[5.4] Move "tap" method to BuildsQueries trait.

src/Illuminate/Database/Concerns/BuildsQueries.php

@@ -94,6 +94,17 @@ public function when($value, $callback, $default = null)
         return $this;
     }
 
+    /**
+     * Pass the query to a given callback.
+     *
+     * @param  \Closure  $callback
+     * @return \Illuminate\Database\Query\Builder
+     */
+    public function tap($callback)
+    {
+        return $this->when(true, $callback);
+    }
+
     /**
      * Apply the callback's query changes if the given "value" is false.
      *

src/Illuminate/Database/Query/Builder.php

@@ -459,17 +459,6 @@ public function crossJoin($table, $first = null, $operator = null, $second = nul
         return $this;
     }
 
-    /**
-     * Pass the query to a given callback.
-     *
-     * @param  \Closure  $callback
-     * @return \Illuminate\Database\Query\Builder
-     */
-    public function tap($callback)
-    {
-        return $this->when(true, $callback);
-    }
-
     /**
      * Merge an array of where clauses and bindings.
      *

tests/Database/DatabaseConcernsBuildsQueriesTraitTest.php

@@ -0,0 +1,17 @@
+<?php
+
+namespace Illuminate\Tests\Database;
+
+use PHPUnit\Framework\TestCase;
+use Illuminate\Database\Concerns\BuildsQueries;
+
+class DatabaseConcernsBuildsQueriesTraitTest extends TestCase
+{
+    public function testTapCallbackInstance()
+    {
+        $mock = $this->getMockForTrait(BuildsQueries::class);
+        $mock->tap(function ($builder) use ($mock) {
+            $this->assertEquals($mock, $builder);
+        });
+    }
+}