fix bug with incorrectly emitted modules

lib/optimize/SideEffectsFlagPlugin.js

@@ -107,7 +107,10 @@ class SideEffectsFlagPlugin {
 						const map = pair[1];
 						for (const reason of module.reasons) {
 							const dep = reason.dependency;
-							if (dep instanceof HarmonyImportSpecifierDependency) {
+							if (
+								dep instanceof HarmonyImportSpecifierDependency &&
+								!dep.namespaceObjectAsContext
+							) {
 								const mapping = map.get(dep.id);
 								if (mapping) {
 									dep.redirectedModule = mapping.module;

test/__snapshots__/StatsTestCases.test.js.snap

@@ -2062,6 +2062,25 @@ Child
         ModuleConcatenation bailout: Module is referenced from these modules with unsupported syntax: ./first.js (referenced with import())"
 `;
 
+exports[`StatsTestCases should print correct stats for side-effects-simple-unused 1`] = `
+"Hash: 0cb74fac5f3c1b7f2150
+Time: Xms
+Built at: Thu Jan 01 1970 00:00:00 GMT
+  Asset      Size  Chunks             Chunk Names
+main.js  2.94 KiB       0  [emitted]  main
+Entrypoint main = main.js
+[0] ./node_modules/pmodule/b.js 69 bytes [built]
+    [no exports used]
+[1] ./node_modules/pmodule/a.js 60 bytes [built]
+    [no exports used]
+[2] ./index.js + 2 modules 158 bytes {0} [built]
+    | ./index.js 55 bytes [built]
+    | ./node_modules/pmodule/index.js 75 bytes [built]
+    |     [only some exports used: default]
+    | ./node_modules/pmodule/c.js 28 bytes [built]
+    |     [only some exports used: z]"
+`;
+
 exports[`StatsTestCases should print correct stats for simple 1`] = `
 "Hash: 1843cc9aed8366594774
 Time: Xms

test/statsCases/side-effects-simple-unused/index.js

@@ -0,0 +1,3 @@
+import def, { z } from "pmodule";
+
+console.log(def, z);

test/statsCases/side-effects-simple-unused/node_modules/pmodule/a.js

@@ -0,0 +1,5 @@
+var a = "a";
+var b = "b";
+var c = "c";
+
+export { a, b, c };

test/statsCases/side-effects-simple-unused/node_modules/pmodule/b.js

@@ -0,0 +1,5 @@
+var x = "x";
+var y = "y";
+
+export { x, y };
+export { z } from "./c";

test/statsCases/side-effects-simple-unused/node_modules/pmodule/c.js

@@ -0,0 +1,3 @@
+var z = "z";
+
+export { z };

test/statsCases/side-effects-simple-unused/node_modules/pmodule/index.js

@@ -0,0 +1,4 @@
+export * from "./a";
+export { x, y, z } from "./b";
+
+export default "def";

test/statsCases/side-effects-simple-unused/node_modules/pmodule/package.json

@@ -0,0 +1,3 @@
+{
+    "sideEffects": false
+}

test/statsCases/side-effects-simple-unused/webpack.config.js

@@ -0,0 +1,8 @@
+module.exports = {
+	mode: "production",
+	entry: "./index",
+	stats: {
+		nestedModules: true,
+		usedExports: true
+	}
+};