Name the guarded API in ThrowIfVerifyHasBeenRun

src/Verify.Tests/ThrowIfVerifyHasBeenRunTests.cs

@@ -0,0 +1,23 @@
+public class ThrowIfVerifyHasBeenRunTests
+{
+    // The message points at the API that must move to a module initializer, so it has to
+    // name that API and not the code that called it
+    [Fact]
+    public void NamesTheApi()
+    {
+        var original = InnerVerifier.verifyHasBeenRun;
+        InnerVerifier.verifyHasBeenRun = true;
+        try
+        {
+            var exception = Assert.Throws<Exception>(
+                () => VerifierSettings.IgnoreMembers<string>("TheMember"));
+
+            Assert.Contains("The API 'IgnoreMembers'", exception.Message);
+            Assert.DoesNotContain(nameof(NamesTheApi), exception.Message);
+        }
+        finally
+        {
+            InnerVerifier.verifyHasBeenRun = original;
+        }
+    }
+}

src/Verify/Verifier/InnerVerifier.cs

@@ -1,5 +1,3 @@
-using StackTrace = System.Diagnostics.StackTrace;
-
 namespace VerifyTests;
 
 public partial class InnerVerifier :
@@ -24,18 +22,20 @@ public partial class InnerVerifier :
     // inline is not compatible with.
     string? pathPrefixReceived;
 
-    [MethodImpl(MethodImplOptions.NoInlining)]
-    public static void ThrowIfVerifyHasBeenRun()
+    /// <param name="api">
+    /// Defaulted from the calling member, so it names the API that has the restriction.
+    /// Reading it off a StackTrace instead only works while that API has a frame of its
+    /// own: the JIT is free to inline it into the caller, and does on net48 in release,
+    /// which put the caller's name in the message.
+    /// </param>
+    public static void ThrowIfVerifyHasBeenRun([CallerMemberName] string api = "")
     {
         if (!verifyHasBeenRun)
         {
             return;
         }
 
-        var stackTrace = new StackTrace(1, false);
-        var method = stackTrace.GetFrame(1)!.GetMethod()!;
-        var type = method.DeclaringType;
-        throw new($"The API '{type}.{method.Name}' must be called prior to any Verify has run. Usually this is done in a [ModuleInitializer]. Verify run by: {verifyHasBeenRunBy}");
+        throw new($"The API '{api}' must be called prior to any Verify has run. Usually this is done in a [ModuleInitializer]. Verify run by: {verifyHasBeenRunBy}");
     }
 
     public InnerVerifier(

src/todo.md

@@ -56,7 +56,7 @@ All six resolved 2026-08-16 (five fixed here; the inline item resolved as by-des
 - [x] **`Delete:` section drops subdirectories, breaking the parse round-trip.**
   `Verify/Verifier/VerifyExceptionMessageBuilder.cs:62` emits `Path.GetFileName(file)` while the other sections emit directory-relative paths, and `Verify.ExceptionParsing/Parser.cs:109` reconstructs with `Path.Combine(directory, name)`. For `UseUniqueDirectory()`/`VerifyDirectory` tests, a stale `{Directory}\Type.Method\old.verified.txt` parses back as the nonexistent `{Directory}\old.verified.txt`; same-named files in different subdirectories collapse.
 
-- [ ] **`ThrowIfVerifyHasBeenRun` blames the caller instead of the API.**
+- [x] **`ThrowIfVerifyHasBeenRun` blames the caller instead of the API.**
   `Verify/Verifier/InnerVerifier.cs:35-38` — `new StackTrace(1, false)` already skips the guard, so frame 0 is the guarded API; `GetFrame(1)` fetches the API's caller. The message names the user's own method as "The API". Runtime-reproduced (Debug and Release). Fix: `GetFrame(0)`.
 
 ## Minor / edge cases