diff --git a/src/Psalm/ErrorBaseline.php b/src/Psalm/ErrorBaseline.php
index 2deee69eb..b9a42aba0 100644
--- a/src/Psalm/ErrorBaseline.php
+++ b/src/Psalm/ErrorBaseline.php
@@ -20,6 +20,8 @@ use RuntimeException;
 use function str_replace;
 use function strpos;
 use function usort;
+use function count;
+use function array_values;
 
 class ErrorBaseline
 {
@@ -198,16 +200,11 @@ class ErrorBaseline
      */
     private static function countIssueTypesByFile(array $issues): array
     {
-        $normalized_data = [];
-
-        foreach ($issues as $file_issues) {
-            foreach ($file_issues as $issue_data) {
-                $normalized_data[] = $issue_data;
-            }
+        if (0 === count($issues)) {
+            return [];
         }
-
         $groupedIssues = array_reduce(
-            $normalized_data,
+            array_merge(...array_values($issues)),
             /**
              * @param array<string,array<string,array{o:int, s:array<int, string>}>> $carry
              * @param array{type: string, file_name: string, severity: string, selected_text: string} $issue
diff --git a/src/Psalm/IssueBuffer.php b/src/Psalm/IssueBuffer.php
index dd1cecba4..bf56c8ee8 100644
--- a/src/Psalm/IssueBuffer.php
+++ b/src/Psalm/IssueBuffer.php
@@ -29,6 +29,8 @@ use function sha1;
 use function str_repeat;
 use function str_replace;
 use function usort;
+use function array_merge;
+use function array_values;
 
 class IssueBuffer
 {
@@ -619,13 +621,7 @@ class IssueBuffer
         $total_expression_count = $mixed_counts[0] + $mixed_counts[1];
         $mixed_expression_count = $mixed_counts[0];
 
-        $normalized_data = [];
-
-        foreach (self::$issues_data as $file_issues) {
-            foreach ($file_issues as $issue_data) {
-                $normalized_data[] = $issue_data;
-            }
-        }
+        $normalized_data = 0 === count(self::$issues_data) ? [] : array_merge(...array_values(self::$issues_data));
 
         switch ($report_options->format) {
             case Report::TYPE_COMPACT:
diff --git a/src/Psalm/Plugin/Shepherd.php b/src/Psalm/Plugin/Shepherd.php
index 1b3568d32..91e592a05 100644
--- a/src/Psalm/Plugin/Shepherd.php
+++ b/src/Psalm/Plugin/Shepherd.php
@@ -23,6 +23,9 @@ use Psalm\SourceControl\SourceControlInfo;
 use const STDERR;
 use function strlen;
 use function var_export;
+use function count;
+use function array_merge;
+use function array_values;
 
 class Shepherd implements \Psalm\Plugin\Hook\AfterAnalysisInterface
 {
@@ -56,15 +59,15 @@ class Shepherd implements \Psalm\Plugin\Hook\AfterAnalysisInterface
         unset($build_info['git']);
 
         if ($build_info) {
-            $normalized_data = [];
-
-            foreach ($issues as $file_issues) {
-                foreach ($file_issues as $issue_data) {
-                    if ($issue_data['severity'] === 'error') {
-                        $normalized_data[] = $issue_data;
-                    }
+            $normalized_data = 0 === count($issues) ? [] : array_filter(
+                array_merge(...array_values($issues)),
+                /**
+                 * @param array{severity: string} $i
+                 */
+                static function (array $i) : bool {
+                    return $i['severity'] === 'error';
                 }
-            }
+            );
 
             $data = [
                 'build' => $build_info,