Experiment with PHP 7.1 compatibility (#4421)

* Experiment with PHP 7.1 compatibility

* Let’s hop

.circleci/config.yml

@@ -4,9 +4,6 @@ executors:
   php-73:
     docker:
       - image: thecodingmachine/php:7.3-v2-cli
-  php-74:
-    docker:
-      - image: thecodingmachine/php:7.4-v3-cli
 jobs:
   install-and-self-analyse:
     executor: php-73
@@ -88,7 +85,7 @@ jobs:
           paths:
             - build/psalm.phar
   test-with-real-projects:
-    executor: php-74
+    executor: php-73
     steps:
       - checkout # used here just for the side effect of loading the github public ssh key so we can clone other stuff
       - attach_workspace:

assets/psalm-phar/composer.json

@@ -3,7 +3,7 @@
 	"description": "Composer-based Psalm Phar",
 	"license": ["MIT"],
 	"require": {
-		"php": "^7.3 || ^8.0"
+		"php": "^7.1 || ^8.0"
 	},
 	"conflict": {
 		"vimeo/psalm" : "*"

composer.json

@@ -14,7 +14,7 @@
         }
     ],
     "require": {
-        "php": "^7.3|^8",
+        "php": "^7.1|^8",
         "ext-SimpleXML": "*",
         "ext-dom": "*",
         "ext-json": "*",
@@ -40,6 +40,7 @@
         "psalm/psalm": "self.version"
     },
     "require-dev": {
+        "php": "^7.3|^8",
         "ext-curl": "*",
         "amphp/amp": "^2.4.2",
         "bamarni/composer-bin-plugin": "^1.2",

docs/running_psalm/installation.md

@@ -1,6 +1,6 @@
 # Installation
 
-The latest version of Psalm requires PHP >= 7.3 and [Composer](https://getcomposer.org/).
+The latest version of Psalm requires PHP >= 7.1 and [Composer](https://getcomposer.org/).
 
 ```bash
 composer require --dev vimeo/psalm