Fix phpstan/phpstan#11129: concat of numeric constant string and int should lead to numeric-string

phpstan-baseline.neon

@@ -435,24 +435,6 @@ parameters:
 			count: 1
 			path: src/Reflection/InitializerExprTypeResolver.php
 
-		-
-			rawMessage: Binary operation "*" between bool|float|int|string|null and bool|float|int|string|null results in an error.
-			identifier: binaryOp.invalid
-			count: 1
-			path: src/Reflection/InitializerExprTypeResolver.php
-
-		-
-			rawMessage: Binary operation "+" between bool|float|int|string|null and bool|float|int|string|null results in an error.
-			identifier: binaryOp.invalid
-			count: 1
-			path: src/Reflection/InitializerExprTypeResolver.php
-
-		-
-			rawMessage: Binary operation "-" between bool|float|int|string|null and bool|float|int|string|null results in an error.
-			identifier: binaryOp.invalid
-			count: 1
-			path: src/Reflection/InitializerExprTypeResolver.php
-
 		-
 			rawMessage: Binary operation "^" between bool|float|int|string|null and bool|float|int|string|null results in an error.
 			identifier: binaryOp.invalid

src/Reflection/InitializerExprTypeResolver.php

@@ -1288,7 +1288,7 @@
 							return new ErrorType();
 						}
 
-						$resultType = $this->getTypeFromValue($leftNumberType->getValue() / $rightNumberType->getValue()); // @phpstan-ignore binaryOp.invalid
+						$resultType = $this->getTypeFromValue($leftNumberType->getValue() / $rightNumberType->getValue());
 						$resultTypes[] = $resultType;
 					}
 				}
@@ -2119,6 +2119,13 @@
 			return new ErrorType();
 		}
 
+		if ($leftNumberType instanceof ErrorType) {
+			$leftNumberType = $this->filterNumberTypeFromUnion($leftType) ?? $leftNumberType;
+		}
+		if ($rightNumberType instanceof ErrorType) {
+			$rightNumberType = $this->filterNumberTypeFromUnion($rightType) ?? $rightNumberType;
+		}
+
 		if ($leftNumberType instanceof ErrorType || $rightNumberType instanceof ErrorType) {
 			return new ErrorType();
 		}
@@ -2155,6 +2162,39 @@
 		return $resultType;
 	}
 
+	/**
+	 * When toNumber() on a union returns ErrorType because some members (strings)
+	 * can't be proven numeric, try to extract the numeric parts.
+	 * Only skips ErrorType from string members, since string-to-number conversion
+	 * always produces a result in PHP (with possible deprecation warning).
+	 */
+	private function filterNumberTypeFromUnion(Type $type): ?Type
+	{
+		if (!$type instanceof UnionType) {
+			return null;
+		}
+
+		$numberTypes = [];
+		$hasSkipped = false;
+		foreach ($type->getTypes() as $memberType) {
+			$numberType = $memberType->toNumber();
+			if ($numberType instanceof ErrorType) {
+				if ($memberType->isString()->yes()) {
+					$hasSkipped = true;
+					continue;
+				}
+				return null;
+			}
+			$numberTypes[] = $numberType;
+		}
+
+		if ($numberTypes === [] || !$hasSkipped) {
+			return null;
+		}
+
+		return TypeCombinator::union(...$numberTypes);
+	}
+
 	/**
 	 * @param ConstantIntegerType|IntegerRangeType $range
 	 * @param BinaryOp\Div|BinaryOp\Minus|BinaryOp\Mul|BinaryOp\Plus|BinaryOp\ShiftLeft|BinaryOp\ShiftRight $node

tests/PHPStan/Analyser/nsrt/bug-11129b.php

@@ -0,0 +1,36 @@
+<?php declare(strict_types = 1);
+
+namespace Bug11129b;
+
+use function PHPStan\Testing\assertType;
+
+class HelloWorld
+{
+	/** @param array<string> $array */
+	public function sayHello(array $array): void
+	{
+		$pos = 0;
+		foreach ($array as $element) {
+			++$pos;
+
+			if ($pos < 10) {
+				$pos = '0' . $pos;
+			}
+		}
+		assertType('0|float|(non-falsy-string&uppercase-string)', $pos);
+	}
+
+	/** @param array<string> $array */
+	public function withPlusOne(array $array): void
+	{
+		$pos = 0;
+		foreach ($array as $element) {
+			$pos = $pos + 1;
+
+			if ($pos < 10) {
+				$pos = '0' . $pos;
+			}
+		}
+		assertType('0|float|(non-falsy-string&uppercase-string)', $pos);
+	}
+}