infer non-empty-string on literal-string and strlen()

Author: staabm

src/Analyser/TypeSpecifier.php

@@ -235,7 +235,7 @@ public function specifyTypesInCondition(
 							$newContext = $newContext->negate();
 						}
 						$argType = $scope->getType($exprNode->getArgs()[0]->value);
-						if ($argType instanceof StringType) {
+						if ($argType->isString()->yes()) {
 							$funcTypes = $this->create($exprNode, $constantType, $context, false, $scope, $rootExpr);
 							$valueTypes = $this->create($exprNode->getArgs()[0]->value, new AccessoryNonEmptyStringType(), $newContext, false, $scope, $rootExpr);
 							return $funcTypes->unionWith($valueTypes);
@@ -535,7 +535,7 @@ public function specifyTypesInCondition(
 					|| ($context->falsey() && (new ConstantIntegerType(1 - $offset))->isSuperTypeOf($leftType)->yes())
 				) {
 					$argType = $scope->getType($expr->right->getArgs()[0]->value);
-					if ($argType instanceof StringType) {
+					if ($argType->isString()->yes()) {
 						$result = $result->unionWith($this->create($expr->right->getArgs()[0]->value, new AccessoryNonEmptyStringType(), $context, false, $scope, $rootExpr));
 					}
 				}

tests/PHPStan/Analyser/data/non-empty-string.php

@@ -89,6 +89,30 @@ public function doBar5(string $s): void
 		assertType('\'\'', $s);
 	}
 
+	/**
+	 * @param literal-string $s
+	 */
+	public function doBar6($s): void
+	{
+		if (1 === strlen($s)) {
+			assertType('literal-string&non-empty-string', $s);
+			return;
+		}
+		assertType('literal-string', $s);
+	}
+
+	/**
+	 * @param literal-string $s
+	 */
+	public function doBar7($s): void
+	{
+		if (0 < strlen($s)) {
+			assertType('literal-string&non-empty-string', $s);
+			return;
+		}
+		assertType("''", $s);
+	}
+
 	public function doFoo3(string $s): void
 	{
 		if ($s) {