Fix uniqueness of macroable objects on grammars

src/Illuminate/Database/Grammar.php

@@ -2,13 +2,10 @@
 
 namespace Illuminate\Database;
 
-use Illuminate\Support\Traits\Macroable;
 use Illuminate\Database\Query\Expression;
 
 abstract class Grammar
 {
-    use Macroable;
-
     /**
      * The grammar table prefix.
      *

src/Illuminate/Database/Query/Grammars/MySqlGrammar.php

@@ -5,10 +5,13 @@
 use Illuminate\Support\Arr;
 use Illuminate\Support\Str;
 use Illuminate\Database\Query\Builder;
+use Illuminate\Support\Traits\Macroable;
 use Illuminate\Database\Query\JsonExpression;
 
 class MySqlGrammar extends Grammar
 {
+    use Macroable;
+
     /**
      * The grammar specific operators.
      *

src/Illuminate/Database/Query/Grammars/PostgresGrammar.php

@@ -5,9 +5,12 @@
 use Illuminate\Support\Arr;
 use Illuminate\Support\Str;
 use Illuminate\Database\Query\Builder;
+use Illuminate\Support\Traits\Macroable;
 
 class PostgresGrammar extends Grammar
 {
+    use Macroable;
+
     /**
      * All of the available clause operators.
      *

src/Illuminate/Database/Query/Grammars/SQLiteGrammar.php

@@ -5,9 +5,12 @@
 use Illuminate\Support\Arr;
 use Illuminate\Support\Str;
 use Illuminate\Database\Query\Builder;
+use Illuminate\Support\Traits\Macroable;
 
 class SQLiteGrammar extends Grammar
 {
+    use Macroable;
+
     /**
      * The components that make up a select clause.
      *

src/Illuminate/Database/Query/Grammars/SqlServerGrammar.php

@@ -4,9 +4,12 @@
 
 use Illuminate\Support\Arr;
 use Illuminate\Database\Query\Builder;
+use Illuminate\Support\Traits\Macroable;
 
 class SqlServerGrammar extends Grammar
 {
+    use Macroable;
+
     /**
      * All of the available clause operators.
      *

src/Illuminate/Database/Schema/Grammars/MySqlGrammar.php

@@ -4,10 +4,13 @@
 
 use Illuminate\Support\Fluent;
 use Illuminate\Database\Connection;
+use Illuminate\Support\Traits\Macroable;
 use Illuminate\Database\Schema\Blueprint;
 
 class MySqlGrammar extends Grammar
 {
+    use Macroable;
+
     /**
      * The possible column modifiers.
      *

src/Illuminate/Database/Schema/Grammars/PostgresGrammar.php

@@ -3,10 +3,13 @@
 namespace Illuminate\Database\Schema\Grammars;
 
 use Illuminate\Support\Fluent;
+use Illuminate\Support\Traits\Macroable;
 use Illuminate\Database\Schema\Blueprint;
 
 class PostgresGrammar extends Grammar
 {
+    use Macroable;
+
     /**
      * If this Grammar supports schema changes wrapped in a transaction.
      *

src/Illuminate/Database/Schema/Grammars/SQLiteGrammar.php

@@ -7,10 +7,13 @@
 use Illuminate\Support\Fluent;
 use Doctrine\DBAL\Schema\Index;
 use Illuminate\Database\Connection;
+use Illuminate\Support\Traits\Macroable;
 use Illuminate\Database\Schema\Blueprint;
 
 class SQLiteGrammar extends Grammar
 {
+    use Macroable;
+
     /**
      * The possible column modifiers.
      *

src/Illuminate/Database/Schema/Grammars/SqlServerGrammar.php

@@ -3,10 +3,13 @@
 namespace Illuminate\Database\Schema\Grammars;
 
 use Illuminate\Support\Fluent;
+use Illuminate\Support\Traits\Macroable;
 use Illuminate\Database\Schema\Blueprint;
 
 class SqlServerGrammar extends Grammar
 {
+    use Macroable;
+
     /**
      * If this Grammar supports schema changes wrapped in a transaction.
      *

tests/Database/DatabaseGrammarTest.php

@@ -0,0 +1,66 @@
+<?php
+
+namespace Illuminate\Tests\Database;
+
+use PHPUnit\Framework\TestCase;
+use Illuminate\Database\Schema\Grammars\SqlServerGrammar as SqlServerSchemaGrammar;
+use Illuminate\Database\Schema\Grammars\PostgresGrammar as PostgresSchemaGrammar;
+use Illuminate\Database\Schema\Grammars\MySqlGrammar as MySqlSchemaGrammar;
+use Illuminate\Database\Schema\Grammars\SQLiteGrammar as SQLiteSchemaGrammar;
+use Illuminate\Database\Query\Grammars\MySqlGrammar as MySqlQueryGrammar;
+use Illuminate\Database\Query\Grammars\SQLiteGrammar as SQLiteQueryGrammar;
+use Illuminate\Database\Query\Grammars\SqlServerGrammar as SqlServerQueryGrammar;
+use Illuminate\Database\Query\Grammars\PostgresGrammar as PostgresQueryGrammar;
+
+class DatabaseGrammarTest extends TestCase
+{
+    public function testMacroableFunctionsAreUniquePerGrammarQueryClass()
+    {
+        // compileReplace macro.
+        MySqlQueryGrammar::macro('compileReplace', function () {
+            return MySqlQueryGrammar::class;
+        });
+
+        SQLiteQueryGrammar::macro('compileReplace', function () {
+            return SQLiteQueryGrammar::class;
+        });
+
+        PostgresQueryGrammar::macro('compileReplace', function () {
+            return PostgresQueryGrammar::class;
+        });
+
+        SqlServerQueryGrammar::macro('compileReplace', function () {
+            return SqlServerQueryGrammar::class;
+        });
+
+        $this->assertSame(MySqlQueryGrammar::class, (new MySqlQueryGrammar())->compileReplace());
+        $this->assertSame(SqlServerQueryGrammar::class, (new SqlServerQueryGrammar())->compileReplace());
+        $this->assertSame(PostgresQueryGrammar::class, (new PostgresQueryGrammar())->compileReplace());
+        $this->assertSame(SQLiteQueryGrammar::class, (new SQLiteQueryGrammar())->compileReplace());
+    }
+
+    public function testMacroableFunctionsAreUniquePerGrammarSchemaClass()
+    {
+        // compileReplace macro.
+        MySqlSchemaGrammar::macro('compileReplace', function () {
+            return MySqlSchemaGrammar::class;
+        });
+
+        SQLiteSchemaGrammar::macro('compileReplace', function () {
+            return SQLiteSchemaGrammar::class;
+        });
+
+        PostgresSchemaGrammar::macro('compileReplace', function () {
+            return PostgresSchemaGrammar::class;
+        });
+
+        SqlServerSchemaGrammar::macro('compileReplace', function () {
+            return SqlServerSchemaGrammar::class;
+        });
+
+        $this->assertSame(MySqlSchemaGrammar::class, (new MySqlSchemaGrammar())->compileReplace());
+        $this->assertSame(SqlServerSchemaGrammar::class, (new SqlServerSchemaGrammar())->compileReplace());
+        $this->assertSame(PostgresSchemaGrammar::class, (new PostgresSchemaGrammar())->compileReplace());
+        $this->assertSame(SQLiteSchemaGrammar::class, (new SQLiteSchemaGrammar())->compileReplace());
+    }
+}