Infer type from known ternary condition.

vimeo · Dec 13, 2021 · 49599d2 · 49599d2
1 parent df7d1eb
commit 49599d2
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Showing 2 changed files with 9 additions and 5 deletions.
diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/TernaryAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Expression/TernaryAnalyzer.php
@@ -274,12 +274,12 @@ function ($c) use ($reconciled_expression_clauses): bool {
         );
 
         $lhs_type = null;
-
+        $stmt_cond_type = $statements_analyzer->node_data->getType($stmt->cond);
         if ($stmt->if) {
             if ($stmt_if_type = $statements_analyzer->node_data->getType($stmt->if)) {
                 $lhs_type = $stmt_if_type;
             }
-        } elseif ($stmt_cond_type = $statements_analyzer->node_data->getType($stmt->cond)) {
+        } elseif ($stmt_cond_type) {
             $if_return_type_reconciled = AssertionReconciler::reconcile(
                 '!falsy',
                 clone $stmt_cond_type,
@@ -295,7 +295,13 @@ function ($c) use ($reconciled_expression_clauses): bool {
         }
 
         if ($lhs_type && ($stmt_else_type = $statements_analyzer->node_data->getType($stmt->else))) {
-            $statements_analyzer->node_data->setType($stmt, Type::combineUnionTypes($lhs_type, $stmt_else_type));
+            if ($stmt_cond_type !== null && $stmt_cond_type->isAlwaysFalsy()) {
+                $statements_analyzer->node_data->setType($stmt, $stmt_else_type);
+            } elseif ($stmt_cond_type !== null && $stmt_cond_type->isAlwaysTruthy()) {
+                $statements_analyzer->node_data->setType($stmt, $lhs_type);
+            } else {
+                $statements_analyzer->node_data->setType($stmt, Type::combineUnionTypes($lhs_type, $stmt_else_type));
+            }
         } else {
             $statements_analyzer->node_data->setType($stmt, Type::getMixed());
         }

diff --git a/tests/ConstantTest.php b/tests/ConstantTest.php
@@ -618,8 +618,6 @@ class B extends A {
 
                     class Clazz {
                         /**
-                         * @var 0|1
-                         *
                          * @psalm-suppress RedundantCondition
                          */
                         const cons2 = (cons1) ? 1 : 0;