From 911ac2d363f8f99a343ba20387c8547978d96218 Mon Sep 17 00:00:00 2001
From: SignpostMarv <me@signpostmarv.name>
Date: Mon, 18 May 2020 18:42:47 +0100
Subject: [PATCH] Infer numeric-string from (string)$numeric (#3390)

* adding test for vimeo/psalm#3370

* check if typecast will result in numeric-string

* int & float as per examples in vimeo/psalm#3370
* numeric & numeric-string because they shouldn't lose numericness.

* satisfy phpcs

* adjusting assertions to reflect typecasting change
---
 .../Analyzer/Statements/ExpressionAnalyzer.php |  9 +++++++++
 tests/ReturnTypeTest.php                       |  8 ++++----
 tests/TypeReconciliation/ValueTest.php         | 18 ++++++++++++++++++
 3 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/src/Psalm/Internal/Analyzer/Statements/ExpressionAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/ExpressionAnalyzer.php
index 900c17c38..4907d540f 100644
--- a/src/Psalm/Internal/Analyzer/Statements/ExpressionAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/Statements/ExpressionAnalyzer.php
@@ -1707,6 +1707,15 @@ class ExpressionAnalyzer
         while ($atomic_types) {
             $atomic_type = \array_pop($atomic_types);
 
+            if ($atomic_type instanceof TFloat
+                || $atomic_type instanceof TInt
+                || $atomic_type instanceof Type\Atomic\TNumeric
+                || $atomic_type instanceof Type\Atomic\TNumericString
+            ) {
+                $castable_types[] = new Type\Atomic\TNumericString();
+                continue;
+            }
+
             if ($atomic_type instanceof TString) {
                 $valid_strings[] = $atomic_type;
                 continue;
diff --git a/tests/ReturnTypeTest.php b/tests/ReturnTypeTest.php
index 5281d32bf..f90d3bc2e 100644
--- a/tests/ReturnTypeTest.php
+++ b/tests/ReturnTypeTest.php
@@ -718,7 +718,7 @@ class ReturnTypeTest extends TestCase
                     $res = map(function(int $i): string { return (string) $i; })([1,2,3]);
                 ',
                 'assertions' => [
-                    '$res' => 'iterable<mixed, string>',
+                    '$res' => 'iterable<mixed, numeric-string>',
                 ],
             ],
             'infersArrowClosureReturnTypes' => [
@@ -756,7 +756,7 @@ class ReturnTypeTest extends TestCase
                     $res = map(function(int $i): string { return (string) $i; })([1,2,3]);
                 ',
                 'assertions' => [
-                    '$res' => 'iterable<mixed, string>',
+                    '$res' => 'iterable<mixed, numeric-string>',
                 ],
             ],
             'infersCallableReturnTypes' => [
@@ -778,7 +778,7 @@ class ReturnTypeTest extends TestCase
                     $res = map(function(int $i): string { return (string) $i; })([1,2,3]);
                 ',
                 'assertions' => [
-                    '$res' => 'iterable<mixed, string>',
+                    '$res' => 'iterable<mixed, numeric-string>',
                 ],
             ],
             'infersCallableReturnTypesWithPartialTypehinting' => [
@@ -800,7 +800,7 @@ class ReturnTypeTest extends TestCase
                     $res = map(function(int $i): string { return (string) $i; })([1,2,3]);
                 ',
                 'assertions' => [
-                    '$res' => 'iterable<mixed, string>',
+                    '$res' => 'iterable<mixed, numeric-string>',
                 ],
             ],
             'mixedAssignmentWithUnderscore' => [
diff --git a/tests/TypeReconciliation/ValueTest.php b/tests/TypeReconciliation/ValueTest.php
index 80daeb0de..3be8551cd 100644
--- a/tests/TypeReconciliation/ValueTest.php
+++ b/tests/TypeReconciliation/ValueTest.php
@@ -693,6 +693,24 @@ class ValueTest extends TestCase
                         return 5;
                     }',
             ],
+            'numericStringCastFromInt' => [
+                '<?php
+                    /**
+                     * @return numeric-string
+                     */
+                    function makeNumStringFromInt(int $v) {
+                        return (string) $v;
+                    }',
+            ],
+            'numericStringCastFromFloat' => [
+                '<?php
+                    /**
+                     * @return numeric-string
+                     */
+                    function makeNumStringFromFloat(float $v) {
+                        return (string) $v;
+                    }'
+                ],
         ];
     }