From abe6b4a29bd1e3e05e966f52f82066b3bc2406fc Mon Sep 17 00:00:00 2001
From: Stephen Chung <schungx@live.com>
Date: Sat, 27 Nov 2021 14:24:06 +0800
Subject: [PATCH] Use more const functions.

---
 Cargo.toml                    |  2 +-
 src/engine.rs                 |  2 +-
 src/func/hashing.rs           |  2 +-
 src/module/resolvers/file.rs  |  4 ++--
 src/optimizer.rs              |  4 ++--
 src/parser.rs                 | 17 +++++++++++------
 src/types/immutable_string.rs |  2 +-
 7 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 11012109..0055ed88 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -19,7 +19,7 @@ categories = ["no-std", "embedded", "wasm", "parser-implementations"]
 smallvec = { version = "1.7", default-features = false, features = ["union", "const_new" ] }
 ahash = { version = "0.7", default-features = false }
 num-traits = { version = "0.2", default-features = false }
-smartstring = { version = "0.2.7", default-features = false }
+smartstring = { version = "0.2.8", default-features = false }
 rhai_codegen = { version = "1.2", path = "codegen", default-features = false }
 
 [features]
diff --git a/src/engine.rs b/src/engine.rs
index 01ddc4f4..f35509e2 100644
--- a/src/engine.rs
+++ b/src/engine.rs
@@ -1159,7 +1159,7 @@ impl Engine {
             progress: None,
 
             #[cfg(not(feature = "no_optimize"))]
-            optimization_level: Default::default(),
+            optimization_level: crate::OptimizationLevel::default(),
 
             #[cfg(not(feature = "unchecked"))]
             limits: Limits::new(),
diff --git a/src/func/hashing.rs b/src/func/hashing.rs
index 8d360c04..a681fa04 100644
--- a/src/func/hashing.rs
+++ b/src/func/hashing.rs
@@ -49,7 +49,7 @@ impl BuildHasher for StraightHasherBuilder {
 #[inline(always)]
 #[must_use]
 pub fn get_hasher() -> ahash::AHasher {
-    Default::default()
+    ahash::AHasher::default()
 }
 
 /// Calculate a [`u64`] hash key from a namespace-qualified variable name.
diff --git a/src/module/resolvers/file.rs b/src/module/resolvers/file.rs
index 7af23527..5af89136 100644
--- a/src/module/resolvers/file.rs
+++ b/src/module/resolvers/file.rs
@@ -121,7 +121,7 @@ impl FileModuleResolver {
             base_path: None,
             extension: extension.into(),
             cache_enabled: true,
-            cache: Default::default(),
+            cache: BTreeMap::new().into(),
         }
     }
 
@@ -150,7 +150,7 @@ impl FileModuleResolver {
             base_path: Some(path.into()),
             extension: extension.into(),
             cache_enabled: true,
-            cache: Default::default(),
+            cache: BTreeMap::new().into(),
         }
     }
 
diff --git a/src/optimizer.rs b/src/optimizer.rs
index af1740cd..620923b7 100644
--- a/src/optimizer.rs
+++ b/src/optimizer.rs
@@ -1119,7 +1119,7 @@ pub fn optimize_into_ast(
     optimization_level: OptimizationLevel,
 ) -> AST {
     let level = if cfg!(feature = "no_optimize") {
-        Default::default()
+        OptimizationLevel::default()
     } else {
         optimization_level
     };
@@ -1140,7 +1140,7 @@ pub fn optimize_into_ast(
                 .map(|fn_def| crate::ast::ScriptFnDef {
                     name: fn_def.name.clone(),
                     access: fn_def.access,
-                    body: crate::ast::StmtBlock::empty(Position::NONE),
+                    body: crate::ast::StmtBlock::NONE,
                     params: fn_def.params.clone(),
                     lib: None,
                     #[cfg(not(feature = "no_module"))]
diff --git a/src/parser.rs b/src/parser.rs
index 279e2593..f6bd9259 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -57,13 +57,18 @@ pub struct IdentifierBuilder(
 
 impl IdentifierBuilder {
     /// Create a new IdentifierBuilder.
+    #[cfg(not(feature = "no_smartstring"))]
+    #[inline]
+    #[must_use]
+    pub const fn new() -> Self {
+        Self()
+    }
+    /// Create a new IdentifierBuilder.
+    #[cfg(feature = "no_smartstring")]
     #[inline]
     #[must_use]
     pub fn new() -> Self {
-        Self(
-            #[cfg(feature = "no_smartstring")]
-            std::collections::BTreeSet::new(),
-        )
+        Self(std::collections::BTreeSet::new())
     }
     /// Get an identifier from a text string.
     #[inline]
@@ -2013,8 +2018,8 @@ fn parse_custom_syntax(
     if syntax.scope_may_be_changed {
         // Add a barrier variable to the stack so earlier variables will not be matched.
         // Variable searches stop at the first barrier.
-        let empty = state.get_identifier(SCOPE_SEARCH_BARRIER_MARKER);
-        state.stack.push((empty, AccessMode::ReadWrite));
+        let marker = state.get_identifier(SCOPE_SEARCH_BARRIER_MARKER);
+        state.stack.push((marker, AccessMode::ReadWrite));
     }
 
     let parse_func = syntax.parse.as_ref();
diff --git a/src/types/immutable_string.rs b/src/types/immutable_string.rs
index 5b446eb0..be5d4c91 100644
--- a/src/types/immutable_string.rs
+++ b/src/types/immutable_string.rs
@@ -539,7 +539,7 @@ impl ImmutableString {
     /// Create a new [`ImmutableString`].
     #[inline(always)]
     pub fn new() -> Self {
-        Self(SmartString::new().into())
+        Self(SmartString::new_const().into())
     }
     /// Consume the [`ImmutableString`] and convert it into a [`String`].
     /// If there are other references to the same string, a cloned copy is returned.