From fd7ad8e7792749c29dec2038bb6cc61cbb7721f1 Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Sun, 24 Jan 2021 14:15:43 +0000
Subject: [PATCH] fix corner cases in `collapse_vars` (#4591)

fixes #4590
---
 lib/compress.js                |  6 ++++--
 test/compress/bigint.js        | 16 ++++++++++++++++
 test/compress/collapse_vars.js |  5 +++++
 test/compress/drop-unused.js   |  3 +++
 test/compress/pure_getters.js  |  4 ++++
 5 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/lib/compress.js b/lib/compress.js
index e5ee7406..d79c1cce 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -2413,7 +2413,8 @@ merge(Compressor.prototype, {
                 if (expr instanceof AST_This) return rhs_exact_match;
                 if (expr.is_truthy()) return rhs_fuzzy_match(true, return_false);
                 if (expr.is_constant()) {
-                    return rhs_fuzzy_match(expr.evaluate(compressor), rhs_exact_match);
+                    var ev = expr.evaluate(compressor);
+                    if (!(ev instanceof AST_Node)) return rhs_fuzzy_match(ev, rhs_exact_match);
                 }
                 if (!(lhs instanceof AST_SymbolRef)) return false;
                 if (!invariant(expr)) return false;
@@ -2436,7 +2437,8 @@ merge(Compressor.prototype, {
                             return true;
                         }
                         if (node.is_constant()) {
-                            return !node.evaluate(compressor) == !value;
+                            var ev = node.evaluate(compressor);
+                            if (!(ev instanceof AST_Node)) return !ev == !value;
                         }
                     }
                     return fallback(node);
diff --git a/test/compress/bigint.js b/test/compress/bigint.js
index 7ee225ce..9c21d083 100644
--- a/test/compress/bigint.js
+++ b/test/compress/bigint.js
@@ -44,3 +44,19 @@ Number: {
     expect_stdout: "-1148098955808013200"
     node_version: ">=10"
 }
+
+issue_4590: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        A = 1;
+        0n || console.log("PASS");
+    }
+    expect: {
+        A = 1;
+        0n || console.log("PASS");
+    }
+    expect_stdout: "PASS"
+    node_version: ">=10"
+}
diff --git a/test/compress/collapse_vars.js b/test/compress/collapse_vars.js
index 963906c5..04df8e11 100644
--- a/test/compress/collapse_vars.js
+++ b/test/compress/collapse_vars.js
@@ -5608,6 +5608,7 @@ collapse_rhs_array: {
 collapse_rhs_boolean_1: {
     options = {
         collapse_vars: true,
+        evaluate: true,
     }
     input: {
         var a, b;
@@ -5633,6 +5634,7 @@ collapse_rhs_boolean_1: {
 collapse_rhs_boolean_2: {
     options = {
         collapse_vars: true,
+        evaluate: true,
     }
     input: {
         var a;
@@ -5667,6 +5669,7 @@ collapse_rhs_boolean_3: {
         booleans: true,
         collapse_vars: true,
         conditionals: true,
+        evaluate: true,
     }
     input: {
         var a, f, g, h, i, n, s, t, x, y;
@@ -5720,6 +5723,7 @@ collapse_rhs_function: {
 collapse_rhs_number: {
     options = {
         collapse_vars: true,
+        evaluate: true,
     }
     input: {
         var a, b;
@@ -5799,6 +5803,7 @@ collapse_rhs_regexp: {
 collapse_rhs_string: {
     options = {
         collapse_vars: true,
+        evaluate: true,
     }
     input: {
         var a, b;
diff --git a/test/compress/drop-unused.js b/test/compress/drop-unused.js
index d00deca2..914e83ad 100644
--- a/test/compress/drop-unused.js
+++ b/test/compress/drop-unused.js
@@ -2138,6 +2138,7 @@ issue_3497: {
 issue_3515_1: {
     options = {
         collapse_vars: true,
+        evaluate: true,
         reduce_vars: true,
         unused: true,
     }
@@ -2189,6 +2190,7 @@ issue_3515_2: {
 issue_3515_3: {
     options = {
         collapse_vars: true,
+        evaluate: true,
         unused: true,
     }
     input: {
@@ -2256,6 +2258,7 @@ function_assign: {
 issue_3598: {
     options = {
         collapse_vars: true,
+        evaluate: true,
         reduce_vars: true,
         unused: true,
     }
diff --git a/test/compress/pure_getters.js b/test/compress/pure_getters.js
index 1cb2ff13..58920411 100644
--- a/test/compress/pure_getters.js
+++ b/test/compress/pure_getters.js
@@ -979,6 +979,7 @@ collapse_vars_2_strict: {
 collapse_rhs_true: {
     options = {
         collapse_vars: true,
+        evaluate: true,
         pure_getters: true,
     }
     input: {
@@ -1015,6 +1016,7 @@ collapse_rhs_true: {
 collapse_rhs_false: {
     options = {
         collapse_vars: true,
+        evaluate: true,
         pure_getters: false,
     }
     input: {
@@ -1051,6 +1053,7 @@ collapse_rhs_false: {
 collapse_rhs_strict: {
     options = {
         collapse_vars: true,
+        evaluate: true,
         pure_getters: "strict",
     }
     input: {
@@ -1087,6 +1090,7 @@ collapse_rhs_strict: {
 collapse_rhs_setter: {
     options = {
         collapse_vars: true,
+        evaluate: true,
         pure_getters: "strict",
     }
     input: {