From ee4a3882a7272fd6f2987f362b43a80cc063d0c8 Mon Sep 17 00:00:00 2001
From: Matthew Brown <github@muglug.com>
Date: Fri, 30 Dec 2016 23:40:32 -0500
Subject: [PATCH] Check method defaults to see whether they match

---
 config.xsd                                |  1 +
 src/Psalm/Checker/FunctionChecker.php     |  2 +-
 src/Psalm/Checker/FunctionLikeChecker.php | 21 ++++++++++++++++++++-
 src/Psalm/Issue/InvalidParamDefault.php   |  6 ++++++
 tests/MethodSignatureTest.php             | 19 +++++++++++++++++++
 5 files changed, 47 insertions(+), 2 deletions(-)
 create mode 100644 src/Psalm/Issue/InvalidParamDefault.php

diff --git a/config.xsd b/config.xsd
index c8b1344c7..c8e0e661c 100644
--- a/config.xsd
+++ b/config.xsd
@@ -84,6 +84,7 @@
             <xs:element name="InvalidArrayAccess" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="InvalidArrayAssignment" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="InvalidClass" type="IssueHandlerType" minOccurs="0" />
+            <xs:element name="InvalidParamDefault" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="InvalidDocblock" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="InvalidGlobal" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="InvalidIterator" type="IssueHandlerType" minOccurs="0" />
diff --git a/src/Psalm/Checker/FunctionChecker.php b/src/Psalm/Checker/FunctionChecker.php
index ad24dae35..78d5913bd 100644
--- a/src/Psalm/Checker/FunctionChecker.php
+++ b/src/Psalm/Checker/FunctionChecker.php
@@ -76,7 +76,7 @@ class FunctionChecker extends FunctionLikeChecker
     /**
      * @param  string $function_id
      * @param  string $file_path
-     * @return array<FunctionLikeParameter>
+     * @return array<int, FunctionLikeParameter>
      */
     public static function getParams($function_id, $file_path)
     {
diff --git a/src/Psalm/Checker/FunctionLikeChecker.php b/src/Psalm/Checker/FunctionLikeChecker.php
index 482bd819e..ff35bd28a 100644
--- a/src/Psalm/Checker/FunctionLikeChecker.php
+++ b/src/Psalm/Checker/FunctionLikeChecker.php
@@ -13,6 +13,7 @@ use Psalm\EffectsAnalyser;
 use Psalm\Exception\DocblockParseException;
 use Psalm\FunctionLikeParameter;
 use Psalm\Issue\InvalidDocblock;
+use Psalm\Issue\InvalidParamDefault;
 use Psalm\Issue\InvalidReturnType;
 use Psalm\Issue\InvalidToString;
 use Psalm\Issue\MethodSignatureMismatch;
@@ -340,7 +341,7 @@ abstract class FunctionLikeChecker extends SourceChecker implements StatementsSo
             ]);
         }
 
-        foreach ($function_params as $function_param) {
+        foreach ($function_params as $offset => $function_param) {
             $param_type = ExpressionChecker::fleshOutTypes(
                 clone $function_param->type,
                 [],
@@ -352,6 +353,24 @@ abstract class FunctionLikeChecker extends SourceChecker implements StatementsSo
                 throw new \UnexpectedValueException('We should know where this code is');
             }
 
+            $parser_param = $this->function->getParams()[$offset];
+
+            if ($parser_param->default) {
+                $default_type = StatementsChecker::getSimpleType($parser_param->default);
+
+                if ($default_type && !TypeChecker::isContainedBy($default_type, $param_type)) {
+                    if (IssueBuffer::accepts(
+                        new InvalidParamDefault(
+                            'Default value for argument ' . ($offset + 1) . ' of method ' . $this->getMethodId() .
+                                ' does not match the given type ' . $param_type,
+                            $function_param->code_location
+                        )
+                    )) {
+                        return false;
+                    }
+                }
+            }
+
             foreach ($param_type->types as $atomic_type) {
                 if ($atomic_type->isObjectType()
                     && !$atomic_type->isObject()
diff --git a/src/Psalm/Issue/InvalidParamDefault.php b/src/Psalm/Issue/InvalidParamDefault.php
new file mode 100644
index 000000000..bb70a8b27
--- /dev/null
+++ b/src/Psalm/Issue/InvalidParamDefault.php
@@ -0,0 +1,6 @@
+<?php
+namespace Psalm\Issue;
+
+class InvalidParamDefault extends CodeError
+{
+}
diff --git a/tests/MethodSignatureTest.php b/tests/MethodSignatureTest.php
index 667667793..7c7906dd7 100644
--- a/tests/MethodSignatureTest.php
+++ b/tests/MethodSignatureTest.php
@@ -94,4 +94,23 @@ class MethodSignatureTest extends PHPUnit_Framework_TestCase
         $context = new Context('somefile.php');
         $file_checker->check(true, true, $context);
     }
+
+    /**
+     * @expectedException \Psalm\Exception\CodeException
+     * @expectedExceptionMessage InvalidParamDefault
+     */
+    public function testInvalidDefault()
+    {
+        $stmts = self::$parser->parse('<?php
+        class A {
+            public function fooFoo(int $a = "hello") : void {
+
+            }
+        }
+        ');
+
+        $file_checker = new FileChecker('somefile.php', $stmts);
+        $context = new Context('somefile.php');
+        $file_checker->check(true, true, $context);
+    }
 }