implement error when assigning to field of const struct

closes #48

4 files changed, 17 insertions, 5 deletions

diff --git a/src/ir.cpp b/src/ir.cpp
index 98d56de989..f6b932a9e7 100644
--- a/src/ir.cpp
+++ b/src/ir.cpp
@@ -8423,6 +8423,8 @@ static TypeTableEntry *ir_analyze_container_field_ptr(IrAnalyze *ira, Buf *field
     TypeTableEntry *bare_type = container_ref_type(container_type);
     ensure_complete_type(ira->codegen, bare_type);
 
+    assert(container_ptr->value.type->id == TypeTableEntryIdPointer);
+    bool is_const = container_ptr->value.type->data.pointer.is_const;
     if (bare_type->id == TypeTableEntryIdStruct) {
         if (bare_type->data.structure.is_invalid)
             return ira->codegen->builtin_types.entry_invalid;
@@ -8430,7 +8432,7 @@ static TypeTableEntry *ir_analyze_container_field_ptr(IrAnalyze *ira, Buf *field
         TypeStructField *field = find_struct_type_field(bare_type, field_name);
         if (field) {
             ir_build_struct_field_ptr_from(&ira->new_irb, &field_ptr_instruction->base, container_ptr, field);
-            return get_pointer_to_type(ira->codegen, field->type_entry, false);
+            return get_pointer_to_type(ira->codegen, field->type_entry, is_const);
         } else {
             return ir_analyze_container_member_access_inner(ira, bare_type, field_name,
                 field_ptr_instruction, container_ptr, container_type);
@@ -8442,7 +8444,7 @@ static TypeTableEntry *ir_analyze_container_field_ptr(IrAnalyze *ira, Buf *field
         TypeEnumField *field = find_enum_type_field(bare_type, field_name);
         if (field) {
             ir_build_enum_field_ptr_from(&ira->new_irb, &field_ptr_instruction->base, container_ptr, field);
-            return get_pointer_to_type(ira->codegen, field->type_entry, false);
+            return get_pointer_to_type(ira->codegen, field->type_entry, is_const);
         } else {
             return ir_analyze_container_member_access_inner(ira, bare_type, field_name,
                 field_ptr_instruction, container_ptr, container_type);
diff --git a/std/debug.zig b/std/debug.zig
index a5213dfbea..ba43dba83d 100644
--- a/std/debug.zig
+++ b/std/debug.zig
@@ -327,8 +327,8 @@ fn parseAbbrevTable(in_stream: &io.InStream) -> %AbbrevTable {
 
 /// Gets an already existing AbbrevTable given the abbrev_offset, or if not found,
 /// seeks in the stream and parses it.
-fn getAbbrevTable(st: &ElfStackTrace, abbrev_offset: u64) -> %&AbbrevTable {
-    for (st.abbrev_table_list.toSlice()) |header| {
+fn getAbbrevTable(st: &ElfStackTrace, abbrev_offset: u64) -> %&const AbbrevTable {
+    for (st.abbrev_table_list.toSlice()) |*header| {
         if (header.offset == abbrev_offset) {
             return &header.table;
         }
diff --git a/test/run_tests.cpp b/test/run_tests.cpp
index 7ecc1ca36c..bd551d9294 100644
--- a/test/run_tests.cpp
+++ b/test/run_tests.cpp
@@ -1595,6 +1595,16 @@ const zero: i32 = 0;
 const a = zero{1};
     )SOURCE", 1, ".tmp_source.zig:3:11: error: expected type, found 'i32'");
 
+    add_compile_fail_case("assign to constant field", R"SOURCE(
+const Foo = struct {
+    field: i32,
+};
+fn derp() {
+    const f = Foo {.field = 1234,};
+    f.field = 0;
+}
+    )SOURCE", 1, ".tmp_source.zig:7:13: error: cannot assign to constant");
+
 }
 
 //////////////////////////////////////////////////////////////////////////////
diff --git a/test/self_hosted.zig b/test/self_hosted.zig
index 4c791313db..a636f87cc7 100644
--- a/test/self_hosted.zig
+++ b/test/self_hosted.zig
@@ -2,7 +2,7 @@
 const test_array = @import("cases/array.zig");
 const test_atomics = @import("cases/atomics.zig");
 const test_bool = @import("cases/bool.zig");
-const test_cast= @import("cases/cast.zig");
+const test_cast = @import("cases/cast.zig");
 const test_const_slice_child = @import("cases/const_slice_child.zig");
 const test_defer = @import("cases/defer.zig");
 const test_enum = @import("cases/enum.zig");