (var: impl Display),
+        msg: format!(
+            "Cannot assign to const variable `{var}`",
+        ),
+        help: None,
+    }
+
+    /// For when the user tries to assign to a const input.
+    @formatted
+    type_should_be {
+        args: (type_: impl Display, expected: impl Display),
+        msg: format!(
+            "Found type `{type_}` but type `{expected}` was expected",
+        ),
+        help: None,
+    }
+
+    /// For when the user tries to return a unknown variable.
+    @formatted
+    unknown_sym {
+        args: (kind: impl Display, sym: impl Display),
+        msg: format!(
+            "Unknown {kind} `{sym}`",
+        ),
+        help: None,
+    }
+
+    /// For when the user tries to expect a non integer type .
+    @formatted
+    type_should_be_integer {
+        args: (op: impl Debug, type_: impl Display),
+        msg: format!(
+            "Binary statement has numeric operation `{op:?}` but has expected type `{type_}`",
+        ),
+        help: None,
+    }
+
+    /// For when the user tries to negate a non negatable type.
+    @formatted
+    type_is_not_negatable {
+        args: (type_: impl Display),
+        msg: format!(
+            "The type `{type_}` is not negatable",
+        ),
+        help: None,
+    }
+
+    /// For when the user tries calls a function with the incorrect number of args.
+    @formatted
+    incorrect_num_args_to_call {
+        args: (expected: impl Display, received: impl Display),
+        msg: format!(
+            "Call expected `{expected}` args, but got `{received}`",
+        ),
+        help: None,
+    }
+
+    /// For when one of the following types was expected.
+    @formatted
+    expected_one_type_of {
+        args: (expected: impl Display, received: impl Display),
+        msg: format!(
+            "Expected one type from `{expected}`, but got `{received}`",
+        ),
+        help: None,
+    }
+
+    /// For when the base of a power is not a valid type.
+    @formatted
+    incorrect_pow_base_type {
+        args: (type_: impl Display),
+        msg: format!(
+            "The first operand must be an integer or field but got type `{type_}`",
+        ),
+        help: None,
+    }
+
+    /// For when the exponent of a power is not a valid type.
+    @formatted
+    incorrect_pow_exponent_type {
+        args: (allowed: impl Display, type_: impl Display),
+        msg: format!(
+            "The second operand must be a {allowed} but got type `{type_}`",
+        ),
+        help: None,
+    }
+
+    /// For when an integer is not in a valid range.
+    @formatted
+    invalid_int_value {
+        args: (value: impl Display, type_: impl Display),
+        msg: format!(
+            "The value {value} is not a valid `{type_}`",
+        ),
+        help: None,
+    }
+);

tests/compiler/_group/add.leo

@@ -1,3 +0,0 @@
-function main(a: group, b: group, c: group) {
-    console.assert(a + b == c);
-}

tests/compiler/_group/assert_eq.leo

@@ -1,3 +0,0 @@
-function main(a: group, b: group) {
-    console.assert(a == b);
-}

tests/compiler/_group/both_sign_high.leo

@@ -1,3 +0,0 @@
-function main() {
-    const element = (+, +)group;
-}

tests/compiler/_group/both_sign_inferred.leo

@@ -1,3 +0,0 @@
-function main() {
-    const element = (_, _)group;
-}

tests/compiler/_group/both_sign_low.leo

@@ -1,3 +0,0 @@
-function main() {
-    const element = (-, -)group;
-}

tests/compiler/_group/eq.leo

@@ -1,3 +0,0 @@
-function main(a: group, b: group, c: bool) {
-    console.assert((a == b) == c);
-}

tests/compiler/_group/input.leo

@@ -1,3 +0,0 @@
-function main(a: group, b: group) {
-    console.assert(a == b);
-}

tests/compiler/_group/input/valid.in

@@ -1,3 +0,0 @@
-[main]
-a: group = (0, -)group;
-b: group = (0, _)group;

tests/compiler/_group/negate.leo

@@ -1,3 +0,0 @@
-function main(a: group, b: group) {
-    console.assert(-a == b);
-}

tests/compiler/_group/no_space_between_literal.leo

@@ -1,3 +0,0 @@
-function main() {
-  const g = (0,1) group;
-}

tests/compiler/_group/one.leo

@@ -1,3 +0,0 @@
-function main() {
-    const element = 1group;
-}

tests/compiler/_group/point.leo

@@ -1,3 +0,0 @@
-function main() {
-    const point = (7374112779530666882856915975292384652154477718021969292781165691637980424078, 3435195339177955418892975564890903138308061187980579490487898366607011481796)group;
-}

tests/compiler/_group/point_input.leo

@@ -1,3 +0,0 @@
-function main(a: group) {
-    const b = a;
-}

tests/compiler/_group/positive_and_negative.leo

@@ -1,10 +0,0 @@
-function main() {
-    const pos_element = 1group;
-    const neg_element = -1group;
-
-    const pair_x_pos = (1, _)group;
-    const pair_x_neg = (-1, _)group;
-
-    const pair_y_pos = (_, 1)group;
-    const pair_y_neg = (_, -1)group;
-}

tests/compiler/_group/sub.leo

@@ -1,3 +0,0 @@
-function main(a: group, b: group, c: group) {
-    console.assert(a - b == c);
-}

tests/compiler/_group/ternary.leo

@@ -1,5 +0,0 @@
-function main(s: bool, a: group, b: group, c: group) {
-    const r = s ? a : b;
-
-    console.assert(r == c);
-}

tests/compiler/_group/x_sign_high.leo

@@ -1,3 +0,0 @@
-function main() {
-    const element = (0, +)group;
-}

tests/compiler/_group/x_sign_inferred.leo

@@ -1,3 +0,0 @@
-function main() {
-    const element = (0, _)group;
-}

tests/compiler/_group/x_sign_low.leo

@@ -1,3 +0,0 @@
-function main() {
-    const element = (0, -)group;
-}

tests/compiler/_group/y_sign_high.leo

@@ -1,3 +0,0 @@
-function main() {
-    const element = (+, 1)group;
-}

tests/compiler/_group/y_sign_inferred.leo

@@ -1,3 +0,0 @@
-function main() {
-    const element = (_, 1)group;
-}

tests/compiler/_group/y_sign_low.leo

@@ -1,3 +0,0 @@
-function main() {
-    const element = (-, 1)group;
-}

tests/compiler/_group/zero.leo

@@ -1,3 +0,0 @@
-function main() {
-    const element = 0group;
-}

tests/compiler/boolean/and.leo

@@ -2,10 +2,10 @@
 namespace: Compile
 expectation: Pass
 input_file:
- - input/false_false.in
- - input/false_true.in
- - input/true_false.in
- - input/true_true.in
+ - inputs/false_false.in
+ - inputs/false_true.in
+ - inputs/true_false.in
+ - inputs/true_true.in
 */
 
 function main(a: bool, b: bool) -> bool {

tests/compiler/boolean/conditional.leo

@@ -2,10 +2,10 @@
 namespace: Compile
 expectation: Pass
 input_file:
- - input/false_false.in
- - input/false_true.in
- - input/true_false.in
- - input/true_true.in
+ - inputs/false_false.in
+ - inputs/false_true.in
+ - inputs/true_false.in
+ - inputs/true_true.in
 */
 
 function main(a: bool, b: bool) -> bool {

tests/compiler/boolean/equal.leo

@@ -2,10 +2,10 @@
 namespace: Compile
 expectation: Pass
 input_file:
- - input/false_false.in
- - input/false_true.in
- - input/true_false.in
- - input/true_true.in
+ - inputs/false_false.in
+ - inputs/false_true.in
+ - inputs/true_false.in
+ - inputs/true_true.in
 */
 
 function main(a: bool, b: bool) -> bool {

tests/compiler/boolean/not_equal.leo

@@ -2,10 +2,10 @@
 namespace: Compile
 expectation: Pass
 input_file:
- - input/false_false.in
- - input/false_true.in
- - input/true_false.in
- - input/true_true.in
+ - inputs/false_false.in
+ - inputs/false_true.in
+ - inputs/true_false.in
+ - inputs/true_true.in
 */
 
 function main(a: bool, b: bool) -> bool {

tests/compiler/boolean/or.leo

@@ -2,10 +2,10 @@
 namespace: Compile
 expectation: Pass
 input_file:
- - input/false_false.in
- - input/false_true.in
- - input/true_false.in
- - input/true_true.in
+ - inputs/false_false.in
+ - inputs/false_true.in
+ - inputs/true_false.in
+ - inputs/true_true.in
 */
 
 function main(a: bool, b: bool) -> bool {

tests/compiler/console/assert.leo

@@ -1,13 +1,7 @@
 /*
 namespace: Compile
 expectation: Pass
-inputs:
- - assert.in: |
-    [main]
-    a: bool = true;
-
-    [registers]
-    r0: bool = false;
+input_file: inputs/true.in
 */
 
 function main(a: bool) -> bool {