From 08ca90a1368656421d5eac440bc27634aa7280d9 Mon Sep 17 00:00:00 2001
From: Stephen Chung <Stephen.Chung@intexact.com>
Date: Fri, 2 Oct 2020 18:52:18 +0800
Subject: [PATCH] Use ImmutableString for import alias.

---
 src/engine.rs | 9 ++++++---
 src/parser.rs | 4 ++--
 src/syntax.rs | 4 ++--
 3 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/src/engine.rs b/src/engine.rs
index cceda886..0bde53c6 100644
--- a/src/engine.rs
+++ b/src/engine.rs
@@ -36,7 +36,6 @@ use crate::utils::ImmutableString;
 use crate::any::DynamicWriteLock;
 
 use crate::stdlib::{
-    borrow::Cow,
     boxed::Box,
     collections::{HashMap, HashSet},
     fmt, format,
@@ -70,7 +69,11 @@ pub type Map = HashMap<ImmutableString, Dynamic>;
 /// ## WARNING
 ///
 /// This type is volatile and may change.
-pub type Imports<'a> = Vec<(Cow<'a, str>, Module)>;
+//
+// Note - We cannot use &str or Cow<str> here because `eval` may load a module
+//        and the module name will live beyond the AST of the eval script text.
+//        The best we can do is a shared reference.
+pub type Imports = Vec<(ImmutableString, Module)>;
 
 #[cfg(not(feature = "unchecked"))]
 #[cfg(debug_assertions)]
@@ -1826,7 +1829,7 @@ impl Engine {
 
                         if let Some((name, _)) = alias {
                             module.index_all_sub_modules();
-                            mods.push((name.clone().into(), module));
+                            mods.push((name.clone(), module));
                         }
 
                         state.modules += 1;
diff --git a/src/parser.rs b/src/parser.rs
index 356429eb..4618f041 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -592,7 +592,7 @@ pub enum Stmt {
     ReturnWithVal(Box<((ReturnType, Position), Option<Expr>, Position)>),
     /// import expr as module
     #[cfg(not(feature = "no_module"))]
-    Import(Box<(Expr, Option<(String, Position)>, Position)>),
+    Import(Box<(Expr, Option<(ImmutableString, Position)>, Position)>),
     /// expr id as name, ...
     #[cfg(not(feature = "no_module"))]
     Export(
@@ -2753,7 +2753,7 @@ fn parse_import(
 
     Ok(Stmt::Import(Box::new((
         expr,
-        Some((name, settings.pos)),
+        Some((name.into(), settings.pos)),
         token_pos,
     ))))
 }
diff --git a/src/syntax.rs b/src/syntax.rs
index cf9c9519..9f3f7f36 100644
--- a/src/syntax.rs
+++ b/src/syntax.rs
@@ -74,8 +74,8 @@ impl fmt::Debug for CustomSyntax {
 
 /// Context of a script evaluation process.
 #[derive(Debug)]
-pub struct EvalContext<'a, 'b: 'a, 's, 'm, 't, 'd: 't> {
-    pub(crate) mods: &'a mut Imports<'b>,
+pub struct EvalContext<'a, 's, 'm, 't, 'd: 't> {
+    pub(crate) mods: &'a mut Imports,
     pub(crate) state: &'s mut State,
     pub(crate) lib: &'m Module,
     pub(crate) this_ptr: &'t mut Option<&'d mut Dynamic>,