Fix overeager inference

src/Psalm/Internal/Algebra.php

@@ -248,6 +248,10 @@ class Algebra
             }
 
             foreach ($clause->possibilities as $var => $possible_types) {
+                if ($var[0] === '*') {
+                    continue;
+                }
+
                 // if there's only one possible type, return it
                 if (count($clause->possibilities) === 1 && count($possible_types) === 1) {
                     $possible_type = array_pop($possible_types);
@@ -551,6 +555,13 @@ class Algebra
      */
     public static function negateFormula(array $clauses): array
     {
+        $clauses = array_filter(
+            $clauses,
+            function ($clause) {
+                return $clause->reconcilable;
+            }
+        );
+
         if (!$clauses) {
             $cond_id = \mt_rand(0, 100000000);
             return [new Clause([], $cond_id, $cond_id, true)];

src/Psalm/Internal/Algebra/FormulaGenerator.php

@@ -350,6 +350,10 @@ class FormulaGenerator
             return $clauses;
         }
 
-        return [new Clause([], $conditional_object_id, $creating_object_id, true)];
+        /** @psalm-suppress MixedOperand */
+        $conditional_ref = '*' . $conditional->getAttribute('startFilePos')
+            . ':' . $conditional->getAttribute('endFilePos');
+
+        return [new Clause([$conditional_ref => ['!falsy']], $conditional_object_id, $creating_object_id)];
     }
 }

src/Psalm/Internal/Analyzer/AlgebraAnalyzer.php

@@ -27,7 +27,7 @@ class AlgebraAnalyzer
      *
      * @param  list<Clause>   $formula_1
      * @param  list<Clause>   $formula_2
-     * @param  array<string, mixed>  $new_assigned_var_ids
+     * @param  array<string, int>  $new_assigned_var_ids
      */
     public static function checkForParadox(
         array $formula_1,

src/Psalm/Internal/Analyzer/Statements/Block/IfAnalyzer.php

@@ -307,6 +307,8 @@ class IfAnalyzer
             $if_scope->if_cond_changed_var_ids = $changed_var_ids;
         }
 
+        $if_context->reconciled_expression_clauses = [];
+
         $old_if_context = clone $if_context;
         $context->vars_possibly_in_scope = array_merge(
             $if_context->vars_possibly_in_scope,

src/Psalm/Internal/Analyzer/Statements/Expression/Call/Method/MethodCallPurityAnalyzer.php

@@ -120,10 +120,7 @@ class MethodCallPurityAnalyzer
             && !$method_storage->mutation_free
             && !$method_pure_compatible
         ) {
-            if (!$method_storage->mutation_free) {
             $statements_analyzer->getSource()->inferred_has_mutation = true;
-            }
-
             $statements_analyzer->getSource()->inferred_impure = true;
         }
 

tests/AlgebraTest.php

@@ -55,6 +55,19 @@ class AlgebraTest extends TestCase
         $this->assertSame(['$b' => ['falsy']], $negated_formula[2]->possibilities);
     }
 
+    public function testNegateFormulaWithUnreconcilableTerm(): void
+    {
+        $formula = [
+            new Clause(['$a' => ['int']], 1, 1),
+            new Clause(['$b' => ['int']], 1, 2, false, false),
+        ];
+
+        $negated_formula = Algebra::negateFormula($formula);
+
+        $this->assertCount(1, $negated_formula);
+        $this->assertSame(['$a' => ['!int']], $negated_formula[0]->possibilities);
+    }
+
     public function testCombinatorialExpansion(): void
     {
         $dnf = '<?php ($b0 === true && $b4 === true && $b8 === true)

tests/TypeReconciliation/ConditionalTest.php

@@ -2958,6 +2958,22 @@ class ConditionalTest extends \Psalm\Tests\TestCase
                         return $pos;
                     }'
             ],
+            'usedAssertedVarButNotWithStrongerTypeGuarantee' => [
+                '<?php
+                    function broken(bool $b, ?User $u) : void {
+                        if ($b || (rand(0, 1) && (!$u || takesUser($u)))) {
+                            return;
+                        }
+
+                        if ($u) {}
+                    }
+
+                    class User {}
+
+                    function takesUser(User $a) : bool {
+                        return true;
+                    }'
+            ],
         ];
     }