From 0d62fbdf98063f83a13f977bbbe1cf928b9f2166 Mon Sep 17 00:00:00 2001
From: Matthew Brown <github@muglug.com>
Date: Wed, 11 Mar 2020 10:18:40 -0400
Subject: [PATCH] Detect erroneous abstract static method calls

---
 config.xsd                                        |  1 +
 docs/running_psalm/issues.md                      | 12 ++++++++++++
 .../Expression/Call/StaticCallAnalyzer.php        | 15 +++++++++++++++
 src/Psalm/Issue/AbstractMethodCall.php            |  7 +++++++
 tests/MethodCallTest.php                          | 13 +++++++++++++
 5 files changed, 48 insertions(+)
 create mode 100644 src/Psalm/Issue/AbstractMethodCall.php

diff --git a/config.xsd b/config.xsd
index 3083e5931..7e410942a 100644
--- a/config.xsd
+++ b/config.xsd
@@ -157,6 +157,7 @@
         <xs:choice minOccurs="0" maxOccurs="unbounded">
             <xs:element name="PluginIssue" type="PluginIssueHandlerType" minOccurs="0" />
             <xs:element name="AbstractInstantiation" type="IssueHandlerType" minOccurs="0" />
+            <xs:element name="AbstractMethodCall" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="ArgumentTypeCoercion" type="ArgumentIssueHandlerType" minOccurs="0" />
             <xs:element name="AssignmentToVoid" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="CircularReference" type="IssueHandlerType" minOccurs="0" />
diff --git a/docs/running_psalm/issues.md b/docs/running_psalm/issues.md
index 2e39f7173..e5d97040c 100644
--- a/docs/running_psalm/issues.md
+++ b/docs/running_psalm/issues.md
@@ -9,6 +9,18 @@ abstract class A {}
 new A();
 ```
 
+### AbstractMethodCall
+
+Emitted when an attempt is made to call an abstract method
+
+```php
+abstract class Base {
+    abstract static function bar() : void;
+}
+
+Base::bar();
+```
+
 ### ArgumentTypeCoercion
 
 Emitted when calling a function with an argument which has a less specific type than the function expects
diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/Call/StaticCallAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Expression/Call/StaticCallAnalyzer.php
index 61cb8ed40..8e517fc55 100644
--- a/src/Psalm/Internal/Analyzer/Statements/Expression/Call/StaticCallAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/Statements/Expression/Call/StaticCallAnalyzer.php
@@ -10,6 +10,7 @@ use Psalm\Internal\Analyzer\StatementsAnalyzer;
 use Psalm\CodeLocation;
 use Psalm\Context;
 use Psalm\Internal\FileManipulation\FileManipulationBuffer;
+use Psalm\Issue\AbstractMethodCall;
 use Psalm\Issue\DeprecatedClass;
 use Psalm\Issue\ImpureMethodCall;
 use Psalm\Issue\InvalidStringClass;
@@ -952,6 +953,20 @@ class StaticCallAnalyzer extends \Psalm\Internal\Analyzer\Statements\Expression\
                 $method_storage = $codebase->methods->getUserMethodStorage($method_id);
 
                 if ($method_storage) {
+                    if ($method_storage->abstract) {
+                        if (IssueBuffer::accepts(
+                            new AbstractMethodCall(
+                                'Cannot call an abstract method ' . $method_id,
+                                new CodeLocation($statements_analyzer->getSource(), $stmt)
+                            ),
+                            $statements_analyzer->getSuppressedIssues()
+                        )) {
+                            // fall through
+                        }
+
+                        return;
+                    }
+
                     if ($context->pure && !$method_storage->pure) {
                         if (IssueBuffer::accepts(
                             new ImpureMethodCall(
diff --git a/src/Psalm/Issue/AbstractMethodCall.php b/src/Psalm/Issue/AbstractMethodCall.php
new file mode 100644
index 000000000..8326d59ef
--- /dev/null
+++ b/src/Psalm/Issue/AbstractMethodCall.php
@@ -0,0 +1,7 @@
+<?php
+namespace Psalm\Issue;
+
+class AbstractMethodCall extends CodeIssue
+{
+    const ERROR_LEVEL = -1;
+}
diff --git a/tests/MethodCallTest.php b/tests/MethodCallTest.php
index 0c6953466..0f7f5a992 100644
--- a/tests/MethodCallTest.php
+++ b/tests/MethodCallTest.php
@@ -871,6 +871,19 @@ class MethodCallTest extends TestCase
                     }',
                 'error_message' => 'InvalidStringClass',
             ],
+            'preventAbstractMethodCall' => [
+                '<?php
+                    abstract class Base {
+                        public static function callAbstract() : void {
+                            static::bar();
+                        }
+
+                        abstract static function bar() : void;
+                    }
+
+                    Base::bar();',
+                'error_message' => 'AbstractMethodCall',
+            ],
         ];
     }
 }