Fix false positives on non-existing-offsets of super-globals

Author: staabm

Diff for: src/Analyser/MutatingScope.php

@@ -548,15 +548,19 @@ public function getVariableType(string $variableName): Type
 			}
 		}
 
+		$varExprString = '$' . $variableName;
 		if ($this->isGlobalVariable($variableName)) {
+			if (array_key_exists($varExprString, $this->expressionTypes)) {
+				return TypeUtils::resolveLateResolvableTypes($this->expressionTypes[$varExprString]->getType());
+			}
+
 			return new ArrayType(new BenevolentUnionType([new IntegerType(), new StringType()]), new MixedType(true));
 		}
 
 		if ($this->hasVariableType($variableName)->no()) {
 			throw new UndefinedVariableException($this, $variableName);
 		}
 
-		$varExprString = '$' . $variableName;
 		if (!array_key_exists($varExprString, $this->expressionTypes)) {
 			return new MixedType();
 		}

Diff for: tests/PHPStan/Analyser/NodeScopeResolverTest.php

@@ -210,6 +210,7 @@ private static function findTestFiles(): iterable
 
 		yield __DIR__ . '/../Rules/Arrays/data/bug-11679.php';
 		yield __DIR__ . '/../Rules/Methods/data/bug-4801.php';
+		yield __DIR__ . '/../Rules/Arrays/data/narrow-superglobal.php';
 	}
 
 	/**

Diff for: tests/PHPStan/Rules/Arrays/NonexistentOffsetInArrayDimFetchRuleTest.php

@@ -870,4 +870,11 @@ public function testBug8649(): void
 		$this->analyse([__DIR__ . '/data/bug-8649.php'], []);
 	}
 
+	public function testNarrowSuperglobals(): void
+	{
+		$this->reportPossiblyNonexistentGeneralArrayOffset = true;
+
+		$this->analyse([__DIR__ . '/data/narrow-superglobal.php'], []);
+	}
+
 }

Diff for: tests/PHPStan/Rules/Arrays/data/narrow-superglobal.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace NarrowsSuperGlobal;
+
+use function PHPStan\Testing\assertType;
+
+class HelloWorld
+{
+	public function doFoo(): void
+	{
+		if (array_key_exists('HTTP_HOST', $_SERVER)) {
+			assertType("non-empty-array&hasOffset('HTTP_HOST')", $_SERVER);
+			echo $_SERVER['HTTP_HOST'];
+		}
+	}
+}