fix corner cases in collapse_vars (#4591)

fixes #4590

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);

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"
+}

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;

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,
     }

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: {