fix: phpstan issues

Author: tpetry

src/Schema/Grammars/GrammarIndex.php

@@ -167,19 +167,19 @@ private function genericCompileCreateIndex(Blueprint $blueprint, Fluent $command
 
         $index = [
             $unique ? 'create unique index' : 'create index',
-            $command['concurrently'] ? 'concurrently' : '',
-            $command['ifNotExists'] ? 'if not exists' : '',
+            $command['concurrently'] ? 'concurrently' : null,
+            $command['ifNotExists'] ? 'if not exists' : null,
             $this->wrap($command['index']),
             'on',
             $this->wrapTable($blueprint),
-            $command['algorithm'] ? "using {$command['algorithm']}" : '',
+            $command['algorithm'] ? "using {$command['algorithm']}" : null,
             '('.implode(', ', $columns).')',
-            $command['include'] ? 'include ('.implode(',', $this->wrapArray(Arr::wrap($command['include']))).')' : '',
-            $command['nullsNotDistinct'] ? 'nulls not distinct' : '',
-            $command['with'] ? "with ({$command['with']})" : '',
-            $command['where'] ? "where {$command['where']}" : '',
+            $command['include'] ? 'include ('.implode(',', $this->wrapArray(Arr::wrap($command['include']))).')' : null,
+            $command['nullsNotDistinct'] ? 'nulls not distinct' : null,
+            $command['with'] ? "with ({$command['with']})" : null,
+            $command['where'] ? "where {$command['where']}" : null,
         ];
-        $sql = implode(' ', array_filter($index, fn ($part) => $part));
+        $sql = implode(' ', array_filter($index, fn (?string $part) => filled($part)));
 
         return $sql;
     }

src/Schema/Grammars/GrammarTrigger.php

@@ -37,7 +37,7 @@ public function compileTrigger(Blueprint $blueprint, Fluent $command): string
             $new = transform($command['transitionTables']['new'], fn (string $table) => "new table as {$this->wrap($table)}");
             $old = transform($command['transitionTables']['old'], fn (string $table) => "old table as {$this->wrap($table)}");
             if (filled($new) || filled($old)) {
-                $referencing = implode(' ', array_filter(['referencing', $new, $old], fn ($part) => $part));
+                $referencing = implode(' ', array_filter(['referencing', $new, $old], fn (?string $part) => filled($part)));
             }
         }
 
@@ -68,7 +68,7 @@ public function compileTrigger(Blueprint $blueprint, Fluent $command): string
             $when ?? null,
             "execute function {$command['action']}",
         ];
-        $sql = implode(' ', array_filter($index, fn ($part) => $part));
+        $sql = implode(' ', array_filter($index, fn (?string $part) => filled($part)));
 
         return $sql;
     }