From 967f14148f8da7e9ede53e64ebdd0ca58086f2e8 Mon Sep 17 00:00:00 2001
From: Christoffer Lerno <christoffer@aegik.com>
Date: Thu, 10 Oct 2024 13:42:12 +0200
Subject: [PATCH] Bug when defers and $if were combined in a macro, which would
 cause miscompilation.

---
 releasenotes.md                               |  1 +
 src/compiler/sema_stmts.c                     |  2 +-
 test/test_suite/compile_time/ct_if.c3t        |  1 +
 .../test_suite/compile_time/ct_if_folding.c3t | 32 +++++++++++++++++++
 4 files changed, 35 insertions(+), 1 deletion(-)
 create mode 100644 test/test_suite/compile_time/ct_if_folding.c3t

diff --git a/releasenotes.md b/releasenotes.md
index fe2d0e26c..8836c3e9f 100644
--- a/releasenotes.md
+++ b/releasenotes.md
@@ -21,6 +21,7 @@
 - Fix broken sincos function.
 - Bug when a continue is copied in a defer.
 - Compiler error when any/interface initialized using {} #1533.
+- Bug when defers and $if were combined in a macro, which would cause miscompilation.
 
 ### Stdlib changes
 - Remove unintended print of `char[]` as String
diff --git a/src/compiler/sema_stmts.c b/src/compiler/sema_stmts.c
index db0556cbd..d1e786d68 100644
--- a/src/compiler/sema_stmts.c
+++ b/src/compiler/sema_stmts.c
@@ -2148,7 +2148,7 @@ static inline bool sema_analyse_compound_statement_no_scope(SemaContext *context
 			all_ok = false;
 		}
 	}
-	AstId *next = ast ? &ast->next : &compound_statement->compound_stmt.first_stmt;
+	AstId *next = ast ? &ast_last(ast)->next : &compound_statement->compound_stmt.first_stmt;
 	context_pop_defers(context, next);
 	return all_ok;
 }
diff --git a/test/test_suite/compile_time/ct_if.c3t b/test/test_suite/compile_time/ct_if.c3t
index 8770f2e24..fe7b39df6 100644
--- a/test/test_suite/compile_time/ct_if.c3t
+++ b/test/test_suite/compile_time/ct_if.c3t
@@ -1,3 +1,4 @@
+// #target: macos-x64
 int x @if(false) = 1;
 
 int d @if(true) = 5;
diff --git a/test/test_suite/compile_time/ct_if_folding.c3t b/test/test_suite/compile_time/ct_if_folding.c3t
new file mode 100644
index 000000000..97126d475
--- /dev/null
+++ b/test/test_suite/compile_time/ct_if_folding.c3t
@@ -0,0 +1,32 @@
+// #target: macos-x64
+module test;
+
+macro void @test(bool $skip = false)
+{
+	$if $skip:
+
+	$else
+	int a;
+	int b;
+	defer
+	{
+		a = b;
+	}
+	$endif
+}
+
+fn int main() {
+	@test();
+    return 0;
+}
+/* #expect: test.ll
+
+entry:
+  %a = alloca i32, align 4
+  %b = alloca i32, align 4
+  store i32 0, ptr %a, align 4
+  store i32 0, ptr %b, align 4
+  %0 = load i32, ptr %b, align 4
+  store i32 %0, ptr %a, align 4
+  ret i32 0
+}