Implement InterpolatedStringHandler

src/Analyser/Generator/ExprHandler/InterpolatedStringHandler.php

@@ -0,0 +1,90 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Analyser\Generator\ExprHandler;
+
+use Generator;
+use PhpParser\Node\Expr;
+use PhpParser\Node\InterpolatedStringPart;
+use PhpParser\Node\Scalar\InterpolatedString;
+use PhpParser\Node\Stmt;
+use PHPStan\Analyser\ExpressionContext;
+use PHPStan\Analyser\Generator\ExprAnalysisRequest;
+use PHPStan\Analyser\Generator\ExprAnalysisResult;
+use PHPStan\Analyser\Generator\ExprHandler;
+use PHPStan\Analyser\Generator\GeneratorScope;
+use PHPStan\Analyser\Generator\NoopNodeCallback;
+use PHPStan\Analyser\SpecifiedTypes;
+use PHPStan\DependencyInjection\AutowiredService;
+use PHPStan\Reflection\InitializerExprTypeResolver;
+use PHPStan\Type\Constant\ConstantStringType;
+use function array_merge;
+
+/**
+ * @implements ExprHandler<InterpolatedString>
+ */
+#[AutowiredService]
+final class InterpolatedStringHandler implements ExprHandler
+{
+
+	public function __construct(private InitializerExprTypeResolver $initializerExprTypeResolver)
+	{
+	}
+
+	public function supports(Expr $expr): bool
+	{
+		return $expr instanceof InterpolatedString;
+	}
+
+	public function analyseExpr(
+		Stmt $stmt,
+		Expr $expr,
+		GeneratorScope $scope,
+		ExpressionContext $context,
+		?callable $alternativeNodeCallback,
+	): Generator
+	{
+		yield from [];
+
+		$resultType = null;
+		$hasYield = false;
+		$throwPoints = [];
+		$impurePoints = [];
+		$isAlwaysTerminating = false;
+		foreach ($expr->parts as $part) {
+			if ($part instanceof InterpolatedStringPart) {
+				$partType = new ConstantStringType($part->value);
+			} else {
+				$result = yield new ExprAnalysisRequest($stmt, $part, $scope, $context->enterDeep(), new NoopNodeCallback());
+				$partType = $result->type->toString();
+
+				$hasYield = $hasYield || $result->hasYield;
+				$throwPoints = array_merge($throwPoints, $result->throwPoints);
+				$impurePoints = array_merge($impurePoints, $result->impurePoints);
+				$isAlwaysTerminating = $isAlwaysTerminating || $result->isAlwaysTerminating;
+				$scope = $result->scope;
+			}
+
+			if ($resultType === null) {
+				$resultType = $partType;
+				continue;
+			}
+
+			$resultType = $this->initializerExprTypeResolver->resolveConcatType($resultType, $partType);
+		}
+
+		$type = $resultType ?? new ConstantStringType('');
+		return new ExprAnalysisResult(
+			$type,
+			$type,
+			$scope,
+			hasYield: $hasYield,
+			isAlwaysTerminating: $isAlwaysTerminating,
+			throwPoints: $throwPoints,
+			impurePoints: $impurePoints,
+			specifiedTruthyTypes: new SpecifiedTypes(),
+			specifiedFalseyTypes: new SpecifiedTypes(),
+			specifiedNullTypes: new SpecifiedTypes(),
+		);
+	}
+
+}

tests/PHPStan/Analyser/Generator/data/gnsr.php

@@ -247,6 +247,14 @@ function doCast() {
 		assertType("'1'", (string) $a);
 	}
 
+	function doInterpolatedString() {
+		$a = '1';
+
+		assertType("'1'", "$a");
+		assertNativeType("'1'", "$a");
+	}
+
+
 }
 
 function (): void {