support `#__PURE__` in ESTree (#4879)

2 files changed, 27 insertions, 5 deletions

diff --git a/lib/mozilla-ast.js b/lib/mozilla-ast.js
index 028441b7..bfc6ac31 100644
--- a/lib/mozilla-ast.js
+++ b/lib/mozilla-ast.js
@@ -446,8 +446,22 @@
                 args.value = val;
                 return new AST_String(args);
               case "number":
-                args.value = val;
-                return new AST_Number(args);
+                if (isNaN(val)) return new AST_NaN(args);
+                var negate, node;
+                if (isFinite(val)) {
+                    negate = 1 / val < 0;
+                    args.value = negate ? -val : val;
+                    node = new AST_Number(args);
+                } else {
+                    negate = val < 0;
+                    node = new AST_Infinity(args);
+                }
+                return negate ? new AST_UnaryPrefix({
+                    start: args.start,
+                    end: args.end,
+                    operator: "-",
+                    expression: node,
+                }) : node;
               case "boolean":
                 return new (val ? AST_True : AST_False)(args);
             }
@@ -532,6 +546,14 @@
                 name: "this",
             });
         },
+        ParenthesizedExpression: function(M) {
+            var node = from_moz(M.expression);
+            if (!node.start.parens) node.start.parens = [];
+            node.start.parens.push(my_start_token(M));
+            if (!node.end.parens) node.end.parens = [];
+            node.end.parens.push(my_end_token(M));
+            return node;
+        },
     };
 
     MOZ_TO_ME.UpdateExpression =
@@ -570,8 +592,8 @@
     map("AssignmentExpression", AST_Assign, "operator=operator, left>left, right>right");
     map("AssignmentPattern", AST_DefaultValue, "left>name, right>value");
     map("ConditionalExpression", AST_Conditional, "test>condition, consequent>consequent, alternate>alternative");
-    map("NewExpression", AST_New, "callee>expression, arguments@args");
-    map("CallExpression", AST_Call, "callee>expression, arguments@args");
+    map("NewExpression", AST_New, "callee>expression, arguments@args, pure=pure");
+    map("CallExpression", AST_Call, "callee>expression, arguments@args, pure=pure");
     map("SequenceExpression", AST_Sequence, "expressions@expressions");
     map("SpreadElement", AST_Spread, "argument>expression");
     map("ObjectExpression", AST_Object, "properties@properties");
diff --git a/lib/output.js b/lib/output.js
index 43512606..75ccca2d 100644
--- a/lib/output.js
+++ b/lib/output.js
@@ -1456,7 +1456,7 @@ function OutputStream(options) {
             parent = output.parent(level++);
             if (parent instanceof AST_Call && parent.expression === node) return;
         } while (parent instanceof AST_PropAccess && parent.expression === node);
-        output.print("/*" + self.pure + "*/");
+        output.print(typeof self.pure == "string" ? "/*" + self.pure + "*/" : "/*@__PURE__*/");
     }
     function print_call_args(self, output) {
         if (self.expression instanceof AST_Call || self.expression instanceof AST_Lambda) {