From 3608297e0b8186635b8f52d6c95b16cf6c8f4b7a Mon Sep 17 00:00:00 2001
From: Feoramund <161657516+Feoramund@users.noreply.github.com>
Date: Mon, 23 Jun 2025 09:11:16 -0400
Subject: Forbid nested declaration of instrumentation procedures

Fixes #3774
---
 src/check_decl.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/check_decl.cpp b/src/check_decl.cpp
index 7458f23d5..3d0d95556 100644
--- a/src/check_decl.cpp
+++ b/src/check_decl.cpp
@@ -1341,6 +1341,9 @@ gb_internal void check_proc_decl(CheckerContext *ctx, Entity *e, DeclInfo *d) {
 			error(e->token, "@(instrumentation_enter) procedures must have the type '%s', got %s", instrumentation_proc_type_str, s);
 			gb_string_free(s);
 		}
+		if ((e->scope->flags & (ScopeFlag_File|ScopeFlag_Pkg)) == 0) {
+			error(e->token, "@(instrumentation_enter) procedures must be declared at the file scope");
+		}
 		MUTEX_GUARD(&ctx->info->instrumentation_mutex);
 		if (ctx->info->instrumentation_enter_entity != nullptr) {
 			error(e->token, "@(instrumentation_enter) has already been set");
@@ -1357,6 +1360,9 @@ gb_internal void check_proc_decl(CheckerContext *ctx, Entity *e, DeclInfo *d) {
 			error(e->token, "@(instrumentation_exit) procedures must have the type '%s', got %s", instrumentation_proc_type_str, s);
 			gb_string_free(s);
 		}
+		if ((e->scope->flags & (ScopeFlag_File|ScopeFlag_Pkg)) == 0) {
+			error(e->token, "@(instrumentation_exit) procedures must be declared at the file scope");
+		}
 		MUTEX_GUARD(&ctx->info->instrumentation_mutex);
 		if (ctx->info->instrumentation_exit_entity != nullptr) {
 			error(e->token, "@(instrumentation_exit) has already been set");
-- 
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