diff --git a/src/codegen.cpp b/src/codegen.cpp
index c533e66d61..e3f182e17c 100644
--- a/src/codegen.cpp
+++ b/src/codegen.cpp
@@ -1790,7 +1790,8 @@ static LLVMValueRef ir_render_bin_op(CodeGen *g, IrExecutable *executable,
 
     assert(op1->value.type == op2->value.type || op_id == IrBinOpBitShiftLeftLossy ||
             op_id == IrBinOpBitShiftLeftExact || op_id == IrBinOpBitShiftRightLossy ||
-            op_id == IrBinOpBitShiftRightExact);
+            op_id == IrBinOpBitShiftRightExact ||
+            (op1->value.type->id == TypeTableEntryIdErrorSet && op2->value.type->id == TypeTableEntryIdErrorSet));
     TypeTableEntry *type_entry = op1->value.type;
 
     bool want_runtime_safety = bin_op_instruction->safety_check_on &&
diff --git a/src/ir.cpp b/src/ir.cpp
index 3f3dfb1ad7..0f9020c9dc 100644
--- a/src/ir.cpp
+++ b/src/ir.cpp
@@ -7258,8 +7258,8 @@ static TypeTableEntry *ir_resolve_peer_types(IrAnalyze *ira, AstNode *source_nod
                     continue;
                 }
                 // unset all the errors
-                for (uint32_t i = 0; i < prev_err_set_type->data.error_set.err_count; i += 1) {
-                    ErrorTableEntry *error_entry = prev_err_set_type->data.error_set.errors[i];
+                for (uint32_t i = 0; i < err_set_type->data.error_set.err_count; i += 1) {
+                    ErrorTableEntry *error_entry = err_set_type->data.error_set.errors[i];
                     errors[error_entry->value] = nullptr;
                 }
                 for (uint32_t i = 0; i < cur_err_set_type->data.error_set.err_count; i += 1) {
@@ -7320,6 +7320,19 @@ static TypeTableEntry *ir_resolve_peer_types(IrAnalyze *ira, AstNode *source_nod
         if (cur_type->id == TypeTableEntryIdErrorUnion &&
                 types_match_const_cast_only(ira, cur_type->data.error_union.payload_type, prev_type, source_node).id == ConstCastResultIdOk)
         {
+            if (err_set_type != nullptr) {
+                TypeTableEntry *cur_err_set_type = cur_type->data.error_union.err_set_type;
+                if (!resolve_inferred_error_set(ira, cur_err_set_type, cur_inst->source_node)) {
+                    return ira->codegen->builtin_types.entry_invalid;
+                }
+                if (type_is_global_error_set(cur_err_set_type) || type_is_global_error_set(err_set_type)) {
+                    err_set_type = ira->codegen->builtin_types.entry_global_error_set;
+                    prev_inst = cur_inst;
+                    continue;
+                }
+
+                err_set_type = get_error_set_union(ira->codegen, errors, err_set_type, cur_err_set_type);
+            }
             prev_inst = cur_inst;
             continue;
         }
diff --git a/std/debug/index.zig b/std/debug/index.zig
index a759a2af16..2bb03a6706 100644
--- a/std/debug/index.zig
+++ b/std/debug/index.zig
@@ -264,7 +264,7 @@ pub fn openSelfDebugInfo(allocator: &mem.Allocator) !&ElfStackTrace {
     }
 }
 
-fn printLineFromFile(allocator: &mem.Allocator, out_stream: &io.OutStream, line_info: &const LineInfo) !void {
+fn printLineFromFile(allocator: &mem.Allocator, out_stream: var, line_info: &const LineInfo) !void {
     var f = try io.File.openRead(line_info.file_name, allocator);
     defer f.close();
     // TODO fstat and make sure that the file has the correct size
@@ -1054,7 +1054,7 @@ fn readULeb128(in_stream: var) !u64 {
     }
 }
 
-fn readILeb128(in_stream: &io.InStream) !i64 {
+fn readILeb128(in_stream: var) !i64 {
     var result: i64 = 0;
     var shift: usize = 0;