chore: Add clippy lints (#529)

Lints are added (deny) at crate level.

In each offending file, the failing lints are explicitly allowed.
Each file will be fixed in subsequent PRs.

Signed-off-by: Anand Krishnamoorthi <anakrish@microsoft.com>

Author: anakrish

.github/actions/toolchains/rust/action.yml

@@ -4,7 +4,7 @@ inputs:
   toolchain:
     description: 'Rust toolchain version'
     required: false
-    default: '1.89.0'
+    default: '1.92.0'
   components:
     description: 'Additional components to install'
     required: false

README.md

@@ -3,7 +3,7 @@
 **Regorus** is
 
   - *Rego*-*Rus(t)*  - A fast, light-weight [Rego](https://www.openpolicyagent.org/docs/latest/policy-language/)
-   interpreter written in Rust.
+    interpreter written in Rust.
   - *Rigorous* - A rigorous enforcer of well-defined Rego semantics.
 
 Regorus is also

src/ast.rs

@@ -1,3 +1,4 @@
+#![allow(clippy::missing_const_for_fn, clippy::pattern_type_mismatch)]
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 

src/builtins/aggregates.rs

@@ -1,6 +1,8 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
+#![allow(clippy::pattern_type_mismatch)]
+
 use crate::ast::{Expr, Ref};
 use crate::builtins;
 use crate::builtins::utils::{ensure_args_count, ensure_numeric};

src/builtins/arrays.rs

@@ -1,5 +1,6 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
+#![allow(clippy::as_conversions)]
 
 use crate::ast::{Expr, Ref};
 use crate::builtins;

src/builtins/comparison.rs

@@ -1,6 +1,8 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
+#![allow(clippy::pattern_type_mismatch)]
+
 use crate::ast::BoolOp;
 use crate::value::Value;
 

src/builtins/conversions.rs

@@ -1,6 +1,8 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
+#![allow(clippy::unseparated_literal_suffix, clippy::pattern_type_mismatch)]
+
 use crate::ast::{Expr, Ref};
 use crate::builtins;
 use crate::builtins::utils::ensure_args_count;

src/builtins/encoding.rs

@@ -1,5 +1,6 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
+#![allow(clippy::unused_trait_names, clippy::pattern_type_mismatch)]
 
 use crate::ast::{Expr, Ref};
 use crate::builtins;

src/builtins/glob.rs

@@ -1,6 +1,8 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
+#![allow(clippy::pattern_type_mismatch)]
+
 use crate::ast::{Expr, Ref};
 use crate::builtins;
 use crate::builtins::utils::{ensure_args_count, ensure_string, ensure_string_collection};

src/builtins/graph.rs

@@ -1,6 +1,8 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
+#![allow(clippy::pattern_type_mismatch)]
+
 use crate::ast::{Expr, Ref};
 use crate::builtins;
 use crate::builtins::utils::{ensure_args_count, ensure_object};