From 0a424ec6d2d54bd424f069bbbca2186b529579c5 Mon Sep 17 00:00:00 2001
From: hl-valdemar <valdemar.lorenzen@icloud.com>
Date: Sun, 12 Jul 2026 21:02:12 +0200
Subject: [PATCH] mem.eql (stdlib)

---
 LANGUAGE.md                              |  2 +-
 TODO.md                                  |  2 +-
 compiler/checker/checker.odin            | 14 ++++++++++++++
 examples/programs/mem_allocator/main.bro | 21 +++++++++++++++++++++
 std/mem/mem.bro                          | 14 ++++++++++++++
 5 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/LANGUAGE.md b/LANGUAGE.md
index adcc71c..2e573fe 100644
--- a/LANGUAGE.md
+++ b/LANGUAGE.md
@@ -77,7 +77,7 @@ roadmap and milestone history.
 
 ### standard packages
 
-- `std/mem` allocator contract with raw byte operations, typed `empty` / `alloc` / `realloc` / `free`, overflow checks, zero-sized-type support, and failure-preserving reallocation
+- `std/mem` generic slice equality, allocator contract with raw byte operations, typed `empty` / `alloc` / `realloc` / `free`, overflow checks, zero-sized-type support, and failure-preserving reallocation
 - `std/arraylist` generic `ArrayList(T)` with direct `items` slice access, explicit capacity, allocator ownership, fallible reserve/append, clear, and deinit
 
 ### compiler behavior
diff --git a/TODO.md b/TODO.md
index e4362e3..bb47574 100644
--- a/TODO.md
+++ b/TODO.md
@@ -794,7 +794,7 @@
 32. disallow arbitrary integer division
   - take inspiration from zig
   - see also below for a word on unchecked casts
-  - the user should be explicit about what they mean with integer division (e.g. `div`, `rem`, `trunc`)
+  - the user should be explicit about what they mean with integer division (e.g. `div`, `rem`)
 
 ## A word on unchecked casts
 
diff --git a/compiler/checker/checker.odin b/compiler/checker/checker.odin
index 915b457..8e13a20 100644
--- a/compiler/checker/checker.odin
+++ b/compiler/checker/checker.odin
@@ -1350,6 +1350,20 @@ match_inferred_type_pattern :: proc(
 		return matched
 	}
 	actual_item, actual_ok := types.node(store, actual_type)
+	if pattern_item.kind == .Slice {
+		actual_pointer, actual_array, array_pointer_ok := types.array_pointer(actual_type, store)
+		if array_pointer_ok {
+			mutable := actual_pointer.mutable && actual_array.mutable
+			if pattern_item.mutable && !mutable ||
+			   pattern_item.has_sentinel && (!actual_array.has_sentinel || pattern_item.sentinel != actual_array.sentinel) {
+				return false
+			}
+			return match_inferred_type_pattern(
+				checker, function, prefix, pattern_item.child, actual_array.child,
+				values, bound, span, diagnose, depth+1,
+			)
+		}
+	}
 	if !actual_ok || pattern_item.kind != actual_item.kind {
 		resolved := type_from_syntax(checker, pattern, function.pkg, function.file)
 		return types.is_valid(resolved) && types.equal(types.resolve_alias(resolved, store), actual_type)
diff --git a/examples/programs/mem_allocator/main.bro b/examples/programs/mem_allocator/main.bro
index 9cca642..8a6bdc4 100644
--- a/examples/programs/mem_allocator/main.bro
+++ b/examples/programs/mem_allocator/main.bro
@@ -1,4 +1,25 @@
+mem :: import "@std/mem"
+
+eql_test func() i32 {
+	if (mem.eql("bro", "bro") == false) return 21
+	if mem.eql("bro", "bra") return 22
+	if mem.eql("bro", "brolang") return 23
+
+	empty []u8 :: ""
+	if (mem.eql(empty, "") == false) return 24
+
+	left [3]i32 :: [1, 2, 3]
+	same [3]i32 :: [1, 2, 3]
+	different [3]i32 :: [1, 2, 4]
+	if (mem.eql(left[..], same[..]) == false) return 25
+	if mem.eql(left[..], different[..]) return 26
+	return 0
+}
+
 main func() i32 {
+	eql_result i32 :: eql_test()
+	if (eql_result != 0) return eql_result
+
 	typed_result i32 :: typed_allocator_test()
 	if (typed_result != 0) return typed_result
 
diff --git a/std/mem/mem.bro b/std/mem/mem.bro
index 2cc32c3..2f3ad18 100644
--- a/std/mem/mem.bro
+++ b/std/mem/mem.bro
@@ -27,6 +27,20 @@ raw_free func(allocator Allocator, memory ?*mut u8, size usize, alignment usize)
 	allocator.vtable.free(allocator.context, memory, size, alignment)
 }
 
+eql func($T type, left, right []T) bool {
+	if left.len != right.len {
+		return false
+	}
+
+	i usize = 0
+	while i < left.len : i += 1 {
+		if left[i] != right[i] {
+			return false
+		}
+	}
+	return true
+}
+
 _empty_storage [1]mut u64 = [0]
 
 _empty_slice func($T type, count usize) []mut T {