fix(es/resolver): Correctly check strict mode (#8851)

**Related issue:** - Closes #8842

Author: Austaras

crates/swc_ecma_minifier/tests/terser/compress/dead_code/dead_code_2_should_warn_strict/output.js

@@ -1,6 +1,6 @@
 "use strict";
 function f() {
- var x, g;
+ var x, g1;
  g();
  x = 10;
  throw Error("foo");

crates/swc_ecma_minifier/tests/terser/compress/dead_code/dead_code_2_should_warn_strict/output.mangleOnly.js

@@ -1,6 +1,6 @@
 "use strict";
 function n() {
- o();
+ g();
  n = 10;
  throw new Error("foo");
  if (n) {

crates/swc_ecma_transforms_base/src/resolver/mod.rs

@@ -558,11 +558,14 @@ impl<'a> VisitMut for Resolver<'a> {
  child.mark_block(&mut s.span);
 
  let old_strict_mode = child.strict_mode;
- child.strict_mode = s
- .stmts
- .first()
- .map(|stmt| stmt.is_use_strict())
- .unwrap_or(false);
+
+ if !child.strict_mode {
+ child.strict_mode = s
+ .stmts
+ .first()
+ .map(|stmt| stmt.is_use_strict())
+ .unwrap_or(false);
+ }
  // Prevent creating new scope.
  s.stmts.visit_mut_with(child);
  child.strict_mode = old_strict_mode;
@@ -901,11 +904,13 @@ impl<'a> VisitMut for Resolver<'a> {
  Some(body) => {
  self.mark_block(&mut body.span);
  let old_strict_mode = self.strict_mode;
- self.strict_mode = body
- .stmts
- .first()
- .map(|stmt| stmt.is_use_strict())
- .unwrap_or(false);
+ if !self.strict_mode {
+ self.strict_mode = body
+ .stmts
+ .first()
+ .map(|stmt| stmt.is_use_strict())
+ .unwrap_or(false);
+ }
  // Prevent creating new scope.
  body.visit_mut_children_with(self);
  self.strict_mode = old_strict_mode;

crates/swc_ecma_transforms_base/tests/fixture.rs

@@ -10,7 +10,7 @@ use swc_ecma_visit::{
 };
 use testing::{fixture, run_test2, NormalizedOutput};
 
-pub fn print(cm: Lrc<SourceMap>, module: &Module) -> String {
+pub fn print(cm: Lrc<SourceMap>, program: &Program) -> String {
  let mut buf = vec![];
  {
  let mut emitter = Emitter {
@@ -23,7 +23,7 @@ pub fn print(cm: Lrc<SourceMap>, module: &Module) -> String {
  };
 
  // println!("Emitting: {:?}", module);
- emitter.emit_module(module).unwrap();
+ emitter.emit_program(program).unwrap();
  }
 
  let s = String::from_utf8_lossy(&buf);
@@ -47,15 +47,15 @@ where
  let lexer = Lexer::new(syntax, EsVersion::latest(), StringInput::from(&*fm), None);
  let mut parser = Parser::new_from(lexer);
 
- let module = parser
- .parse_module()
+ let program = parser
+ .parse_program()
  .map_err(|err| err.into_diagnostic(&handler).emit())?;
 
  let mut folder = op();
 
- let module = module.fold_with(&mut folder);
+ let program = program.fold_with(&mut folder);
 
- let actual = print(cm, &module);
+ let actual = print(cm, &program);
  let actual = NormalizedOutput::from(actual);
 
  actual.compare_to_file(&output).unwrap();

crates/swc_ecma_transforms_base/tests/resolver/function/block/input.js

@@ -0,0 +1,12 @@
+export function k() {
+ function x() {
+ console.log("hi");
+ }
+ {
+ function x() {
+ console.log("merong");
+ }
+ }
+ return x;
+}
+k();

crates/swc_ecma_transforms_base/tests/resolver/function/block/output.js

@@ -0,0 +1,12 @@
+export function k__2() {
+ function x__3() {
+ console.log("hi");
+ }
+ {
+ function x__5() {
+ console.log("merong");
+ }
+ }
+ return x__3;
+}
+k__2();

crates/swc_ecma_transforms_base/tests/resolver/issues/6310/output.js

@@ -1,4 +1,4 @@
 switch(0){
- case x__3:
- function x__3() {}
+ case x__2:
+ function x__2() {}
 }

crates/swc_ecma_transforms_base/tests/resolver/issues/7685/output.js

@@ -2,4 +2,4 @@ var NaN__2 = 1;
 {
  let NaN__3 = 1;
  console.log(NaN__3);
-}console.log(NaN__2);
+}console.log(NaN);

crates/swc_ecma_transforms_base/tests/resolver/minifier/10/output.js

@@ -1,2 +1,2 @@
 var NaN__2;
-console.log(NaN__2.toString());
+console.log(NaN.toString());

crates/swc_ecma_transforms_base/tests/resolver/minifier/11/output.js

@@ -1,2 +1,2 @@
 var NaN__2 = 5;
-console.log(NaN__2.toString());
+console.log(NaN.toString());