rebuilt changes in checker

Author: nicolas377

src/compiler/checker.ts

@@ -27275,6 +27275,8 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         const isOuterVariable = flowContainer !== declarationContainer;
         const isSpreadDestructuringAssignmentTarget = node.parent && node.parent.parent && isSpreadAssignment(node.parent) && isDestructuringAssignmentTarget(node.parent.parent);
         const isModuleExports = symbol.flags & SymbolFlags.ModuleExports;
+        const typeIsAutomatic = type === autoType || type === autoArrayType;
+        const isAutomaticTypeInNonNull = typeIsAutomatic && node.parent.kind === SyntaxKind.NonNullExpression;
         // When the control flow originates in a function expression or arrow function and we are referencing
         // a const variable or parameter from an outer function, we extend the origin of the control flow
         // analysis to include the immediately enclosing function.
@@ -27292,10 +27294,11 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
             node.parent.kind === SyntaxKind.NonNullExpression ||
             declaration.kind === SyntaxKind.VariableDeclaration && (declaration as VariableDeclaration).exclamationToken ||
             declaration.flags & NodeFlags.Ambient;
-        const initialType = assumeInitialized ? (isParameter ? removeOptionalityFromDeclaredType(type, declaration as VariableLikeDeclaration) : type) :
-            type === autoType || type === autoArrayType ? undefinedType :
-            getOptionalType(type);
-        const flowType = getFlowTypeOfReference(node, type, initialType, flowContainer);
+        const initialType = isAutomaticTypeInNonNull ? undefinedType :
+            assumeInitialized ? (isParameter ? removeOptionalityFromDeclaredType(type, declaration as VariableLikeDeclaration) : type) :
+            typeIsAutomatic ? undefinedType : getOptionalType(type);
+        const flowType = isAutomaticTypeInNonNull ? getNonNullableType(getFlowTypeOfReference(node, type, initialType, flowContainer)) :
+            getFlowTypeOfReference(node, type, initialType, flowContainer);
         // A variable is considered uninitialized when it is possible to analyze the entire control flow graph
         // from declaration to use, and when the variable's declared type doesn't include undefined but the
         // control flow based type does include undefined.