From ba4a771bbccb0b6026588a56b0c31f5bac466775 Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Fri, 26 Feb 2021 20:56:34 +0000
Subject: support limited `ufuzz` testing for `export` (#4693)

fixes #4692
---
 lib/ast.js      | 10 +---------
 lib/compress.js | 12 +++++++++---
 lib/output.js   | 19 +++++++++++++++----
 3 files changed, 25 insertions(+), 16 deletions(-)

(limited to 'lib')

diff --git a/lib/ast.js b/lib/ast.js
index 3c6672c2..5fe6efc1 100644
--- a/lib/ast.js
+++ b/lib/ast.js
@@ -1176,15 +1176,7 @@ var AST_ExportDefault = DEFNODE("ExportDefault", "body", {
         });
     },
     _validate: function() {
-        if (this.body instanceof AST_Class && this.body.name) {
-            if (!(this.body instanceof AST_DefClass)) {
-                throw new Error("body must be AST_DefClass when named");
-            }
-        } else if (this.body instanceof AST_Lambda && this.body.name) {
-            if (!(this.body instanceof AST_LambdaDefinition)) {
-                throw new Error("body must be AST_LambdaDefinition when named");
-            }
-        } else {
+        if (!(this.body instanceof AST_DefClass || this.body instanceof AST_LambdaDefinition)) {
             must_be_expression(this, "body");
         }
     },
diff --git a/lib/compress.js b/lib/compress.js
index 0e698804..101fdb4e 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -940,6 +940,8 @@ merge(Compressor.prototype, {
             });
             if (!node.name) return;
             var d = node.name.definition();
+            var parent = tw.parent();
+            if (parent instanceof AST_ExportDeclaration || parent instanceof AST_ExportDefault) d.single_use = false;
             if (safe_to_assign(tw, d, true)) {
                 mark(tw, d);
                 tw.loop_ids[d.id] = tw.in_loop;
@@ -6709,6 +6711,7 @@ merge(Compressor.prototype, {
             var var_decl = 0;
             self.walk(new TreeWalker(function(node) {
                 if (var_decl > 1) return true;
+                if (node instanceof AST_ExportDeclaration) return true;
                 if (node instanceof AST_Scope && node !== self) return true;
                 if (node instanceof AST_Var) {
                     var_decl++;
@@ -6728,12 +6731,15 @@ merge(Compressor.prototype, {
                 dirs.push(node);
                 return make_node(AST_EmptyStatement, node);
             }
-            if (hoist_funs && node instanceof AST_Defun
-                && (tt.parent() === self || !compressor.has_directive("use strict"))) {
+            if (node instanceof AST_Defun) {
+                if (!hoist_funs) return node;
+                if (tt.parent() !== self && compressor.has_directive("use strict")) return node;
                 hoisted.push(node);
                 return make_node(AST_EmptyStatement, node);
             }
-            if (hoist_vars && node instanceof AST_Var) {
+            if (node instanceof AST_Var) {
+                if (!hoist_vars) return node;
+                if (tt.parent() instanceof AST_ExportDeclaration) return node;
                 if (!all(node.definitions, function(defn) {
                     var sym = defn.name;
                     return sym instanceof AST_SymbolVar
diff --git a/lib/output.js b/lib/output.js
index 49164359..bebcd7fd 100644
--- a/lib/output.js
+++ b/lib/output.js
@@ -664,7 +664,9 @@ function OutputStream(options) {
     function needs_parens_function(output) {
         if (!output.has_parens() && first_in_statement(output)) return true;
         var p = output.parent();
-        // export default (function() {})()
+        // export default (function foo() {});
+        if (this.name && p instanceof AST_ExportDefault) return true;
+        // export default (function() {})(foo);
         if (p && p.TYPE == "Call" && output.parent(1) instanceof AST_ExportDefault) return true;
         if (output.option("webkit") && p instanceof AST_PropAccess && p.expression === this) return true;
         if (output.option("wrap_iife") && p instanceof AST_Call && p.expression === this) return true;
@@ -725,6 +727,8 @@ function OutputStream(options) {
             // { [(1, 2)]: foo } = bar
             // { 1: (2, foo) } = bar
             || p instanceof AST_DestructuredKeyVal
+            // export default (foo, bar)
+            || p instanceof AST_ExportDefault
             // for (foo of (bar, baz));
             || p instanceof AST_ForOf
             // { [(1, 2)]: 3 }[2] ---> 3
@@ -1032,9 +1036,16 @@ function OutputStream(options) {
         output.space();
         output.print("default");
         output.space();
-        this.body.print(output);
-        if (this.body instanceof AST_Class) return;
-        if (this.body instanceof AST_Lambda && !is_arrow(this.body)) return;
+        var body = this.body;
+        body.print(output);
+        if (body instanceof AST_ClassExpression) {
+            if (!body.name) return;
+        }
+        if (body instanceof AST_DefClass) return;
+        if (body instanceof AST_LambdaDefinition) return;
+        if (body instanceof AST_LambdaExpression) {
+            if (!body.name && !is_arrow(body)) return;
+        }
         output.semicolon();
     });
     DEFPRINT(AST_ExportForeign, function(output) {
-- 
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