Check that import is preceeded by whitespace in plain case

lex.h

@@ -333,22 +333,25 @@ bare_module_lexer__lex (js_env_t *env, js_value_t *imports, js_value_t *exports,
         }
       }
 
-      else {
-        while (i < n && ws(u(0))) i++;
+      // import\s
+      else if (ws(c(-1))) {
+        size_t j = i;
 
-        // import [^\s]+
         while (i < n && !ws(u(0))) i++;
 
-        while (i < n && ws(u(0))) i++;
+        // import [^\s]+
+        if (j < i) {
+          while (i < n && ws(u(0))) i++;
 
-        // import [^\s]+ from
-        if (bc("from", 4)) {
-          i += 4;
+          // import [^\s]+ from
+          if (bc("from", 4)) {
+            i += 4;
 
-          err = bare_module_lexer__add_name(env, &names, &nl, (const utf8_t *) "default");
-          assert(err == 0);
+            err = bare_module_lexer__add_name(env, &names, &nl, (const utf8_t *) "default");
+            assert(err == 0);
 
-          goto from;
+            goto from;
+          }
         }
       }
     }

test.js

@@ -227,3 +227,17 @@ test('// require(\'id\')', (t) => {
     exports: []
   })
 })
+
+test('invalid require', (t) => {
+  t.alike(lex('requires(\'./foo.js\')'), {
+    imports: [],
+    exports: []
+  })
+})
+
+test('invalid import', (t) => {
+  t.alike(lex('imported from \'./foo.js\''), {
+    imports: [],
+    exports: []
+  })
+})