better inference of string increment (#5777)

* better inference of string increment * fix combination
vimeo · May 17, 2021 · 4c4d574 · 4c4d574
1 parent f6bdeb6
commit 4c4d574
Show file tree

Hide file tree

Showing 3 changed files with 18 additions and 7 deletions.
diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/BinaryOp/NonDivArithmeticOpAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Expression/BinaryOp/NonDivArithmeticOpAnalyzer.php
@@ -384,9 +384,9 @@ private static function analyzeNonDivOperands(
             $has_string_increment = true;
 
             if (!$result_type) {
-                $result_type = Type::getString();
+                $result_type = Type::getNonEmptyString();
             } else {
-                $result_type = Type::combineUnionTypes(Type::getString(), $result_type);
+                $result_type = Type::combineUnionTypes(Type::getNonEmptyString(), $result_type);
             }
 
             $has_valid_left_operand = true;

diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/IncDecExpressionAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Expression/IncDecExpressionAnalyzer.php
@@ -42,7 +42,7 @@ public static function analyze(
         $stmt_var_type = $statements_analyzer->node_data->getType($stmt->var);
 
         if ($stmt instanceof PostInc || $stmt instanceof PostDec) {
-            $statements_analyzer->node_data->setType($stmt, $stmt_var_type ?: Type::getMixed());
+            $statements_analyzer->node_data->setType($stmt, $stmt_var_type ?? Type::getMixed());
         }
 
         if (($stmt_var_type = $statements_analyzer->node_data->getType($stmt->var))
@@ -64,9 +64,8 @@ public static function analyze(
                 $context
             );
 
-            $stmt_type = clone $stmt_var_type;
-
-            $statements_analyzer->node_data->setType($stmt, $stmt_type);
+            $result_type = $return_type ?? Type::getMixed();
+            $statements_analyzer->node_data->setType($stmt, $result_type);
 
             BinaryOpAnalyzer::addDataFlow(
                 $statements_analyzer,
@@ -81,7 +80,7 @@ public static function analyze(
             $codebase = $statements_analyzer->getCodebase();
 
             if ($var_id && isset($context->vars_in_scope[$var_id])) {
-                $context->vars_in_scope[$var_id] = $stmt_type;
+                $context->vars_in_scope[$var_id] = $result_type;
 
                 if ($codebase->find_unused_variables && $stmt->var instanceof PhpParser\Node\Expr\Variable) {
                     $context->assigned_var_ids[$var_id] = (int) $stmt->var->getAttribute('startFilePos');

diff --git a/tests/BinaryOperationTest.php b/tests/BinaryOperationTest.php
@@ -384,6 +384,18 @@ function scope(){
                     '$a' => 'string',
                 ],
             ],
+            'stringIncrementWithCheck' => [
+                '<?php
+                    /** @psalm-suppress StringIncrement */
+                    for($a = "a"; $a != "z"; $a++){
+                        if($a === "b"){
+                            echo "b reached";
+                        }
+                    }',
+                'assertions' => [
+                    '$a===' => 'non-empty-string',
+                ],
+            ],
             'nullCoalescingAssignment' => [
                 '<?php
                     function foo(?string $s): string {