diff --git a/src/Psalm/Internal/Analyzer/MethodComparator.php b/src/Psalm/Internal/Analyzer/MethodComparator.php
index a064be7a1..787af9a8d 100644
--- a/src/Psalm/Internal/Analyzer/MethodComparator.php
+++ b/src/Psalm/Internal/Analyzer/MethodComparator.php
@@ -73,6 +73,7 @@ class MethodComparator
             $cased_implementer_method_id,
             $prevent_method_signature_mismatch,
             $prevent_abstract_override,
+            $codebase->php_major_version >= 8,
             $code_location,
             $suppressed_issues
         );
@@ -203,11 +204,13 @@ class MethodComparator
         string $cased_implementer_method_id,
         bool $prevent_method_signature_mismatch,
         bool $prevent_abstract_override,
+        bool $trait_mismatches_are_fatal,
         CodeLocation $code_location,
         array $suppressed_issues
     ) : void {
         if ($implementer_visibility > $guide_visibility) {
-            if ($guide_classlike_storage->is_trait === $implementer_classlike_storage->is_trait
+            if ($trait_mismatches_are_fatal
+                || $guide_classlike_storage->is_trait === $implementer_classlike_storage->is_trait
                 || !in_array($guide_classlike_storage->name, $implementer_classlike_storage->used_traits)
                 || $implementer_method_storage->defining_fqcln !== $implementer_classlike_storage->name
                 || (!$implementer_method_storage->abstract
@@ -557,7 +560,8 @@ class MethodComparator
         if (!$is_contained_by) {
             $config = \Psalm\Config::getInstance();
 
-            if ($guide_classlike_storage->is_trait === $implementer_classlike_storage->is_trait
+            if ($codebase->php_major_version >= 8
+                || $guide_classlike_storage->is_trait === $implementer_classlike_storage->is_trait
                 || !in_array($guide_classlike_storage->name, $implementer_classlike_storage->used_traits)
                 || $implementer_method_storage->defining_fqcln !== $implementer_classlike_storage->name
                 || (!$implementer_method_storage->abstract
@@ -851,7 +855,8 @@ class MethodComparator
             : UnionTypeComparator::isContainedByInPhp($implementer_signature_return_type, $guide_signature_return_type);
 
         if (!$is_contained_by) {
-            if ($guide_classlike_storage->is_trait === $implementer_classlike_storage->is_trait
+            if ($codebase->php_major_version >= 8
+                || $guide_classlike_storage->is_trait === $implementer_classlike_storage->is_trait
                 || !in_array($guide_classlike_storage->name, $implementer_classlike_storage->used_traits)
                 || $implementer_method_storage->defining_fqcln !== $implementer_classlike_storage->name
                 || (!$implementer_method_storage->abstract
diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/CastAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Expression/CastAnalyzer.php
index 8467a0684..149cd9ec3 100644
--- a/src/Psalm/Internal/Analyzer/Statements/Expression/CastAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/Statements/Expression/CastAnalyzer.php
@@ -171,7 +171,9 @@ class CastAnalyzer
             return true;
         }
 
-        if ($stmt instanceof PhpParser\Node\Expr\Cast\Unset_) {
+        if ($stmt instanceof PhpParser\Node\Expr\Cast\Unset_
+            && $statements_analyzer->getCodebase()->php_major_version < 8
+        ) {
             if (ExpressionAnalyzer::analyze($statements_analyzer, $stmt->expr, $context) === false) {
                 return false;
             }
diff --git a/src/Psalm/Internal/PhpVisitor/ReflectorVisitor.php b/src/Psalm/Internal/PhpVisitor/ReflectorVisitor.php
index 07c15bcf8..8a033c2f9 100644
--- a/src/Psalm/Internal/PhpVisitor/ReflectorVisitor.php
+++ b/src/Psalm/Internal/PhpVisitor/ReflectorVisitor.php
@@ -2004,9 +2004,10 @@ class ReflectorVisitor extends PhpParser\NodeVisitorAbstract implements PhpParse
             $class_name_parts = explode('\\', $fq_classlike_name);
             $class_name = array_pop($class_name_parts);
 
-            if ($method_name_lc === strtolower($class_name) &&
-                !isset($class_storage->methods['__construct']) &&
-                strpos($fq_classlike_name, '\\') === false
+            if ($method_name_lc === strtolower($class_name)
+                && !isset($class_storage->methods['__construct'])
+                && strpos($fq_classlike_name, '\\') === false
+                && $this->codebase->php_major_version < 8
             ) {
                 $this->codebase->methods->setDeclaringMethodId(
                     $fq_classlike_name,