diff --git a/.php-cs-fixer.dist.php b/.php-cs-fixer.dist.php
index 841e41e..7571f30 100644
--- a/.php-cs-fixer.dist.php
+++ b/.php-cs-fixer.dist.php
@@ -13,12 +13,16 @@
 ]);
 
 return (new Config())
+    ->setRiskyAllowed(true)
     ->setParallelConfig(ParallelConfigFactory::detect())
     ->setRules([
         '@PER-CS3.0' => true,
         'no_unused_imports' => true,
         'ordered_class_elements' => true,
         'class_attributes_separation' => ['elements' => ['method' => 'one']],
+        'declare_strict_types' => true,
+        'native_function_invocation' => true,
+        'native_constant_invocation' => true,
         'fully_qualified_strict_types' => [
             'import_symbols' => true
         ],
diff --git a/CHANGELOG.md b/CHANGELOG.md
index d420add..07186de 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 ## 3.1.2 under development
 
 - Bug #87: Fix PHPDoc tags `@see` (@mspirkov)
+- Enh #89: Explicitly import functions in "use" section (@mspirkov)
 
 ## 3.1.1 December 04, 2025
 
diff --git a/src/Aliases.php b/src/Aliases.php
index 735ce9e..850f843 100644
--- a/src/Aliases.php
+++ b/src/Aliases.php
@@ -9,6 +9,7 @@
 use function array_key_exists;
 use function is_array;
 use function is_string;
+use function strlen;
 
 final class Aliases
 {
diff --git a/tests/AliasesTest.php b/tests/AliasesTest.php
index 5e24b85..a5bd99f 100644
--- a/tests/AliasesTest.php
+++ b/tests/AliasesTest.php
@@ -9,6 +9,8 @@
 use PHPUnit\Framework\TestCase;
 use Yiisoft\Aliases\Aliases;
 
+use function sprintf;
+
 final class AliasesTest extends TestCase
 {
     public function testNonAlias(): void
diff --git a/tests/ConfigTest.php b/tests/ConfigTest.php
index aa814db..ec91c3c 100644
--- a/tests/ConfigTest.php
+++ b/tests/ConfigTest.php
@@ -9,6 +9,8 @@
 use Yiisoft\Di\Container;
 use Yiisoft\Di\ContainerConfig;
 
+use function dirname;
+
 final class ConfigTest extends TestCase
 {
     public function testBase(): void