feat(minifier): handle direct eval calls

crates/oxc_minifier/docs/ASSUMPTIONS.md

@@ -88,14 +88,14 @@ const v = [];
 class A extends v {} // TypeError
 ```
 
-### No Direct `eval` or `Function` Constructor
+### Variables declared in direct `eval` are not referenced outside the eval
 
-Code doesn't dynamically evaluate strings as code. We intend to change this assumption to optional in the future.
+Variables declared in direct `eval` are not referenced outside the eval, which is only allowed in non-strict mode.
 
 ```javascript
 // The minifier assumes this never happens:
 eval('var x = 1');
-new Function('return x');
+console.log(x); // 1
 ```
 
 ### No side effects from accessing to a global variable named `arguments`

crates/oxc_minifier/src/peephole/minimize_statements.rs

@@ -1131,10 +1131,9 @@ impl<'a> PeepholeOptimizations {
         ctx: &Ctx<'a, '_>,
         non_scoped_literal_only: bool,
     ) -> bool {
-        // TODO: we should skip this compression when direct eval exists
-        //       because the code inside eval may reference the variable
-
-        if Self::keep_top_level_var_in_script_mode(ctx) {
+        if Self::keep_top_level_var_in_script_mode(ctx)
+            || ctx.current_scope_flags().contains_direct_eval()
+        {
             return false;
         }
 
@@ -1169,30 +1168,32 @@ impl<'a> PeepholeOptimizations {
         declarations: &mut Vec<'a, VariableDeclarator<'a>>,
         ctx: &Ctx<'a, '_>,
     ) -> bool {
-        // TODO: we should skip this compression when direct eval exists
-        //       because the code inside eval may reference the variable
+        if Self::keep_top_level_var_in_script_mode(ctx)
+            || ctx.current_scope_flags().contains_direct_eval()
+            || kind.is_using()
+        {
+            return false;
+        }
 
         let mut changed = false;
-        if !Self::keep_top_level_var_in_script_mode(ctx) && !kind.is_using() {
-            let mut i = 1;
-            while i < declarations.len() {
-                let (prev_decls, [decl, ..]) = declarations.split_at_mut(i) else { unreachable!() };
-                let Some(decl_init) = &mut decl.init else {
-                    i += 1;
-                    continue;
-                };
-                let old_len = prev_decls.len();
-                let new_len = Self::substitute_single_use_symbol_in_expression_from_declarators(
-                    decl_init, prev_decls, ctx, false,
-                );
-                if old_len != new_len {
-                    changed = true;
-                    let drop_count = old_len - new_len;
-                    declarations.drain(i - drop_count..i);
-                    i -= drop_count;
-                }
+        let mut i = 1;
+        while i < declarations.len() {
+            let (prev_decls, [decl, ..]) = declarations.split_at_mut(i) else { unreachable!() };
+            let Some(decl_init) = &mut decl.init else {
                 i += 1;
+                continue;
+            };
+            let old_len = prev_decls.len();
+            let new_len = Self::substitute_single_use_symbol_in_expression_from_declarators(
+                decl_init, prev_decls, ctx, false,
+            );
+            if old_len != new_len {
+                changed = true;
+                let drop_count = old_len - new_len;
+                declarations.drain(i - drop_count..i);
+                i -= drop_count;
             }
+            i += 1;
         }
         changed
     }

crates/oxc_minifier/src/peephole/normalize.rs

@@ -178,7 +178,11 @@ impl<'a> Normalize {
     fn convert_const_to_let(decl: &mut VariableDeclaration<'a>, ctx: &TraverseCtx<'a>) {
         // checking whether the current scope is the root scope instead of
         // checking whether any variables are exposed to outside (e.g. `export` in ESM)
-        if decl.kind.is_const() && ctx.current_scope_id() != ctx.scoping().root_scope_id() {
+        if decl.kind.is_const()
+            && ctx.current_scope_id() != ctx.scoping().root_scope_id()
+            // direct eval may have a assignment inside
+            && !ctx.current_scope_flags().contains_direct_eval()
+        {
             let all_declarations_are_only_read =
                 decl.declarations.iter().flat_map(|d| d.id.get_binding_identifiers()).all(|id| {
                     ctx.scoping()
@@ -429,6 +433,7 @@ mod test {
         test_same("const x = 1"); // keep top-level (can be replaced with "let" if it's ESM and not exported)
         test("{ const x = 1 }", "{ let x = 1 }");
         test_same("{ const x = 1; x = 2 }"); // keep assign error
+        test_same("{ const x = 1; eval('x = 2') }"); // keep assign error
         test("{ const x = 1, y = 2 }", "{ let x = 1, y = 2 }");
         test("{ const { x } = { x: 1 } }", "{ let { x } = { x: 1 } }");
         test("{ const [x] = [1] }", "{ let [x] = [1] }");

crates/oxc_minifier/src/peephole/remove_unused_declaration.rs

@@ -52,7 +52,9 @@ impl<'a> PeepholeOptimizations {
         }
         let Some(id) = &f.id else { return };
         let Some(symbol_id) = id.symbol_id.get() else { return };
-        if Self::keep_top_level_var_in_script_mode(ctx) {
+        if Self::keep_top_level_var_in_script_mode(ctx)
+            || ctx.current_scope_flags().contains_direct_eval()
+        {
             return;
         }
         if !ctx.scoping().symbol_is_unused(symbol_id) {
@@ -69,7 +71,9 @@ impl<'a> PeepholeOptimizations {
         }
         let Some(id) = &c.id else { return };
         let Some(symbol_id) = id.symbol_id.get() else { return };
-        if Self::keep_top_level_var_in_script_mode(ctx) {
+        if Self::keep_top_level_var_in_script_mode(ctx)
+            || ctx.current_scope_flags().contains_direct_eval()
+        {
             return;
         }
         if !ctx.scoping().symbol_is_unused(symbol_id) {
@@ -129,11 +133,17 @@ mod test {
         test_options("function foo() {}", "", &options);
         test_same_options("function foo() { bar } foo()", &options);
         test_same_options("export function foo() {} foo()", &options);
+        test_same_options("function foo() { bar } eval('foo()')", &options);
     }
 
     #[test]
     fn remove_unused_class_declaration() {
         let options = CompressOptions::smallest();
+        test_options("class C {}", "", &options);
+        test_same_options("export class C {}", &options);
+        test_options("class C {} C", "", &options);
+        test_same_options("class C {} eval('C')", &options);
+
         // extends
         test_options("class C {}", "", &options);
         test_options("class C extends Foo {}", "Foo", &options);

crates/oxc_minifier/src/peephole/remove_unused_expression.rs

@@ -636,7 +636,9 @@ impl<'a> PeepholeOptimizations {
         else {
             return false;
         };
-        if Self::keep_top_level_var_in_script_mode(ctx) {
+        if Self::keep_top_level_var_in_script_mode(ctx)
+            || ctx.current_scope_flags().contains_direct_eval()
+        {
             return false;
         }
         let reference_id = ident.reference_id();
@@ -1076,6 +1078,7 @@ mod test {
         let options = CompressOptions::smallest();
         test_options("var x = 1; x = 2;", "", &options);
         test_options("var x = 1; x = foo();", "foo()", &options);
+        test_same_options("var x = 1; x = 2, eval('x')", &options);
         test_same_options("export var foo; foo = 0;", &options);
         test_same_options("var x = 1; x = 2, foo(x)", &options);
         test_same_options("function foo() { return t = x(); } foo();", &options);

crates/oxc_minifier/src/peephole/remove_unused_private_members.rs

@@ -11,6 +11,10 @@ impl<'a> PeepholeOptimizations {
     /// This function uses the private member usage collected during the main traverse
     /// to remove unused private fields and methods from the class body.
     pub fn remove_unused_private_members(body: &mut ClassBody<'a>, ctx: &mut Ctx<'a, '_>) {
+        if ctx.current_scope_flags().contains_direct_eval() {
+            return;
+        }
+
         let old_len = body.body.len();
         body.body.retain(|element| match element {
             ClassElement::PropertyDefinition(prop) => {
@@ -113,6 +117,7 @@ mod test {
             "class C { public = 1; #used = 3; method() { return this.public + this.#used; } } new C();",
         );
         test_same("class C { #unused = foo(); method() { return 1; } } new C();");
+        test_same("class C { #used = 1; method() { return eval('this.#used'); } } new C();");
     }
 
     #[test]
@@ -129,6 +134,9 @@ mod test {
         test_same(
             "class C { #helper() { return 1; } method() { return this.#helper(); } } new C();",
         );
+        test_same(
+            "class C { #helper() { return 1; } method() { return eval('this.#helper()'); } } new C();",
+        );
     }
 
     #[test]

crates/oxc_minifier/tests/peephole/inline_single_use_variable.rs

@@ -26,6 +26,7 @@ fn test_keep_names(source_text: &str, expected: &str) {
 fn test_inline_single_use_variable() {
     test_same("function wrapper(arg0, arg1) {using x = foo; return x}");
     test_same("async function wrapper(arg0, arg1) { await using x = foo; return x}");
+    test_same("function wrapper(arg0) { eval('x'); var x = arg0; return x }");
 
     test(
         "
@@ -251,6 +252,8 @@ fn test_inline_past_readonly_variable() {
 
 #[test]
 fn test_within_same_variable_declarations() {
+    test_same("function wrapper() { eval('a'); for (var a = foo, b = a; bar;) return b }");
+
     test_script(
         "var a = foo, b = a; for (; bar;) console.log(b)",
         "for (var a = foo, b = a; bar;) console.log(b)",

tasks/track_memory_allocations/allocs_parser.snap

@@ -1,14 +1,14 @@
 File                       | File size      || Sys allocs     | Sys reallocs   || Arena allocs   | Arena reallocs | Arena bytes    
 -------------------------------------------------------------------------------------------------------------------------------------------
-checker.ts                 | 2.92 MB        ||          10157 |             21 ||         268665 |          23341
+checker.ts                 | 2.92 MB        ||          10163 |             21 ||         268665 |          23341
 
-cal.com.tsx                | 1.06 MB        ||           2197 |             54 ||         138188 |          13712
+cal.com.tsx                | 1.06 MB        ||           2205 |             61 ||         138188 |          13712
 
 RadixUIAdoptionSection.jsx | 2.52 kB        ||              1 |              0 ||            365 |             66
 
-pdf.mjs                    | 567.30 kB      ||            683 |             71 ||          90678 |           8148
+pdf.mjs                    | 567.30 kB      ||            701 |             75 ||          90678 |           8148
 
-antd.js                    | 6.69 MB        ||           6938 |            236 ||         528505 |          55357
+antd.js                    | 6.69 MB        ||           6995 |            235 ||         528505 |          55357
 
 binder.ts                  | 193.08 kB      ||            537 |              7 ||          16807 |           1475