From 182b05e73b59a5aefe397740094a74526b99c070 Mon Sep 17 00:00:00 2001
From: Anthony Martin <38542602+anthony-c-martin@users.noreply.github.com>
Date: Tue, 5 Mar 2024 09:23:12 -0500
Subject: [PATCH] Fix for issue 13531 (#13532)

Closes #13531
###### Microsoft Reviewers: [Open in
CodeFlow](https://microsoft.github.io/open-pr/?codeflow=https://github.com/Azure/bicep/pull/13532)
---
 .../ScenarioTests.cs                          | 21 +++++++++++++++++++
 .../Emit/EmitLimitationCalculator.cs          | 14 ++++++-------
 2 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/src/Bicep.Core.IntegrationTests/ScenarioTests.cs b/src/Bicep.Core.IntegrationTests/ScenarioTests.cs
index c1da621a361..30bc0192f1a 100644
--- a/src/Bicep.Core.IntegrationTests/ScenarioTests.cs
+++ b/src/Bicep.Core.IntegrationTests/ScenarioTests.cs
@@ -5622,6 +5622,27 @@ public void Test_Issue12908()
         });
     }
 
+    // https://github.com/Azure/bicep/issues/13531
+    [TestMethod]
+    public void Test_Issue13531()
+    {
+        var result = CompilationHelper.CompileParams(
+            ("parameters.bicepparam", """
+using 'main.bicep'
+
+param location = location
+"""),
+            ("main.bicep", """
+#disable-next-line no-unused-params
+param location string
+"""));
+
+        result.Should().HaveDiagnostics(new[]
+        {
+            ("BCP079", DiagnosticLevel.Error, """This expression is referencing its own declaration, which is not allowed."""),
+        });
+    }
+
     [TestMethod]
     public void Functions_can_be_imported_in_bicepparam_files()
     {
diff --git a/src/Bicep.Core/Emit/EmitLimitationCalculator.cs b/src/Bicep.Core/Emit/EmitLimitationCalculator.cs
index 6acf40f6a2a..1ca90630f75 100644
--- a/src/Bicep.Core/Emit/EmitLimitationCalculator.cs
+++ b/src/Bicep.Core/Emit/EmitLimitationCalculator.cs
@@ -513,6 +513,13 @@ private static void BlockCyclicAggregateTypeReferences(SemanticModel model, IDia
 
             foreach (var symbol in GetTopologicallySortedSymbols(referencesInValues))
             {
+                if (symbol.Type is ErrorType)
+                {
+                    // no point evaluating if we're already reporting an error
+                    erroredSymbols.Add(symbol);
+                    continue;
+                }
+
                 var referencedValueHasError = false;
                 foreach (var referenced in referencesInValues[symbol])
                 {
@@ -547,13 +554,6 @@ private static void BlockCyclicAggregateTypeReferences(SemanticModel model, IDia
                     continue;
                 }
 
-                if (parameter.Type is ErrorType)
-                {
-                    // no point evaluating if we're already reporting an error
-                    erroredSymbols.Add(parameter);
-                    continue;
-                }
-
                 // We may emit duplicate errors here - type checking will also execute some ARM functions and generate errors
                 // This is something we should improve before the first release.
                 var result = evaluator.EvaluateParameter(parameter);