diff --git a/src/Psalm/Internal/Analyzer/FunctionLikeAnalyzer.php b/src/Psalm/Internal/Analyzer/FunctionLikeAnalyzer.php
index 84ae09bc0..281710737 100644
--- a/src/Psalm/Internal/Analyzer/FunctionLikeAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/FunctionLikeAnalyzer.php
@@ -359,19 +359,16 @@ abstract class FunctionLikeAnalyzer extends SourceAnalyzer implements Statements
                 );
             }
 
-            if ($function_param->type) {
-                if ($function_param->type_location) {
-                    if ($function_param->type->check(
-                        $this,
-                        $function_param->type_location,
-                        $storage->suppressed_issues,
-                        [],
-                        false
-                    ) === false) {
-                        $check_stmts = false;
-                    }
-                }
+            if ($signature_type) {
+                $signature_type = ExpressionAnalyzer::fleshOutType(
+                    $codebase,
+                    $signature_type,
+                    $context->self,
+                    $context->self
+                );
+            }
 
+            if ($function_param->type) {
                 $is_signature_type = $function_param->type === $function_param->signature_type;
 
                 if ($is_signature_type
@@ -390,6 +387,18 @@ abstract class FunctionLikeAnalyzer extends SourceAnalyzer implements Statements
                     $context->self,
                     $context->self
                 );
+
+                if ($function_param->type_location) {
+                    if ($param_type->check(
+                        $this,
+                        $function_param->type_location,
+                        $storage->suppressed_issues,
+                        [],
+                        false
+                    ) === false) {
+                        $check_stmts = false;
+                    }
+                }
             } else {
                 if (!$non_null_param_types && isset($implemented_docblock_param_types[$offset])) {
                     $param_type = clone $implemented_docblock_param_types[$offset];
diff --git a/src/Psalm/Internal/Analyzer/MethodAnalyzer.php b/src/Psalm/Internal/Analyzer/MethodAnalyzer.php
index 066ad3f7c..59a8af41c 100644
--- a/src/Psalm/Internal/Analyzer/MethodAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/MethodAnalyzer.php
@@ -727,22 +727,42 @@ class MethodAnalyzer extends FunctionLikeAnalyzer
             if ($prevent_method_signature_mismatch
                 && $guide_classlike_storage->user_defined
                 && $implementer_param->signature_type
-                && !TypeAnalyzer::isContainedByInPhp($guide_param->signature_type, $implementer_param->signature_type)
             ) {
-                if (IssueBuffer::accepts(
-                    new MethodSignatureMismatch(
-                        'Argument ' . ($i + 1) . ' of ' . $cased_implementer_method_id . ' has wrong type \'' .
-                            $implementer_param->signature_type . '\', expecting \'' .
-                            $guide_param->signature_type . '\' as defined by ' .
-                            $cased_guide_method_id,
-                        $implementer_method_storage->params[$i]->location
-                            ?: $code_location
+                $guide_param_signature_type = $guide_param->signature_type
+                    ? ExpressionAnalyzer::fleshOutType(
+                        $codebase,
+                        $guide_param->signature_type,
+                        $guide_classlike_storage->name,
+                        $guide_classlike_storage->name
                     )
-                )) {
-                    return false;
-                }
+                    : null;
 
-                return null;
+                $implementer_param_signature_type = ExpressionAnalyzer::fleshOutType(
+                    $codebase,
+                    $implementer_param->signature_type,
+                    $implementer_classlike_storage->name,
+                    $implementer_classlike_storage->name
+                );
+
+                if (!TypeAnalyzer::isContainedByInPhp(
+                    $guide_param_signature_type,
+                    $implementer_param_signature_type
+                )) {
+                    if (IssueBuffer::accepts(
+                        new MethodSignatureMismatch(
+                            'Argument ' . ($i + 1) . ' of ' . $cased_implementer_method_id . ' has wrong type \'' .
+                                $implementer_param_signature_type . '\', expecting \'' .
+                                $guide_param_signature_type . '\' as defined by ' .
+                                $cased_guide_method_id,
+                            $implementer_method_storage->params[$i]->location
+                                ?: $code_location
+                        )
+                    )) {
+                        return false;
+                    }
+
+                    return null;
+                }
             }
 
             if ($guide_classlike_storage->user_defined
diff --git a/src/Psalm/Internal/Visitor/ReflectorVisitor.php b/src/Psalm/Internal/Visitor/ReflectorVisitor.php
index 1f1e06ab6..93a7a0f1c 100644
--- a/src/Psalm/Internal/Visitor/ReflectorVisitor.php
+++ b/src/Psalm/Internal/Visitor/ReflectorVisitor.php
@@ -2139,10 +2139,15 @@ class ReflectorVisitor extends PhpParser\NodeVisitorAbstract implements PhpParse
             } elseif ($param_typehint instanceof PhpParser\Node\Name\FullyQualified) {
                 $param_type_string = (string)$param_typehint;
                 $this->codebase->scanner->queueClassLikeForScanning($param_type_string, $this->file_path);
-            } elseif (strtolower($param_typehint->parts[0]) === 'self') {
-                $param_type_string = $this->fq_classlike_names[count($this->fq_classlike_names) - 1];
             } else {
-                $param_type_string = ClassLikeAnalyzer::getFQCLNFromNameObject($param_typehint, $this->aliases);
+                if ($this->classlike_storages
+                    && strtolower($param_typehint->parts[0]) === 'self'
+                    && !end($this->classlike_storages)->is_trait
+                ) {
+                    $param_type_string = $this->fq_classlike_names[count($this->fq_classlike_names) - 1];
+                } else {
+                    $param_type_string = ClassLikeAnalyzer::getFQCLNFromNameObject($param_typehint, $this->aliases);
+                }
 
                 if (!in_array(strtolower($param_type_string), ['self', 'static', 'parent'], true)) {
                     $this->codebase->scanner->queueClassLikeForScanning($param_type_string, $this->file_path);
diff --git a/tests/TraitTest.php b/tests/TraitTest.php
index 66202c342..b1bba0726 100644
--- a/tests/TraitTest.php
+++ b/tests/TraitTest.php
@@ -839,6 +839,18 @@ class TraitTest extends TestCase
                         public function bar() { return []; }
                     }'
             ],
+            'traitSelfParam' => [
+                '<?php
+                    trait T {
+                        public function bar(self $object): self {
+                            return $this;
+                        }
+                    }
+
+                    class Foo {
+                        use T;
+                    }',
+            ],
         ];
     }