Fix infinite recursion

Author: wieslawsoltes

src/ThrowsAnalyzer/Analysis/ExceptionPropagationTracker.cs

@@ -35,11 +35,14 @@ public async Task<ExceptionFlowInfo> AnalyzeMethodAsync(IMethodSymbol method)
 
             var flowInfo = new ExceptionFlowInfo(method);
 
+            // Add placeholder to cache immediately to prevent infinite recursion
+            // in case of circular method calls
+            _cache[method] = flowInfo;
+
             // Find the method's syntax node
             var syntaxReferences = method.DeclaringSyntaxReferences;
             if (!syntaxReferences.Any())
             {
-                _cache[method] = flowInfo;
                 return flowInfo;
             }
 
@@ -59,9 +62,6 @@ public async Task<ExceptionFlowInfo> AnalyzeMethodAsync(IMethodSymbol method)
             // 4. Calculate propagated exceptions (thrown - caught)
             CalculatePropagatedExceptions(flowInfo, semanticModel);
 
-            // Cache the result
-            _cache[method] = flowInfo;
-
             return flowInfo;
         }