refactor(es/parser): Simplify parsing logic (#2405)

Cargo.lock

@@ -75,9 +75,9 @@ checksum = "f26201604c87b1e01bd3d98f8d5d9a8fcbb815e8cedb41ffccbeb4bf593a35fe"
 
 [[package]]
 name = "ahash"
-version = "0.7.4"
+version = "0.7.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "43bb833f0bf979d8475d38fbf09ed3b8a55e1885fe93ad3f93239fc6a4f17b98"
+checksum = "991984e3fd003e7ba02eb724f87a0f997b78677c46c0e91f8424ad7394c9886a"
 dependencies = [
  "const-random",
  "getrandom 0.2.3",
@@ -2411,7 +2411,7 @@ dependencies = [
 
 [[package]]
 name = "swc_bundler"
-version = "0.68.0"
+version = "0.68.1"
 dependencies = [
  "ahash",
  "anyhow",
@@ -2689,7 +2689,7 @@ dependencies = [
 
 [[package]]
 name = "swc_ecma_parser"
-version = "0.73.8"
+version = "0.73.9"
 dependencies = [
  "either",
  "enum_kind",
@@ -2974,7 +2974,7 @@ dependencies = [
 
 [[package]]
 name = "swc_ecma_utils"
-version = "0.47.0"
+version = "0.47.1"
 dependencies = [
  "once_cell",
  "rayon",

bundler/Cargo.toml

@@ -9,7 +9,7 @@ include = ["Cargo.toml", "build.rs", "src/**/*.rs", "src/**/*.js"]
 license = "Apache-2.0/MIT"
 name = "swc_bundler"
 repository = "https://github.com/swc-project/swc.git"
-version = "0.68.0"
+version = "0.68.1"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 [features]

ecmascript/parser/Cargo.toml

@@ -7,7 +7,7 @@ include = ["Cargo.toml", "src/**/*.rs", "examples/**/*.rs"]
 license = "Apache-2.0/MIT"
 name = "swc_ecma_parser"
 repository = "https://github.com/swc-project/swc.git"
-version = "0.73.8"
+version = "0.73.9"
 
 [package.metadata.docs.rs]
 all-features = true

ecmascript/parser/src/parser/expr.rs

@@ -1271,27 +1271,18 @@ impl<'a, I: Tokens> Parser<I> {
 
         expect!(self, '(');
 
-        let mut first = true;
         let mut items = vec![];
         let mut rest_span = None;
 
         // TODO(kdy1): optimize (once we parsed a pattern, we can parse everything else
         // as a pattern instead of reparsing)
         while !eof!(self) && !is!(self, ')') {
-            let mut is_async = false;
-
-            if first {
-                if is!(self, "async")
-                    && matches!(
-                        peek!(self),
-                        Ok(tok!('(') | tok!("function") | Token::Word(..))
-                    )
-                {
-                    // https://github.com/swc-project/swc/issues/410
-                    self.state.potential_arrow_start = Some(cur_pos!(self));
-                    is_async = true;
-                }
-            }
+            // https://github.com/swc-project/swc/issues/410
+            let is_async = is!(self, "async")
+                && matches!(
+                    peek!(self),
+                    Ok(tok!('(') | tok!("function") | Token::Word(..))
+                );
 
             let start = cur_pos!(self);
             self.state.potential_arrow_start = Some(start);
@@ -1495,7 +1486,7 @@ impl<'a, I: Tokens> Parser<I> {
             }
 
             // https://github.com/swc-project/swc/issues/433
-            if first && eat!(self, "=>") && {
+            if eat!(self, "=>") && {
                 debug_assert_eq!(items.len(), 1);
                 match items[0] {
                     PatOrExprOrSpread::ExprOrSpread(ExprOrSpread { ref expr, .. })
@@ -1532,8 +1523,6 @@ impl<'a, I: Tokens> Parser<I> {
                 }));
             }
 
-            first = true;
-
             if !is!(self, ')') {
                 expect!(self, ',');
             }

ecmascript/utils/Cargo.toml

@@ -6,7 +6,7 @@ edition = "2018"
 license = "Apache-2.0/MIT"
 name = "swc_ecma_utils"
 repository = "https://github.com/swc-project/swc.git"
-version = "0.47.0"
+version = "0.47.1"
 
 [features]
 # Process in parallel.