Fix bugs (#683)

- Fix block_scoping (Fix #682)
 - Handle new.target in susbscript position (Fix #675)

ecmascript/parser/src/parser/expr.rs

@@ -413,10 +413,12 @@ impl<'a, I: Tokens> Parser<'a, I> {
             if eat!('.') {
                 let start_of_target = cur_pos!();
                 if eat!("target") {
-                    return Ok(Box::new(Expr::MetaProp(MetaPropExpr {
+                    let expr = Box::new(Expr::MetaProp(MetaPropExpr {
                         meta: Ident::new(js_word!("new"), span_of_new),
                         prop: Ident::new(js_word!("target"), span!(start_of_target)),
-                    })));
+                    }));
+
+                    return self.parse_subscripts(ExprOrSuper::Expr(expr), true);
                 }
 
                 unexpected!()

ecmascript/parser/src/parser/expr/tests.rs

@@ -418,6 +418,11 @@ fn issue_380() {
     );
 }
 
+#[test]
+fn issue_675() {
+    expr("Object.setPrototypeOf(this, new.target.prototype)");
+}
+
 #[bench]
 fn bench_new_expr_ts(b: &mut Bencher) {
     bench_parser(

ecmascript/transforms/src/compat/es2015/block_scoping.rs

@@ -21,7 +21,11 @@ use swc_ecma_utils::{
 /// }
 /// ```
 pub fn block_scoping() -> impl Pass {
-    BlockScoping::default()
+    BlockScoping {
+        scope: Default::default(),
+        vars: vec![],
+        var_decl_kind: VarDeclKind::Var,
+    }
 }
 
 type ScopeStack = SmallVec<[ScopeKind; 8]>;
@@ -39,10 +43,10 @@ enum ScopeKind {
     Block,
 }
 
-#[derive(Default)]
 struct BlockScoping {
     scope: ScopeStack,
     vars: Vec<VarDeclarator>,
+    var_decl_kind: VarDeclKind,
 }
 
 noop_fold_type!(BlockScoping);
@@ -99,6 +103,14 @@ impl BlockScoping {
 
     fn handle_vars(&mut self, body: Box<Stmt>) -> Box<Stmt> {
         body.map(|body| {
+            {
+                let mut v = FunctionFinder { found: false };
+                body.visit_with(&mut v);
+                if !v.found {
+                    return body;
+                }
+            }
+
             //
             if let Some(ScopeKind::ForLetLoop { args, used, .. }) = self.scope.pop() {
                 if used.is_empty() {
@@ -330,8 +342,12 @@ impl Fold<SetterProp> for BlockScoping {
 
 impl Fold<VarDecl> for BlockScoping {
     fn fold(&mut self, var: VarDecl) -> VarDecl {
+        let old = self.var_decl_kind;
+        self.var_decl_kind = var.kind;
         let var = var.fold_children(self);
 
+        self.var_decl_kind = old;
+
         VarDecl {
             kind: VarDeclKind::Var,
             ..var
@@ -344,7 +360,11 @@ impl Fold<VarDeclarator> for BlockScoping {
         let var = var.fold_children(self);
 
         let init = if self.in_loop_body() && var.init.is_none() {
-            Some(undefined(var.span()))
+            if self.var_decl_kind == VarDeclKind::Var {
+                None
+            } else {
+                Some(undefined(var.span()))
+            }
         } else {
             var.init
         };
@@ -419,6 +439,8 @@ struct InfectionFinder<'a> {
     found: bool,
 }
 
+noop_visit_type!(InfectionFinder<'_>);
+
 impl Visit<VarDeclarator> for InfectionFinder<'_> {
     fn visit(&mut self, node: &VarDeclarator) {
         let old = self.found;
@@ -480,6 +502,19 @@ impl Visit<Ident> for InfectionFinder<'_> {
     }
 }
 
+#[derive(Debug)]
+struct FunctionFinder {
+    found: bool,
+}
+
+noop_visit_type!(FunctionFinder);
+
+impl Visit<Function> for FunctionFinder {
+    fn visit(&mut self, node: &Function) {
+        self.found = true
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::block_scoping;
@@ -591,4 +626,52 @@ expect(functions[0]()).toBe(1);
 expect(functions[1]()).toBe(3);
 "
     );
+
+    test!(
+        ::swc_ecma_parser::Syntax::default(),
+        |_| block_scoping(),
+        issue_662,
+        "function foo(parts) {
+  let match = null;
+
+  for (let i = 1; i >= 0; i--) {
+    for (let j = 0; j >= 0; j--) {
+      match = parts[i][j];
+
+      if (match) {
+        break;
+      }
+    }
+
+    if (match) {
+      break;
+    }
+  }
+
+  return match;
+}
+
+foo();",
+        "function foo(parts) {
+  var match = null;
+
+  for (var i = 1; i >= 0; i--) {
+    for (var j = 0; j >= 0; j--) {
+      match = parts[i][j];
+
+      if (match) {
+        break;
+      }
+    }
+
+    if (match) {
+      break;
+    }
+  }
+
+  return match;
+}
+
+foo();"
+    );
 }

src/lib.rs

@@ -206,80 +206,83 @@ impl Compiler {
         opts: &Options,
         fm: &SourceFile,
     ) -> Result<BuiltConfig<impl Pass>, Error> {
-        let Options {
-            ref root,
-            root_mode,
-            swcrc,
-            config_file,
-            is_module,
-            ..
-        } = opts;
-        let root = root
-            .clone()
-            .unwrap_or_else(|| ::std::env::current_dir().unwrap());
+        self.run(|| {
+            let Options {
+                ref root,
+                root_mode,
+                swcrc,
+                config_file,
+                is_module,
+                ..
+            } = opts;
+            let root = root
+                .clone()
+                .unwrap_or_else(|| ::std::env::current_dir().unwrap());
 
-        let config_file = match config_file {
-            Some(ConfigFile::Str(ref s)) => {
-                let path = Path::new(s);
-                let r = File::open(&path).map_err(|err| Error::FailedToReadConfigFile { err })?;
-                let config: Rc = serde_json::from_reader(r)
-                    .map_err(|err| Error::FailedToParseConfigFile { err })?;
-                Some(config)
-            }
-            _ => None,
-        };
-
-        match fm.name {
-            FileName::Real(ref path) => {
-                if *swcrc {
-                    let mut parent = path.parent();
-                    while let Some(dir) = parent {
-                        let swcrc = dir.join(".swcrc");
-
-                        if swcrc.exists() {
-                            let r = File::open(&swcrc)
-                                .map_err(|err| Error::FailedToReadConfigFile { err })?;
-                            let mut config = serde_json::from_reader(r)
-                                .map_err(|err| Error::FailedToParseConfigFile { err })
-                                .and_then(|rc: Rc| rc.into_config(Some(path)))?;
-
-                            if let Some(config_file) = config_file {
-                                config.merge(&config_file.into_config(Some(path))?)
-                            }
-                            let built =
-                                opts.build(&self.cm, &self.handler, *is_module, Some(config));
-                            return Ok(built);
-                        }
-
-                        if dir == root && *root_mode == RootMode::Root {
-                            break;
-                        }
-                        parent = dir.parent();
-                    }
+            let config_file = match config_file {
+                Some(ConfigFile::Str(ref s)) => {
+                    let path = Path::new(s);
+                    let r =
+                        File::open(&path).map_err(|err| Error::FailedToReadConfigFile { err })?;
+                    let config: Rc = serde_json::from_reader(r)
+                        .map_err(|err| Error::FailedToParseConfigFile { err })?;
+                    Some(config)
                 }
+                _ => None,
+            };
 
-                let config_file = config_file.unwrap_or_else(|| Rc::default());
-                let built = opts.build(
-                    &self.cm,
-                    &self.handler,
-                    *is_module,
-                    Some(config_file.into_config(Some(path))?),
-                );
-                return Ok(built);
+            match fm.name {
+                FileName::Real(ref path) => {
+                    if *swcrc {
+                        let mut parent = path.parent();
+                        while let Some(dir) = parent {
+                            let swcrc = dir.join(".swcrc");
+
+                            if swcrc.exists() {
+                                let r = File::open(&swcrc)
+                                    .map_err(|err| Error::FailedToReadConfigFile { err })?;
+                                let mut config = serde_json::from_reader(r)
+                                    .map_err(|err| Error::FailedToParseConfigFile { err })
+                                    .and_then(|rc: Rc| rc.into_config(Some(path)))?;
+
+                                if let Some(config_file) = config_file {
+                                    config.merge(&config_file.into_config(Some(path))?)
+                                }
+                                let built =
+                                    opts.build(&self.cm, &self.handler, *is_module, Some(config));
+                                return Ok(built);
+                            }
+
+                            if dir == root && *root_mode == RootMode::Root {
+                                break;
+                            }
+                            parent = dir.parent();
+                        }
+                    }
+
+                    let config_file = config_file.unwrap_or_else(|| Rc::default());
+                    let built = opts.build(
+                        &self.cm,
+                        &self.handler,
+                        *is_module,
+                        Some(config_file.into_config(Some(path))?),
+                    );
+                    return Ok(built);
+                }
+                _ => {}
             }
-            _ => {}
-        }
 
-        let built = opts.build(
-            &self.cm,
-            &self.handler,
-            *is_module,
-            match config_file {
-                Some(config_file) => Some(config_file.into_config(None)?),
-                None => Some(Rc::default().into_config(None)?),
-            },
-        );
-        Ok(built)
+            let built = opts.build(
+                &self.cm,
+                &self.handler,
+                *is_module,
+                match config_file {
+                    Some(config_file) => Some(config_file.into_config(None)?),
+                    None => Some(Rc::default().into_config(None)?),
+                },
+            );
+            Ok(built)
+        })
     }
 
     pub fn process_js_file(