Resolve merge conflict

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,3 @@
+## 👉 [Please follow one of these issue templates](https://github.com/AleoHQ/leo/issues/new/choose) 👈
+
+Note: to keep the backlog clean and actionable, issues may be immediately closed if they do not follow one of the above issue templates.

.github/ISSUE_TEMPLATE/01_bug_report.md

@@ -1,38 +0,0 @@
----
-name: "\U0001F41B Bug report"
-about: Create a bug report if something isn't working 🔧
-title: "[Bug]"
-labels: bug
-assignees: ''
----
-
-## 🐛 Describe the Bug
-
-<!-- A clear and concise description of what the bug is. -->
-<!-- To report a security issue, please email security@aleo.org. -->
-
-## Steps to Reproduce
-
-#### Code snippet to reproduce
-
-```rust
-# Add code here
-```
-
-#### Stack trace & error message
-
-```
-// Paste the output here
-```
-
-## Expected Behavior
-
-<!-- A clear and concise description of what you expected to happen. -->
-
-## System information
-
-- <!-- Leo Version -->
-
-- <!-- Rust Version -->
-
-- <!-- Computer OS -->

.github/ISSUE_TEMPLATE/02_bug_report.md

@@ -1,34 +0,0 @@
----
-name: "\U0001F680 Feature request"
-about: Submit a new feature request 💡
-title: "[Feature]"
-labels: feature
-assignees: ''
----
-
-## 🚀 Describe the Feature
-
-<!-- A clear and concise description of the feature you are requesting -->
-
-## Motivation
-
-**Is the feature request related to a problem? If so, please describe.**
-
-<!-- A clear and concise description of what the problem is.
-     Please link to any relevant issues or other PRs! -->
-
-**Is this something that currently cannot be done?**
-
-## Solution
-
-<!-- A clear and concise description of what you want to happen. -->
-
-**Are you willing to open a pull request?** (See [CONTRIBUTING](../../CONTRIBUTING.md))
-
-## Alternative Solutions
-
-<!-- A clear and concise description of any alternative solutions or features you've considered. -->
-
-## Relevant Context
-
-<!-- Add any other context or screenshots about the feature request here. -->

.github/ISSUE_TEMPLATE/bug.md

@@ -0,0 +1,52 @@
+---
+name: 🐛 Bug Report
+about: Submit a bug report if something isn't working
+title: "[Bug]"
+labels: bug
+---
+
+## 🐛 Bug Report
+
+<!--
+    What's the bug in Leo that you found?
+    How serious is this bug and what is affected?
+    
+    To report a security issue in Leo, please email security@aleo.org.
+-->
+
+(Write your description here)
+
+## Steps to Reproduce
+
+<!--
+    How do I reproduce this issue in Leo?
+    Is there a code snippet I can use to reproduce the issue?
+    Are there error messages or stack traces that would help debug this issue?
+-->
+
+#### Code snippet to reproduce
+
+```
+# Add code here
+```
+
+#### Stack trace & error message
+
+```
+// Paste the output here
+```
+
+## Expected Behavior
+
+<!--
+    What was supposed to happen in Leo?
+    What happened instead?
+-->
+
+(Write what you expected to happen here)
+
+## Your Environment
+
+- <!-- Leo Version -->
+- <!-- Rust Version -->
+- <!-- Computer OS -->

.github/ISSUE_TEMPLATE/config.yml

@@ -1,5 +1,5 @@
 blank_issues_enabled: true
 contact_links:
-  - name: ❓ Help and Support Discord Channel
+  - name: ❓ Q&A Technical Support Channel
     url: https://discord.gg/dTw3wk9
-    about: Please ask and answer questions here. 🏥
+    about: For quick questions or technical troubleshooting, please ask them on our dedicated Discord channel.

.github/ISSUE_TEMPLATE/documentation.md

@@ -0,0 +1,15 @@
+---
+name: 📚 Documentation
+about: Report an issue related to documentation
+title: "[Docs]"
+labels: 'documentation'
+---
+
+## 📚 Documentation
+
+<!--
+    Did you find a mistake in the Leo documentation?
+    Is there documentation about Leo that's missing?
+-->
+
+(Write your answer here.)

.github/ISSUE_TEMPLATE/feature.md

@@ -0,0 +1,36 @@
+---
+name:  🚀 Feature
+about: Submit a new feature request
+title: "[Feature]"
+labels: feature
+---
+
+## 🚀 Feature
+
+<!--
+    What is the feature you would like to see in Leo?
+-->
+
+(Write your description here)
+
+## Motivation
+
+<!--
+    Why should this feature be implemented in Leo?
+    How would this feature be used in Leo?
+    
+    Is this feature request related to a problem? If so, please describe.
+    Please link to any relevant issues or other PRs!
+-->
+
+(Outline your motivation here)
+
+## Implementation
+
+<!--
+    What needs to be built for the feature to be supported in Leo?
+    What components of Leo will be affected by this design (if any)?
+    How should this feature be implemented?
+-->
+
+**Are you willing to open a pull request?** (See [CONTRIBUTING](../../CONTRIBUTING.md))

.github/ISSUE_TEMPLATE/proposal.md

@@ -0,0 +1,16 @@
+---
+name: 💥 Proposal
+about: Propose a non-trivial change to Leo
+title: "[Proposal]"
+labels: 'proposal'
+---
+
+## 💥 Proposal
+
+<!--
+    What is your proposal for Leo?
+    What are the implications of this proposal to Leo?
+    Does your proposal affect other aspects of Aleo as well?
+-->
+
+(Write your proposal here)

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,31 @@
+<!--
+    Thank you for submitting the PR! We appreciate you spending the time to work on these changes.
+
+    Help us understand your motivation by explaining why you decided to make this change.
+
+    Happy contributing!
+-->
+
+## Motivation
+
+(Write your motivation here)
+
+## Test Plan
+
+<!--
+    If you changed any code,
+    please provide us with clear instructions on how you verified your changes work.
+    Bonus points for screenshots and videos!
+-->
+
+(Write your test plan here)
+
+## Related PRs
+
+<!--
+    If this PR adds or changes functionality,
+    please take some time to update the docs at https://github.com/AleoHQ/leo,
+    and link to your PR here.
+-->
+
+(Link your related PRs here)

.github/workflows/ci.yml

@@ -42,8 +42,8 @@ jobs:
   test:
     name: Test
     runs-on: ubuntu-latest
-    env:
-      RUSTFLAGS: -Dwarnings
+#    env:
+#      RUSTFLAGS: -Dwarnings
     strategy:
       matrix:
         rust:
@@ -68,27 +68,27 @@ jobs:
           toolchain: ${{ matrix.rust }}
           override: true
 
-      - name: Check examples
-        uses: actions-rs/cargo@v1
-        env:
-          CARGO_NET_GIT_FETCH_WITH_CLI: true
-        with:
-          command: check
-          args: --examples --all
-
-      - name: Check examples with all features on stable
-        uses: actions-rs/cargo@v1
-        with:
-          command: check
-          args: --examples --all-features --all
-        if: matrix.rust == 'stable'
-
-      - name: Check benchmarks on nightly
-        uses: actions-rs/cargo@v1
-        with:
-          command: check
-          args: --all-features --examples --all --benches
-        if: matrix.rust == 'nightly'
+#      - name: Check examples
+#        uses: actions-rs/cargo@v1
+#        env:
+#          CARGO_NET_GIT_FETCH_WITH_CLI: true
+#        with:
+#          command: check
+#          args: --examples --all
+#
+#      - name: Check examples with all features on stable
+#        uses: actions-rs/cargo@v1
+#        with:
+#          command: check
+#          args: --examples --all-features --all
+#        if: matrix.rust == 'stable'
+#
+#      - name: Check benchmarks on nightly
+#        uses: actions-rs/cargo@v1
+#        with:
+#          command: check
+#          args: --all-features --examples --all --benches
+#        if: matrix.rust == 'nightly'
 
       - name: Test
         uses: actions-rs/cargo@v1

Cargo.lock

@@ -649,6 +649,10 @@ dependencies = [
  "thiserror",
 ]
 
+[[package]]
+name = "leo-linter"
+version = "0.1.0"
+
 [[package]]
 name = "leo-types"
 version = "0.1.0"
@@ -657,6 +661,7 @@ dependencies = [
  "leo-input",
  "pest",
  "serde",
+ "serde_json",
  "snarkos-errors",
  "snarkos-models",
 ]

Cargo.toml

@@ -13,7 +13,7 @@ name = "leo"
 path = "leo/main.rs"
 
 [workspace]
-members = [ "ast", "compiler", "gadgets", "leo-input", "types" ]
+members = [ "ast", "compiler", "gadgets", "leo-input", "linter", "types" ]
 
 [dependencies]
 leo-compiler = { path = "compiler", version = "0.1.0" }

ast/Cargo.toml

@@ -18,3 +18,5 @@ pest_derive = { version = "2.0" }
 serde = { version = "1.0", features = ["derive"] }
 serde_json = { version = "1.0" }
 thiserror = { version = "1.0" }
+
+[dev-dependencies]

ast/src/lib.rs

@@ -29,29 +29,41 @@ pub(crate) use span::*;
 use from_pest::FromPest;
 use std::{fs, path::PathBuf};
 
-pub struct LeoParser;
+pub struct LeoAst<'ast> {
+    ast: files::File<'ast>,
+}
 
-impl LeoParser {
+impl<'ast> LeoAst<'ast> {
+    /// Creates a new abstract syntax tree given the file path.
+    pub fn new(file_path: &'ast PathBuf, program_string: &'ast str) -> Result<Self, ParserError> {
+        // TODO (howardwu): Turn this check back on after fixing the testing module.
+        // assert_eq!(program_string, fs::read_to_string(file_path).map_err(|_| ParserError::FileReadError(file_path.clone()))?);
+
+        // Parse the file using leo.pest
+        let file = &mut ast::parse(&program_string)
+            .map_err(|error| ParserError::from(error.with_path(file_path.to_str().unwrap())))?;
+
+        // Builds the abstract syntax tree using pest derivation.
+        let ast = files::File::<'ast>::from_pest(file).map_err(|_| ParserError::SyntaxTreeError)?;
+        log::debug!("{:#?}", ast);
+
+        Ok(Self { ast })
+    }
+
+    // TODO (howardwu): Remove this in favor of a dedicated file loader to verify checksums
+    //  and maintain a global cache of program strings during the compilation process.
     /// Loads the Leo code as a string from the given file path.
-    pub fn load_file(file_path: &PathBuf) -> Result<String, ParserError> {
+    pub fn load_file(file_path: &'ast PathBuf) -> Result<String, ParserError> {
         Ok(fs::read_to_string(file_path).map_err(|_| ParserError::FileReadError(file_path.clone()))?)
     }
 
-    /// Parses the Leo program string and constructs an abstract syntax tree.
-    pub fn parse_file<'a>(file_path: &'a PathBuf, program_string: &'a str) -> Result<files::File<'a>, ParserError> {
-        // Parse the file using leo.pest
-        let mut file = ast::parse(program_string)
-            .map_err(|error| ParserError::from(error.with_path(file_path.to_str().unwrap())))?;
-
-        // Build the abstract syntax tree
-        let syntax_tree = files::File::from_pest(&mut file).map_err(|_| ParserError::SyntaxTreeError)?;
-        log::debug!("{:#?}", syntax_tree);
-
-        Ok(syntax_tree)
+    /// Returns a reference to the inner abstract syntax tree representation.
+    pub fn as_repr(&self) -> &files::File<'ast> {
+        &self.ast
     }
 
-    /// Serializes a given abstract syntax tree into a JSON string.
-    pub fn to_json_string(syntax_tree: &files::File) -> Result<String, ParserError> {
-        Ok(serde_json::to_string_pretty(syntax_tree)?)
+    /// Serializes the abstract syntax tree into a JSON string.
+    pub fn to_json_string(&self) -> Result<String, ParserError> {
+        Ok(serde_json::to_string_pretty(&self.ast)?)
     }
 }

ast/src/main.rs

@@ -1,16 +1,16 @@
-use leo_ast::{LeoParser, ParserError};
+use leo_ast::{LeoAst, ParserError};
 use std::{env, fs, path::Path};
 
 fn to_leo_ast(filepath: &Path) -> Result<String, ParserError> {
     // Loads the Leo code as a string from the given file path.
     let program_filepath = filepath.to_path_buf();
-    let program_string = LeoParser::load_file(&program_filepath)?;
+    let program_string = LeoAst::load_file(&program_filepath)?;
 
-    // Parses the Leo program string and constructs an abstract syntax tree.
-    let abstract_syntax_tree = LeoParser::parse_file(&program_filepath, &program_string)?;
+    // Parses the Leo file and constructs an abstract syntax tree.
+    let ast = LeoAst::new(&program_filepath, &program_string)?;
 
     // Serializes the abstract syntax tree into JSON format.
-    let serialized_ast = LeoParser::to_json_string(&abstract_syntax_tree)?;
+    let serialized_ast = LeoAst::to_json_string(&ast)?;
 
     Ok(serialized_ast)
 }

ast/tests/mod.rs

@@ -0,0 +1 @@
+mod serialization;

ast/tests/serialization/expected_ast.json

@@ -0,0 +1,91 @@
+{
+  "imports": [],
+  "circuits": [],
+  "functions": [
+    {
+      "function_name": {
+        "value": "main",
+        "span": {
+          "input": "main",
+          "start": 9,
+          "end": 13
+        }
+      },
+      "parameters": [],
+      "returns": [],
+      "statements": [
+        {
+          "Return": {
+            "return_": {
+              "Single": {
+                "Binary": {
+                  "operation": "Add",
+                  "left": {
+                    "Value": {
+                      "Implicit": {
+                        "number": {
+                          "value": "1",
+                          "span": {
+                            "input": "1",
+                            "start": 29,
+                            "end": 30
+                          }
+                        },
+                        "span": {
+                          "input": "1",
+                          "start": 29,
+                          "end": 30
+                        }
+                      }
+                    }
+                  },
+                  "right": {
+                    "Value": {
+                      "Implicit": {
+                        "number": {
+                          "value": "1",
+                          "span": {
+                            "input": "1",
+                            "start": 33,
+                            "end": 34
+                          }
+                        },
+                        "span": {
+                          "input": "1",
+                          "start": 33,
+                          "end": 34
+                        }
+                      }
+                    }
+                  },
+                  "span": {
+                    "input": "1 + 1",
+                    "start": 29,
+                    "end": 34
+                  }
+                }
+              }
+            },
+            "span": {
+              "input": "return 1 + 1",
+              "start": 22,
+              "end": 34
+            }
+          }
+        }
+      ],
+      "span": {
+        "input": "function main() {\n    return 1 + 1\n}\n",
+        "start": 0,
+        "end": 37
+      }
+    }
+  ],
+  "tests": [],
+  "eoi": null,
+  "span": {
+    "input": "function main() {\n    return 1 + 1\n}\n",
+    "start": 0,
+    "end": 37
+  }
+}

ast/tests/serialization/json.rs

@@ -0,0 +1,22 @@
+use leo_ast::LeoAst;
+
+use std::path::PathBuf;
+
+#[test]
+fn test_serialization() {
+    let mut program_filepath = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
+    program_filepath.push("tests/serialization/main.leo");
+
+    let expected = include_str!("./expected_ast.json");
+
+    // Loads the Leo code as a string from the given file path.
+    let program_string = LeoAst::load_file(&program_filepath).unwrap();
+
+    // Parses the Leo file and constructs an abstract syntax tree.
+    let ast = LeoAst::new(&program_filepath, &program_string).unwrap();
+
+    // Serializes the abstract syntax tree into JSON format.
+    let serialized_ast = LeoAst::to_json_string(&ast).unwrap();
+
+    assert_eq!(expected, serialized_ast);
+}

ast/tests/serialization/main.leo

@@ -0,0 +1,3 @@
+function main() {
+    return 1 + 1
+}

ast/tests/serialization/mod.rs

@@ -0,0 +1 @@
+mod json;

compiler/src/compiler.rs

@@ -8,9 +8,9 @@ use crate::{
     OutputBytes,
     OutputFile,
 };
-use leo_ast::LeoParser;
+use leo_ast::LeoAst;
 use leo_input::LeoInputParser;
-use leo_types::{Input, MainInput, Program};
+use leo_types::{Input, LeoTypedAst, MainInput, Program};
 
 use snarkos_errors::gadgets::SynthesisError;
 use snarkos_models::{
@@ -47,6 +47,18 @@ impl<F: Field + PrimeField, G: GroupType<F>> Compiler<F, G> {
         }
     }
 
+    /// Parse the input and state files.
+    /// Stores a typed ast of all input variables to the program.
+    pub fn parse_input(&mut self, input_string: &str, state_string: &str) -> Result<(), CompilerError> {
+        let input_syntax_tree = LeoInputParser::parse_file(&input_string)?;
+        let state_syntax_tree = LeoInputParser::parse_file(&state_string)?;
+
+        self.program_input.parse_input(input_syntax_tree)?;
+        self.program_input.parse_state(state_syntax_tree)?;
+
+        Ok(())
+    }
+
     /// Parses program files.
     /// Returns a compiler struct that stores the typed program abstract syntax trees (ast).
     pub fn parse_program_without_input(
@@ -56,8 +68,7 @@ impl<F: Field + PrimeField, G: GroupType<F>> Compiler<F, G> {
     ) -> Result<Self, CompilerError> {
         let mut compiler = Self::new(package_name, main_file_path, output_directory);
 
-        let program_string = compiler.load_program()?;
-        compiler.parse_program(&program_string)?;
+        compiler.parse_program()?;
 
         Ok(compiler)
     }
@@ -74,34 +85,33 @@ impl<F: Field + PrimeField, G: GroupType<F>> Compiler<F, G> {
         let mut compiler = Self::new(package_name, main_file_path, output_directory);
 
         compiler.parse_input(input_string, state_string)?;
-
-        let program_string = compiler.load_program()?;
-        compiler.parse_program(&program_string)?;
+        compiler.parse_program()?;
 
         Ok(compiler)
     }
 
-    /// Parse the input and state files.
-    /// Stores a typed ast of all input variables to the program.
-    pub fn parse_input(&mut self, input_string: &str, state_string: &str) -> Result<(), CompilerError> {
-        let input_syntax_tree = LeoInputParser::parse_file(&input_string)?;
-        let state_syntax_tree = LeoInputParser::parse_file(&state_string)?;
+    /// Parses the Leo program file, constructs a syntax tree, and generates a program.
+    pub(crate) fn parse_program(&mut self) -> Result<(), CompilerError> {
+        // Use the parser to construct the abstract syntax tree.
+        let program_string = LeoAst::load_file(&self.main_file_path)?;
 
-        self.program_input.parse_input(input_syntax_tree)?;
-        self.program_input.parse_state(state_syntax_tree)?;
-
-        Ok(())
+        self.parse_program_from_string(&program_string)
     }
 
-    /// Parse the program file and all associated import files.
-    pub fn parse_program(&mut self, program_string: &str) -> Result<(), CompilerError> {
-        // Parse the program syntax tree
-        let syntax_tree = LeoParser::parse_file(&self.main_file_path, program_string)?;
+    /// Parses the Leo program string, constructs a syntax tree, and generates a program.
+    /// Used for testing only.
+    #[deprecated(note = "Please use the 'parse_program' method instead.")]
+    pub fn parse_program_from_string(&mut self, program_string: &str) -> Result<(), CompilerError> {
+        // Use the given bytes to construct the abstract syntax tree.
+        let ast = LeoAst::new(&self.main_file_path, &program_string)?;
 
-        // Build program from syntax tree
+        // Derive the package name.
         let package_name = self.package_name.clone();
 
-        self.program = Program::from(syntax_tree, package_name);
+        // Use the typed parser to construct the typed syntax tree.
+        let typed_tree = LeoTypedAst::new(&package_name, &ast);
+
+        self.program = typed_tree.into_repr();
         self.imported_programs = ImportParser::parse(&self.program)?;
 
         log::debug!("Program parsing complete\n{:#?}", self.program);
@@ -109,11 +119,6 @@ impl<F: Field + PrimeField, G: GroupType<F>> Compiler<F, G> {
         Ok(())
     }
 
-    /// Loads the program file at `main_file_path`.
-    fn load_program(&mut self) -> Result<String, CompilerError> {
-        Ok(LeoParser::load_file(&self.main_file_path)?)
-    }
-
     /// Manually sets main function input
     pub fn set_main_input(&mut self, input: MainInput) {
         self.program_input.set_main_input(input);
@@ -158,7 +163,6 @@ impl<F: Field + PrimeField, G: GroupType<F>> Compiler<F, G> {
         generate_constraints::<_, G, _>(cs, self.program, self.program_input, &self.imported_programs).map_err(
             |mut error| {
                 error.set_path(path);
-
                 error
             },
         )

compiler/src/import/parser/parse_symbol.rs

@@ -1,5 +1,5 @@
 use crate::{errors::ImportError, ImportParser};
-use leo_ast::LeoParser;
+use leo_ast::LeoAst;
 use leo_types::{ImportSymbol, Program, Span};
 
 use std::{ffi::OsString, fs::DirEntry, path::PathBuf};
@@ -30,12 +30,12 @@ fn parse_import_file(entry: &DirEntry, span: &Span) -> Result<Program, ImportErr
         }
     }
 
-    // Build the abstract syntax tree
-    let input_file = &LeoParser::load_file(&file_path)?;
-    let syntax_tree = LeoParser::parse_file(&file_path, input_file)?;
+    // Builds the abstract syntax tree.
+    let program_string = &LeoAst::load_file(&file_path)?;
+    let ast = &LeoAst::new(&file_path, &program_string)?;
 
-    // Generate aleo program from file
-    Ok(Program::from(syntax_tree, file_name.clone()))
+    // Generates the Leo program from file.
+    Ok(Program::from(&file_name, ast.as_repr()))
 }
 
 impl ImportParser {

compiler/tests/mod.rs

@@ -45,7 +45,7 @@ pub(crate) fn parse_program(bytes: &[u8]) -> Result<EdwardsTestCompiler, Compile
     let mut compiler = new_compiler();
     let program_string = String::from_utf8_lossy(bytes);
 
-    compiler.parse_program(&program_string)?;
+    compiler.parse_program_from_string(&program_string)?;
 
     Ok(compiler)
 }
@@ -90,8 +90,8 @@ pub fn parse_program_with_input(
     let program_string = String::from_utf8_lossy(program_bytes);
     let input_string = String::from_utf8_lossy(input_bytes);
 
-    compiler.parse_input(&input_string, EMPTY_FILE)?;
-    compiler.parse_program(&program_string)?;
+    compiler.parse_inputs(&inputs_string, EMPTY_FILE)?;
+    compiler.parse_program_from_string(&program_string)?;
 
     Ok(compiler)
 }
@@ -105,8 +105,8 @@ pub fn parse_program_with_state(
     let program_string = String::from_utf8_lossy(program_bytes);
     let state_string = String::from_utf8_lossy(state_bytes);
 
-    compiler.parse_input(EMPTY_FILE, &state_string)?;
-    compiler.parse_program(&program_string)?;
+    compiler.parse_inputs(EMPTY_FILE, &state_string)?;
+    compiler.parse_program_from_string(&program_string)?;
 
     Ok(compiler)
 }
@@ -122,8 +122,8 @@ pub fn parse_program_with_input_and_state(
     let input_string = String::from_utf8_lossy(input_bytes);
     let state_string = String::from_utf8_lossy(state_bytes);
 
-    compiler.parse_input(&input_string, &state_string)?;
-    compiler.parse_program(&program_string)?;
+    compiler.parse_inputs(&inputs_string, &state_string)?;
+    compiler.parse_program_from_string(&program_string)?;
 
     Ok(compiler)
 }

leo/commands/lint.rs

@@ -0,0 +1,56 @@
+use crate::{
+    cli::*,
+    cli_types::*,
+    commands::BuildCommand,
+    directories::SOURCE_DIRECTORY_NAME,
+    errors::{CLIError, RunError},
+    files::{Manifest, MAIN_FILE_NAME},
+};
+
+use clap::ArgMatches;
+use std::{convert::TryFrom, env::current_dir};
+
+#[derive(Debug)]
+pub struct LintCommand;
+
+impl CLI for LintCommand {
+    type Options = ();
+    type Output = ();
+
+    const ABOUT: AboutType = "Lints the Leo files in the package (*)";
+    const ARGUMENTS: &'static [ArgumentType] = &[];
+    const FLAGS: &'static [FlagType] = &[];
+    const NAME: NameType = "lint";
+    const OPTIONS: &'static [OptionType] = &[];
+    const SUBCOMMANDS: &'static [SubCommandType] = &[];
+
+    #[cfg_attr(tarpaulin, skip)]
+    fn parse(_arguments: &ArgMatches) -> Result<Self::Options, CLIError> {
+        Ok(())
+    }
+
+    #[cfg_attr(tarpaulin, skip)]
+    fn output(options: Self::Options) -> Result<Self::Output, CLIError> {
+        let path = current_dir()?;
+
+        match BuildCommand::output(options)? {
+            Some((_program, _checksum_differs)) => {
+                // Get the package name
+                let _package_name = Manifest::try_from(&path)?.get_package_name();
+
+                log::info!("Unimplemented - `leo lint`");
+
+                Ok(())
+            }
+            None => {
+                let mut main_file_path = path.clone();
+                main_file_path.push(SOURCE_DIRECTORY_NAME);
+                main_file_path.push(MAIN_FILE_NAME);
+
+                Err(CLIError::RunError(RunError::MainFileDoesNotExist(
+                    main_file_path.into_os_string(),
+                )))
+            }
+        }
+    }
+}

leo/commands/mod.rs

@@ -10,6 +10,9 @@ pub use self::deploy::*;
 pub mod init;
 pub use self::init::*;
 
+pub mod lint;
+pub use self::lint::*;
+
 pub mod load;
 pub use self::load::*;
 

leo/main.rs

@@ -24,14 +24,15 @@ fn main() -> Result<(), CLIError> {
             InitCommand::new().display_order(1),
             BuildCommand::new().display_order(2),
             TestCommand::new().display_order(3),
-            LoadCommand::new().display_order(4),
-            UnloadCommand::new().display_order(5),
-            SetupCommand::new().display_order(6),
-            ProveCommand::new().display_order(7),
-            RunCommand::new().display_order(8),
-            PublishCommand::new().display_order(9),
-            DeployCommand::new().display_order(10),
-            CleanCommand::new().display_order(11),
+            LintCommand::new().display_order(4),
+            LoadCommand::new().display_order(5),
+            UnloadCommand::new().display_order(6),
+            SetupCommand::new().display_order(7),
+            ProveCommand::new().display_order(8),
+            RunCommand::new().display_order(9),
+            PublishCommand::new().display_order(10),
+            DeployCommand::new().display_order(11),
+            CleanCommand::new().display_order(12),
         ])
         .set_term_width(0)
         .get_matches();
@@ -41,6 +42,7 @@ fn main() -> Result<(), CLIError> {
         ("init", Some(arguments)) => InitCommand::process(arguments),
         ("build", Some(arguments)) => BuildCommand::process(arguments),
         ("test", Some(arguments)) => TestCommand::process(arguments),
+        ("lint", Some(arguments)) => LintCommand::process(arguments),
         ("load", Some(arguments)) => LoadCommand::process(arguments),
         ("unload", Some(arguments)) => UnloadCommand::process(arguments),
         ("setup", Some(arguments)) => SetupCommand::process(arguments),

linter/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "leo-linter"
+version = "0.1.0"
+authors = ["The Aleo Team <hello@aleo.org>"]
+edition = "2018"
+
+[dependencies]

linter/src/main.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("Hello, world!");
+}

types/Cargo.toml

@@ -4,6 +4,10 @@ version = "0.1.0"
 authors = ["The Aleo Team <hello@aleo.org>"]
 edition = "2018"
 
+[[bin]]
+name = "leo_types_ast"
+path = "src/main.rs"
+
 [dependencies]
 leo-ast = { path = "../ast", version = "0.1.0" }
 leo-input = { path = "../leo-input", version = "0.1.0" }
@@ -13,3 +17,4 @@ snarkos-models =  { git = "ssh://git@github.com/AleoHQ/snarkOS.git", package = "
 
 pest = { version = "2.0" }
 serde = { version = "1.0" }
+serde_json = { version = "1.0" }

types/src/common/identifier.rs

@@ -2,11 +2,21 @@ use crate::Span;
 use leo_ast::common::Identifier as AstIdentifier;
 use leo_input::common::Identifier as InputAstIdentifier;
 
-use serde::{Deserialize, Serialize};
-use std::fmt;
+use serde::{
+    de::{self, Visitor},
+    Deserialize,
+    Deserializer,
+    Serialize,
+    Serializer,
+};
+use std::{collections::BTreeMap, fmt};
 
 /// An identifier in the constrained program.
-#[derive(Clone, Hash, Serialize, Deserialize)]
+///
+/// Attention - When adding or removing fields from this struct,
+/// please remember to update it's Serialize and Deserialize implementation
+/// to reflect the new struct instantiation.
+#[derive(Clone, Hash)]
 pub struct Identifier {
     pub name: String,
     pub span: Span,
@@ -54,3 +64,61 @@ impl PartialEq for Identifier {
 }
 
 impl Eq for Identifier {}
+
+impl Serialize for Identifier {
+    fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+        // Converts an element that implements Serialize into a string.
+        fn to_json_string<E: Serialize, Error: serde::ser::Error>(element: &E) -> Result<String, Error> {
+            serde_json::to_string(&element).map_err(|e| Error::custom(e.to_string()))
+        }
+
+        // Load the struct elements into a BTreeMap (to preserve serialized ordering of keys).
+        let mut key: BTreeMap<String, String> = BTreeMap::new();
+        key.insert("name".to_string(), self.name.clone());
+        key.insert("span".to_string(), to_json_string(&self.span)?);
+
+        // Convert the serialized object into a string for use as a key.
+        serializer.serialize_str(&to_json_string(&key)?)
+    }
+}
+
+impl<'de> Deserialize<'de> for Identifier {
+    fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
+        struct IdentifierVisitor;
+
+        impl<'de> Visitor<'de> for IdentifierVisitor {
+            type Value = Identifier;
+
+            fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+                formatter.write_str("a string encoding the typed Identifier struct")
+            }
+
+            /// Implementation for recovering a string that serializes Identifier.
+            fn visit_str<E: de::Error>(self, value: &str) -> Result<Self::Value, E> {
+                // Converts a serialized string into an element that implements Deserialize.
+                fn to_json_string<'a, D: Deserialize<'a>, Error: serde::de::Error>(
+                    serialized: &'a str,
+                ) -> Result<D, Error> {
+                    serde_json::from_str::<'a>(serialized).map_err(|e| Error::custom(e.to_string()))
+                }
+
+                // Convert the serialized string into a BTreeMap to recover Identifier.
+                let key: BTreeMap<String, String> = to_json_string(value)?;
+
+                let name = match key.get("name") {
+                    Some(name) => name.clone(),
+                    None => return Err(E::custom("missing 'name' in serialized Identifier struct")),
+                };
+
+                let span: Span = match key.get("span") {
+                    Some(span) => to_json_string(span)?,
+                    None => return Err(E::custom("missing 'span' in serialized Identifier struct")),
+                };
+
+                Ok(Identifier { name, span })
+            }
+        }
+
+        deserializer.deserialize_str(IdentifierVisitor)
+    }
+}

types/src/imports/import.rs

@@ -6,7 +6,7 @@ use leo_ast::imports::Import as AstImport;
 use serde::{Deserialize, Serialize};
 use std::fmt;
 
-#[derive(Clone, Serialize, Deserialize)]
+#[derive(Clone, Eq, PartialEq, Serialize, Deserialize)]
 pub struct Import {
     pub package: Package,
     pub span: Span,

types/src/imports/import_symbol.rs

@@ -4,7 +4,7 @@ use leo_ast::imports::ImportSymbol as AstImportSymbol;
 use serde::{Deserialize, Serialize};
 use std::fmt;
 
-#[derive(Clone, Serialize, Deserialize)]
+#[derive(Clone, Eq, PartialEq, Serialize, Deserialize)]
 pub struct ImportSymbol {
     pub symbol: Identifier,
     pub alias: Option<Identifier>,
@@ -31,7 +31,7 @@ impl fmt::Display for ImportSymbol {
     }
 }
 
-// todo: remove this
+// TODO (collin): remove this
 impl fmt::Debug for ImportSymbol {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         if self.alias.is_some() {

types/src/imports/package.rs

@@ -4,7 +4,7 @@ use leo_ast::imports::Package as AstPackage;
 use serde::{Deserialize, Serialize};
 use std::fmt;
 
-#[derive(Clone, Serialize, Deserialize)]
+#[derive(Clone, Eq, PartialEq, Serialize, Deserialize)]
 pub struct Package {
     pub name: Identifier,
     pub access: PackageAccess,

types/src/imports/package_access.rs

@@ -4,7 +4,7 @@ use leo_ast::imports::PackageAccess as AstPackageAccess;
 use serde::{Deserialize, Serialize};
 use std::fmt;
 
-#[derive(Clone, Serialize, Deserialize)]
+#[derive(Clone, Eq, PartialEq, Serialize, Deserialize)]
 pub enum PackageAccess {
     Star(Span),
     SubPackage(Box<Package>),

types/src/lib.rs

@@ -1,3 +1,6 @@
+//! A typed syntax tree is represented as a `Program` and consists of import, circuit, and function definitions.
+//! Each defined type consists of typed statements and expressions.
+
 pub mod circuits;
 pub use self::circuits::*;
 
@@ -30,3 +33,37 @@ pub use self::statements::*;
 
 pub mod types;
 pub use self::types::*;
+
+use leo_ast::LeoAst;
+
+use serde_json;
+
+#[derive(Debug, Eq, PartialEq)]
+pub struct LeoTypedAst {
+    typed_ast: Program,
+}
+
+impl LeoTypedAst {
+    /// Creates a new typed syntax tree from a given program name and abstract syntax tree.
+    pub fn new<'ast>(program_name: &str, ast: &LeoAst<'ast>) -> Self {
+        Self {
+            typed_ast: Program::from(program_name, ast.as_repr()),
+        }
+    }
+
+    /// Returns a reference to the inner typed syntax tree representation.
+    pub fn into_repr(self) -> Program {
+        self.typed_ast
+    }
+
+    /// Serializes the typed syntax tree into a JSON string.
+    pub fn to_json_string(&self) -> Result<String, serde_json::Error> {
+        Ok(serde_json::to_string_pretty(&self.typed_ast)?)
+    }
+
+    /// Deserializes the JSON string into a typed syntax tree.
+    pub fn from_json_string(json: &str) -> Result<Self, serde_json::Error> {
+        let typed_ast: Program = serde_json::from_str(json)?;
+        Ok(Self { typed_ast })
+    }
+}

types/src/main.rs

@@ -0,0 +1,56 @@
+use leo_ast::{LeoAst, ParserError};
+use leo_types::LeoTypedAst;
+use std::{env, fs, path::Path};
+
+fn to_leo_types_tree(filepath: &Path) -> Result<String, ParserError> {
+    // Loads the Leo code as a string from the given file path.
+    let program_filepath = filepath.to_path_buf();
+    let program_string = LeoAst::load_file(&program_filepath)?;
+
+    // Parses the Leo file and constructs an abstract syntax tree.
+    let ast = LeoAst::new(&program_filepath, &program_string)?;
+
+    // Parse the abstract syntax tree and constructs a typed syntax tree.
+    let typed_ast = LeoTypedAst::new("leo_types_tree", &ast);
+
+    // Serializes the typed syntax tree into JSON format.
+    let serialized_typed_tree = LeoTypedAst::to_json_string(&typed_ast)?;
+
+    Ok(serialized_typed_tree)
+}
+
+fn main() -> Result<(), ParserError> {
+    // Parse the command-line arguments as strings.
+    let cli_arguments = env::args().collect::<Vec<String>>();
+
+    // Check that the correct number of command-line arguments were passed in.
+    if cli_arguments.len() < 2 || cli_arguments.len() > 3 {
+        eprintln!("Warning - an invalid number of command-line arguments were provided.");
+        println!(
+            "\nCommand-line usage:\n\n\tleo_types_ast {{PATH/TO/INPUT_FILENAME}}.leo {{PATH/TO/OUTPUT_DIRECTORY (optional)}}\n"
+        );
+        return Ok(()); // Exit innocently
+    }
+
+    // Construct the input filepath.
+    let input_filepath = Path::new(&cli_arguments[1]);
+
+    // Construct the serialized typed syntax tree.
+    let serialized_typed_tree = to_leo_types_tree(&input_filepath)?;
+    println!("{}", serialized_typed_tree);
+
+    // Determine the output directory.
+    let output_directory = match cli_arguments.len() == 3 {
+        true => format!(
+            "{}/{}.json",
+            cli_arguments[2],
+            input_filepath.file_stem().unwrap().to_str().unwrap()
+        ),
+        false => format!("./{}.json", input_filepath.file_stem().unwrap().to_str().unwrap()),
+    };
+
+    // Write the serialized abstract syntax tree to the output directory.
+    fs::write(Path::new(&output_directory), serialized_typed_tree)?;
+
+    Ok(())
+}

types/src/program.rs

@@ -8,7 +8,7 @@ use serde::{Deserialize, Serialize};
 use std::collections::HashMap;
 
 /// A simple program with statement expressions, program arguments and program returns.
-#[derive(Debug, Clone, Serialize, Deserialize)]
+#[derive(Debug, Clone, Eq, PartialEq, Serialize, Deserialize)]
 pub struct Program {
     pub name: String,
     pub expected_input: Vec<InputVariable>,
@@ -22,10 +22,11 @@ const MAIN_FUNCTION_NAME: &str = "main";
 
 impl<'ast> Program {
     //! Logic to convert from an abstract syntax tree (ast) representation to a Leo program.
-    pub fn from(file: File<'ast>, name: String) -> Self {
+    pub fn from(program_name: &str, program_ast: &File<'ast>) -> Self {
         // Compiled ast -> aleo program representation
-        let imports = file
+        let imports = program_ast
             .imports
+            .to_owned()
             .into_iter()
             .map(|import| Import::from(import))
             .collect::<Vec<Import>>();
@@ -35,23 +36,23 @@ impl<'ast> Program {
         let mut tests = HashMap::new();
         let mut expected_input = vec![];
 
-        file.circuits.into_iter().for_each(|circuit| {
+        program_ast.circuits.to_owned().into_iter().for_each(|circuit| {
             circuits.insert(Identifier::from(circuit.identifier.clone()), Circuit::from(circuit));
         });
-        file.functions.into_iter().for_each(|function_def| {
+        program_ast.functions.to_owned().into_iter().for_each(|function_def| {
             let function = Function::from(function_def);
             if function.function_name.name.eq(MAIN_FUNCTION_NAME) {
                 expected_input = function.input.clone();
             }
             functions.insert(function.function_name.clone(), function);
         });
-        file.tests.into_iter().for_each(|test_def| {
+        program_ast.tests.to_owned().into_iter().for_each(|test_def| {
             let test = TestFunction::from(test_def);
             tests.insert(test.0.function_name.clone(), test);
         });
 
         Self {
-            name,
+            name: program_name.to_string(),
             expected_input,
             imports,
             circuits,

types/tests/mod.rs

@@ -0,0 +1 @@
+mod serialization;

types/tests/serialization/expected_typed_ast.json

@@ -0,0 +1,66 @@
+{
+  "name": "leo_types_tree",
+  "expected_inputs": [],
+  "imports": [],
+  "circuits": {},
+  "functions": {
+    "{\"name\":\"main\",\"span\":\"{\\\"text\\\":\\\" function main() {\\\",\\\"line\\\":1,\\\"start\\\":10,\\\"end\\\":14}\"}": {
+      "function_name": "{\"name\":\"main\",\"span\":\"{\\\"text\\\":\\\" function main() {\\\",\\\"line\\\":1,\\\"start\\\":10,\\\"end\\\":14}\"}",
+      "inputs": [],
+      "returns": [],
+      "statements": [
+        {
+          "Return": [
+            [
+              {
+                "Add": [
+                  {
+                    "Implicit": [
+                      "1",
+                      {
+                        "text": "     return 1 + 1",
+                        "line": 2,
+                        "start": 12,
+                        "end": 13
+                      }
+                    ]
+                  },
+                  {
+                    "Implicit": [
+                      "1",
+                      {
+                        "text": "     return 1 + 1",
+                        "line": 2,
+                        "start": 16,
+                        "end": 17
+                      }
+                    ]
+                  },
+                  {
+                    "text": "     return 1 + 1",
+                    "line": 2,
+                    "start": 12,
+                    "end": 17
+                  }
+                ]
+              }
+            ],
+            {
+              "text": "     return 1 + 1",
+              "line": 2,
+              "start": 5,
+              "end": 17
+            }
+          ]
+        }
+      ],
+      "span": {
+        "text": " function main() {",
+        "line": 1,
+        "start": 1,
+        "end": 1
+      }
+    }
+  },
+  "tests": {}
+}

types/tests/serialization/json.rs

@@ -0,0 +1,76 @@
+use leo_ast::LeoAst;
+use leo_types::LeoTypedAst;
+
+use std::path::PathBuf;
+
+fn to_typed_ast(program_filepath: &PathBuf) -> LeoTypedAst {
+    // Loads the Leo code as a string from the given file path.
+    let program_string = LeoAst::load_file(program_filepath).unwrap();
+
+    // Parses the Leo file and constructs an abstract syntax tree.
+    let ast = LeoAst::new(&program_filepath, &program_string).unwrap();
+
+    // Parse the abstract syntax tree and constructs a typed syntax tree.
+    let typed_ast = LeoTypedAst::new("leo_types_tree", &ast);
+
+    typed_ast
+}
+
+#[test]
+fn test_serialize() {
+    // Construct a typed syntax tree from the given test file.
+    let typed_ast = {
+        let mut program_filepath = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
+        program_filepath.push("tests/serialization/main.leo");
+
+        to_typed_ast(&program_filepath)
+    };
+
+    // Serializes the typed syntax tree into JSON format.
+    let serialized_typed_ast = typed_ast.to_json_string().unwrap();
+
+    // Load the expected typed syntax tree.
+    let expected = include_str!("expected_typed_ast.json");
+
+    println!("{}", serialized_typed_ast);
+    assert_eq!(expected, serialized_typed_ast);
+}
+
+#[test]
+fn test_deserialize() {
+    // Load the expected typed syntax tree.
+    let expected_typed_ast = {
+        let mut program_filepath = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
+        program_filepath.push("tests/serialization/main.leo");
+
+        to_typed_ast(&program_filepath)
+    };
+
+    // Construct a typed syntax tree by deserializing a typed syntax tree JSON file.
+    let serialized_typed_ast = include_str!("expected_typed_ast.json");
+    let typed_ast = LeoTypedAst::from_json_string(serialized_typed_ast).unwrap();
+
+    assert_eq!(expected_typed_ast, typed_ast);
+}
+
+#[test]
+fn test_serialize_deserialize_serialize() {
+    // Construct a typed syntax tree from the given test file.
+    let typed_ast = {
+        let mut program_filepath = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
+        program_filepath.push("tests/serialization/main.leo");
+
+        to_typed_ast(&program_filepath)
+    };
+
+    // Serializes the typed syntax tree into JSON format.
+    let serialized_typed_ast = typed_ast.to_json_string().unwrap();
+
+    // Deserializes the typed syntax tree into a LeoTypedAst.
+    let typed_ast = LeoTypedAst::from_json_string(&serialized_typed_ast).unwrap();
+
+    // Reserializes the typed syntax tree into JSON format.
+    let reserialized_typed_ast = typed_ast.to_json_string().unwrap();
+
+    assert_eq!(serialized_typed_ast, reserialized_typed_ast);
+}

types/tests/serialization/main.leo

@@ -0,0 +1,3 @@
+function main() {
+    return 1 + 1
+}

types/tests/serialization/mod.rs

@@ -0,0 +1 @@
+mod json;