From a99e4b602a25f7ded5f53fea2525c300b011d765 Mon Sep 17 00:00:00 2001
From: Christoffer Lerno <christoffer@aegik.com>
Date: Fri, 27 Sep 2024 13:10:48 +0200
Subject: [PATCH] Error when slicing a struct with an inline array #1488.

---
 releasenotes.md                         |  1 +
 src/compiler/sema_expr.c                |  5 +++-
 test/test_suite/slices/slice_inline.c3t | 34 +++++++++++++++++++++++++
 3 files changed, 39 insertions(+), 1 deletion(-)
 create mode 100644 test/test_suite/slices/slice_inline.c3t

diff --git a/releasenotes.md b/releasenotes.md
index 6e0029a86..3a26d7216 100644
--- a/releasenotes.md
+++ b/releasenotes.md
@@ -62,6 +62,7 @@
 - Regression when compile time accessing a union field not last assigned to.
 - Safer seed of rand() for WASM without libc.
 - Bad error message aliasing an ident with a path. #1481.
+- Error when slicing a struct with an inline array #1488.
 
 ### Stdlib changes
 - Additional init functions for hashmap.
diff --git a/src/compiler/sema_expr.c b/src/compiler/sema_expr.c
index bf9249d1e..971e63532 100644
--- a/src/compiler/sema_expr.c
+++ b/src/compiler/sema_expr.c
@@ -3357,13 +3357,16 @@ static inline bool sema_expr_analyse_slice(SemaContext *context, Expr *expr, Che
 	}
 	Expr *current_expr = subscripted;
 	Type *inner_type = sema_subscript_find_indexable_type_recursively(&type, &current_expr);
-
 	if (type == type_voidptr) inner_type = type_char;
 
 	if (!inner_type || !type_is_valid_for_array(inner_type))
 	{
 		RETURN_SEMA_ERROR(subscripted, "Cannot index %s.", type_quoted_error_string(subscripted->type));
 	}
+	if (current_expr != subscripted)
+	{
+		expr->slice_expr.expr = exprid(current_expr);
+	}
 	// Retain the original type when doing distinct slices.
 	Type *result_type = type_get_slice(inner_type);
 	Type *original_type_canonical = original_type->canonical;
diff --git a/test/test_suite/slices/slice_inline.c3t b/test/test_suite/slices/slice_inline.c3t
new file mode 100644
index 000000000..5e395737f
--- /dev/null
+++ b/test/test_suite/slices/slice_inline.c3t
@@ -0,0 +1,34 @@
+// #target: macos-x64
+module foo;
+struct Data{
+    inline char[32] data;
+}
+fn void Data.not_working(self) {
+    self[:self.data.len];
+}
+
+fn void Data.working(self) {
+    self.data[:self.data.len];
+}
+fn void! main(String[] args) {
+    Data d;
+    d.not_working();
+    d.working();
+}
+
+/* #expect: foo.ll
+
+define void @foo.Data.not_working(ptr byval(%Data) align 8 %0) #0 {
+entry:
+  %1 = insertvalue %"char[]" undef, ptr %0, 0
+  %2 = insertvalue %"char[]" %1, i64 32, 1
+  ret void
+}
+; Function Attrs: nounwind uwtable
+define void @foo.Data.working(ptr byval(%Data) align 8 %0) #0 {
+entry:
+  %1 = insertvalue %"char[]" undef, ptr %0, 0
+  %2 = insertvalue %"char[]" %1, i64 32, 1
+  ret void
+}
+