ensure `super()` is not merged with adjacent statements (#2757)

* ensure `super()` is not merged with adjacent statements

* add TODO

2 files changed, 18 insertions, 5 deletions

diff --git a/src/js_ast.zig b/src/js_ast.zig
index cd9f876bd..35fe6b6ec 100644
--- a/src/js_ast.zig
+++ b/src/js_ast.zig
@@ -2511,6 +2511,10 @@ pub const Stmt = struct {
         return @as(Stmt.Tag, self.data) == .s_type_script;
     }
 
+    pub fn isSuperCall(self: Stmt) bool {
+        return self.data == .s_expr and self.data.s_expr.value.data == .e_call and self.data.s_expr.value.data.e_call.target.data == .e_super;
+    }
+
     pub fn empty() Stmt {
         return Stmt{ .data = .{ .s_empty = None }, .loc = logger.Loc{} };
     }
diff --git a/src/js_parser.zig b/src/js_parser.zig
index abecc989c..3a35ed679 100644
--- a/src/js_parser.zig
+++ b/src/js_parser.zig
@@ -19154,6 +19154,9 @@ fn NewParser_(
 
                             constructor_function.?.func.body.stmts = constructor_stmts.items;
                         }
+
+                        // TODO: make sure "super()" comes before instance field initializers
+                        // https://github.com/evanw/esbuild/blob/e9413cc4f7ab87263ea244a999c6fa1f1e34dc65/internal/js_parser/js_parser_lower.go#L2742
                     }
 
                     var stmts_count: usize = 1 + static_members.items.len + instance_decorators.items.len + static_decorators.items.len;
@@ -20128,6 +20131,12 @@ fn NewParser_(
                         break;
                     }
 
+                    // don't merge super calls to ensure they are called before "this" is accessed
+                    if (stmt.isSuperCall()) {
+                        output.append(stmt) catch unreachable;
+                        continue;
+                    }
+
                     switch (stmt.data) {
                         .s_empty => continue,
 
@@ -20151,7 +20160,7 @@ fn NewParser_(
                             // Merge adjacent expression statements
                             if (output.items.len > 0) {
                                 var prev_stmt = &output.items[output.items.len - 1];
-                                if (prev_stmt.data == .s_expr) {
+                                if (prev_stmt.data == .s_expr and !prev_stmt.isSuperCall()) {
                                     prev_stmt.data.s_expr.does_not_affect_tree_shaking = prev_stmt.data.s_expr.does_not_affect_tree_shaking and
                                         s_expr.does_not_affect_tree_shaking;
                                     prev_stmt.data.s_expr.value = prev_stmt.data.s_expr.value.joinWithComma(
@@ -20166,7 +20175,7 @@ fn NewParser_(
                             // Absorb a previous expression statement
                             if (output.items.len > 0) {
                                 var prev_stmt = &output.items[output.items.len - 1];
-                                if (prev_stmt.data == .s_expr) {
+                                if (prev_stmt.data == .s_expr and !prev_stmt.isSuperCall()) {
                                     s_switch.test_ = prev_stmt.data.s_expr.value.joinWithComma(s_switch.test_, p.allocator);
                                     output.items.len -= 1;
                                 }
@@ -20176,7 +20185,7 @@ fn NewParser_(
                             // Absorb a previous expression statement
                             if (output.items.len > 0) {
                                 var prev_stmt = &output.items[output.items.len - 1];
-                                if (prev_stmt.data == .s_expr) {
+                                if (prev_stmt.data == .s_expr and !prev_stmt.isSuperCall()) {
                                     s_if.test_ = prev_stmt.data.s_expr.value.joinWithComma(s_if.test_, p.allocator);
                                     output.items.len -= 1;
                                 }
@@ -20189,7 +20198,7 @@ fn NewParser_(
                             // Merge return statements with the previous expression statement
                             if (output.items.len > 0 and ret.value != null) {
                                 var prev_stmt = &output.items[output.items.len - 1];
-                                if (prev_stmt.data == .s_expr) {
+                                if (prev_stmt.data == .s_expr and !prev_stmt.isSuperCall()) {
                                     ret.value = prev_stmt.data.s_expr.value.joinWithComma(ret.value.?, p.allocator);
                                     prev_stmt.* = stmt;
                                     continue;
@@ -20207,7 +20216,7 @@ fn NewParser_(
                             // Merge throw statements with the previous expression statement
                             if (output.items.len > 0) {
                                 var prev_stmt = &output.items[output.items.len - 1];
-                                if (prev_stmt.data == .s_expr) {
+                                if (prev_stmt.data == .s_expr and !prev_stmt.isSuperCall()) {
                                     prev_stmt.* = p.s(S.Throw{
                                         .value = prev_stmt.data.s_expr.value.joinWithComma(
                                             stmt.data.s_throw.value,