diff --git a/lib/compress.js b/lib/compress.js
index bcfee5a4..c421525e 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -6841,6 +6841,7 @@ Compressor.prototype.compress = function(node) {
         if (self instanceof AST_Toplevel && compressor.top_retain) {
             self.variables.each(function(def) {
                 if (compressor.top_retain(def) && !(def.id in in_use_ids)) {
+                    AST_Node.info("Retaining variable {name}", def);
                     in_use_ids[def.id] = true;
                     in_use.push(def);
                 }
diff --git a/lib/propmangle.js b/lib/propmangle.js
index cf5e3781..f034a091 100644
--- a/lib/propmangle.js
+++ b/lib/propmangle.js
@@ -260,8 +260,14 @@ function mangle_properties(ast, options) {
     }
 
     function should_mangle(name) {
-        if (reserved.has(name)) return false;
-        if (regex && !regex.test(name)) return false;
+        if (reserved.has(name)) {
+            AST_Node.info("Preserving reserved property {this}", name);
+            return false;
+        }
+        if (regex && !regex.test(name)) {
+            AST_Node.info("Preserving excluded property {this}", name);
+            return false;
+        }
         return cache.has(name) || names_to_mangle.has(name);
     }
 
@@ -271,10 +277,7 @@ function mangle_properties(ast, options) {
     }
 
     function mangle(name) {
-        if (!should_mangle(name)) {
-            AST_Node.info("Preserving property {this}", name);
-            return name;
-        }
+        if (!should_mangle(name)) return name;
         var mangled = cache.get(name);
         if (!mangled) {
             if (debug) {
diff --git a/test/compress/classes.js b/test/compress/classes.js
index 39e26631..32c4d74e 100644
--- a/test/compress/classes.js
+++ b/test/compress/classes.js
@@ -2201,12 +2201,12 @@ mangle_properties: {
     }
     expect_stdout: "PASS 42"
     expect_warnings: [
+        "INFO: Preserving reserved property q",
+        "INFO: Preserving reserved property log",
         "INFO: Mapping property #P to #t",
         "INFO: Mapping property Q to s",
         "INFO: Mapping property #p to #i",
         "INFO: Mapping property r to e",
-        "INFO: Preserving property q",
-        "INFO: Preserving property log",
     ]
     node_version: ">=14.6"
 }
diff --git a/test/compress/drop-unused.js b/test/compress/drop-unused.js
index d34b2bd9..1f4d2c92 100644
--- a/test/compress/drop-unused.js
+++ b/test/compress/drop-unused.js
@@ -409,6 +409,15 @@ drop_toplevel_retain: {
         a = 2;
         console.log(3);
     }
+    expect_stdout: "3"
+    expect_warnings: [
+        "INFO: Retaining variable a",
+        "INFO: Retaining variable f",
+        "INFO: Dropping unused variable b [test/compress/drop-unused.js:1,15]",
+        "INFO: Dropping unused variable c [test/compress/drop-unused.js:1,22]",
+        "INFO: Dropping unused function g [test/compress/drop-unused.js:8,17]",
+        "WARN: Dropping unused function h [test/compress/drop-unused.js:9,17]",
+    ]
 }
 
 drop_toplevel_retain_array: {
@@ -442,6 +451,15 @@ drop_toplevel_retain_array: {
         a = 2;
         console.log(3);
     }
+    expect_stdout: "3"
+    expect_warnings: [
+        "INFO: Retaining variable a",
+        "INFO: Retaining variable f",
+        "INFO: Dropping unused variable b [test/compress/drop-unused.js:1,15]",
+        "INFO: Dropping unused variable c [test/compress/drop-unused.js:1,22]",
+        "INFO: Dropping unused function g [test/compress/drop-unused.js:8,17]",
+        "WARN: Dropping unused function h [test/compress/drop-unused.js:9,17]",
+    ]
 }
 
 drop_toplevel_retain_regex: {
@@ -471,6 +489,15 @@ drop_toplevel_retain_regex: {
         a = 2;
         console.log(3);
     }
+    expect_stdout: "3"
+    expect_warnings: [
+        "INFO: Retaining variable a",
+        "INFO: Retaining variable f",
+        "INFO: Dropping unused variable b [test/compress/drop-unused.js:1,15]",
+        "INFO: Dropping unused variable c [test/compress/drop-unused.js:1,22]",
+        "INFO: Dropping unused function g [test/compress/drop-unused.js:8,17]",
+        "WARN: Dropping unused function h [test/compress/drop-unused.js:9,17]",
+    ]
 }
 
 drop_toplevel_all_retain: {
@@ -501,6 +528,15 @@ drop_toplevel_all_retain: {
         a = 2;
         console.log(3);
     }
+    expect_stdout: "3"
+    expect_warnings: [
+        "INFO: Retaining variable a",
+        "INFO: Retaining variable f",
+        "INFO: Dropping unused variable b [test/compress/drop-unused.js:1,15]",
+        "INFO: Dropping unused variable c [test/compress/drop-unused.js:1,22]",
+        "INFO: Dropping unused function g [test/compress/drop-unused.js:8,17]",
+        "WARN: Dropping unused function h [test/compress/drop-unused.js:9,17]",
+    ]
 }
 
 drop_toplevel_funcs_retain: {
@@ -532,6 +568,12 @@ drop_toplevel_funcs_retain: {
         function g() {}
         console.log(b = 3);
     }
+    expect_stdout: "3"
+    expect_warnings: [
+        "INFO: Retaining variable a",
+        "INFO: Retaining variable f",
+        "WARN: Dropping unused function h [test/compress/drop-unused.js:9,17]",
+    ]
 }
 
 drop_toplevel_vars_retain: {
@@ -564,6 +606,13 @@ drop_toplevel_vars_retain: {
         function h() {}
         console.log(3);
     }
+    expect_stdout: "3"
+    expect_warnings: [
+        "INFO: Retaining variable a",
+        "INFO: Retaining variable f",
+        "INFO: Dropping unused variable b [test/compress/drop-unused.js:1,15]",
+        "INFO: Dropping unused variable c [test/compress/drop-unused.js:1,22]",
+    ]
 }
 
 drop_toplevel_keep_assign: {
diff --git a/test/compress/hoist_props.js b/test/compress/hoist_props.js
index b3c93f7d..35d9127b 100644
--- a/test/compress/hoist_props.js
+++ b/test/compress/hoist_props.js
@@ -462,6 +462,11 @@ issue_2473_1: {
         var x = {};
         var y = [];
     }
+    expect_warnings: [
+        "INFO: Retaining variable x",
+        "INFO: Retaining variable y",
+        "WARN: Dropping unused variable z [test/compress/hoist_props.js:3,12]",
+    ]
 }
 
 issue_2473_2: {
@@ -484,6 +489,11 @@ issue_2473_2: {
         var x = {};
         var y = [];
     }
+    expect_warnings: [
+        "INFO: Retaining variable x",
+        "INFO: Retaining variable y",
+        "WARN: Dropping unused variable z [test/compress/hoist_props.js:3,12]",
+    ]
 }
 
 issue_2473_3: {
@@ -509,6 +519,9 @@ issue_2473_3: {
         console.log(o.a, o.b);
     }
     expect_stdout: "1 2"
+    expect_warnings: [
+        "INFO: Retaining variable o",
+    ]
 }
 
 issue_2473_4: {
@@ -535,6 +548,9 @@ issue_2473_4: {
         })();
     }
     expect_stdout: "1 2"
+    expect_warnings: [
+        "INFO: Dropping unused variable o [test/compress/hoist_props.js:2,16]",
+    ]
 }
 
 issue_2508_1: {
diff --git a/test/compress/issue-1770.js b/test/compress/issue-1770.js
index 3b2f8cba..ad8b22a2 100644
--- a/test/compress/issue-1770.js
+++ b/test/compress/issue-1770.js
@@ -53,6 +53,14 @@ mangle_props: {
         );
     }
     expect_stdout: "1 1 1 2 2 2 3 3 3 4 4 4 5 5"
+    expect_warnings: [
+        "INFO: Preserving reserved property undefined",
+        "INFO: Preserving reserved property NaN",
+        "INFO: Preserving reserved property Infinity",
+        "INFO: Preserving reserved property -Infinity",
+        "INFO: Preserving reserved property null",
+        "INFO: Preserving reserved property log",
+    ]
 }
 
 numeric_literal: {
@@ -106,6 +114,11 @@ numeric_literal: {
         "4 5 4 4",
         "8 7 8",
     ]
+    expect_warnings: [
+        "INFO: Preserving reserved property log",
+        "INFO: Mapping property 0x25 to o",
+        "INFO: Mapping property 1E42 to b",
+    ]
 }
 
 identifier: {
diff --git a/test/compress/issue-747.js b/test/compress/issue-747.js
index e074305a..8d5289bb 100644
--- a/test/compress/issue-747.js
+++ b/test/compress/issue-747.js
@@ -19,6 +19,11 @@ dont_reuse_prop: {
         console.log(obj.a);
     }
     expect_stdout: "123"
+    expect_warnings: [
+        "INFO: Preserving excluded property a",
+        "INFO: Preserving reserved property log",
+        "INFO: Mapping property asd to b",
+    ]
 }
 
 unmangleable_props_should_always_be_reserved: {
@@ -42,4 +47,9 @@ unmangleable_props_should_always_be_reserved: {
         console.log(obj.a);
     }
     expect_stdout: "123"
+    expect_warnings: [
+        "INFO: Preserving excluded property a",
+        "INFO: Preserving reserved property log",
+        "INFO: Mapping property asd to b",
+    ]
 }