repl: give repl entries unique names.

This is a workaround for the REPL for a problem when multiple of the
entries have the same source text

Fixes: nodejs#1337
Refs: https://bugs.chromium.org/p/v8/issues/detail?id=10284

lib/repl.js

@@ -128,6 +128,10 @@ const {
 } = internalBinding('contextify');
 
 const history = require('internal/repl/history');
+let nextREPLResourceNumber = 1;
+function getREPLResourceName() {
+  return `REPL${nextREPLResourceNumber++}`;
+}
 
 // Lazy-loaded.
 let processTopLevelAwait;
@@ -767,7 +771,7 @@ function REPLServer(prompt,
     const evalCmd = self[kBufferedCommandSymbol] + cmd + '\n';
 
     debug('eval %j', evalCmd);
-    self.eval(evalCmd, self.context, 'repl', finish);
+    self.eval(evalCmd, self.context, getREPLResourceName(), finish);
 
     function finish(e, ret) {
       debug('finish', e, ret);
@@ -1248,7 +1252,7 @@ function complete(line, callback) {
 
     const memberGroups = [];
     const evalExpr = `try { ${expr} } catch {}`;
-    this.eval(evalExpr, this.context, 'repl', (e, obj) => {
+    this.eval(evalExpr, this.context, getREPLResourceName(), (e, obj) => {
       try {
         let p;
         if ((typeof obj === 'object' && obj !== null) ||

test/parallel/test-repl-dynamic-import.js

@@ -0,0 +1,20 @@
+'use strict';
+require('../common');
+const assert = require('assert');
+const child_process = require('child_process');
+const child = child_process.spawn(process.execPath, [
+  '--interactive',
+  '--expose-gc'
+], {
+  stdio: 'pipe'
+});
+child.stdin.write('\nimport("fs");\n_.then(gc);\n');
+// Wait for concurrent GC to finish
+setTimeout(() => {
+  child.stdin.write('\nimport("fs");\n');
+  child.stdin.write('\nprocess.exit(0);\n');
+}, 500);
+child.on('exit', (code, signal) => {
+  assert.strictEqual(code, 0);
+  assert.strictEqual(signal, null);
+});