From 387990c82c57bc8ca2121685b3d2a2df79f3f170 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20Petryka?=
 <35800402+MichalPetryka@users.noreply.github.com>
Date: Sat, 11 Apr 2026 15:56:36 +0200
Subject: [PATCH 1/2] Improve debugger message for scanner failures

Makes the assert use the full message used by the exception.
---
 .../tools/aot/ILCompiler.Compiler/Compiler/ILScanner.cs      | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ILScanner.cs b/src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ILScanner.cs
index 3c2c08c0005c33..c5b6d98da5b9a8 100644
--- a/src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ILScanner.cs
+++ b/src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ILScanner.cs
@@ -433,8 +433,9 @@ private PrecomputedDictionaryLayoutNode GetPrecomputedLayout(TypeSystemEntity me
                     // On the path, you'll find a node that exists in both graphs, but it's predecessor
                     // only exists in the compiler's graph. That's the place to focus the investigation on.
                     // Use the ILCompiler-DependencyGraph-Viewer tool to investigate.
-                    Debug.Assert(false);
-                    throw new ScannerFailedException($"Dictionary layout of '{methodOrType}' was not computed by the IL scanner.");
+                    string message = $"Dictionary layout of '{methodOrType}' was not computed by the IL scanner.";
+                    Debug.Fail(message);
+                    throw new ScannerFailedException(message);
                 }
                 return new PrecomputedDictionaryLayoutNode(methodOrType, layout.Slots, layout.DiscardedSlots);
             }

From 775f08d8a954d623f477c9cca2866e9947f427e8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20Petryka?=
 <35800402+MichalPetryka@users.noreply.github.com>
Date: Sat, 18 Apr 2026 01:31:09 +0200
Subject: [PATCH 2/2] Remove Debug.Assert and Debug.Fail statements

---
 .../tools/aot/ILCompiler.Compiler/Compiler/ILScanner.cs      | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ILScanner.cs b/src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ILScanner.cs
index c5b6d98da5b9a8..663125672b1af8 100644
--- a/src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ILScanner.cs
+++ b/src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/ILScanner.cs
@@ -331,7 +331,6 @@ internal override VTableSliceNode GetSlice(TypeDesc type)
                         // On the path, you'll find a node that exists in both graphs, but it's predecessor
                         // only exists in the compiler's graph. That's the place to focus the investigation on.
                         // Use the ILCompiler-DependencyGraph-Viewer tool to investigate.
-                        Debug.Assert(false);
                         string typeName = ExceptionTypeNameFormatter.Instance.FormatName(type);
                         throw new ScannerFailedException($"VTable of type '{typeName}' not computed by the IL scanner.");
                     }
@@ -433,9 +432,7 @@ private PrecomputedDictionaryLayoutNode GetPrecomputedLayout(TypeSystemEntity me
                     // On the path, you'll find a node that exists in both graphs, but it's predecessor
                     // only exists in the compiler's graph. That's the place to focus the investigation on.
                     // Use the ILCompiler-DependencyGraph-Viewer tool to investigate.
-                    string message = $"Dictionary layout of '{methodOrType}' was not computed by the IL scanner.";
-                    Debug.Fail(message);
-                    throw new ScannerFailedException(message);
+                    throw new ScannerFailedException($"Dictionary layout of '{methodOrType}' was not computed by the IL scanner.");
                 }
                 return new PrecomputedDictionaryLayoutNode(methodOrType, layout.Slots, layout.DiscardedSlots);
             }