mirror/zig
1
0
Fork 0
mirror of https://github.com/ziglang/zig.git synced 2026-01-20 14:25:16 +00:00
Code Issues Packages Projects Releases Wiki Activity

AstGen: make pointless discard error more strict

Browse Source 
The error should only happen as a result of `_ = <expr>` not
for an operand of a break expression that is discarded.

Closes #13212
This commit is contained in:
Veikka Tuominen 2022-11-08 19:48:21 +02:00
parent d2cc55109a
commit 0a188190b3
2 changed files with 20 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
src/AstGen.zig
View File

@ -339,6 +339,8 @@ pub const ResultInfo = struct {
fn_arg,
/// The expression is the right-hand side of an initializer for a `const` variable
const_init,
/// The expression is the right-hand side of an assignment expression.
assignment,
/// No specific operator in particular.
none,
};
@ -3216,7 +3218,7 @@ fn assign(gz: *GenZir, scope: *Scope, infix_node: Ast.Node.Index) InnerError!voi
// This intentionally does not support `@"_"` syntax.
const ident_name = tree.tokenSlice(main_tokens[lhs]);
if (mem.eql(u8, ident_name, "_")) {
_ = try expr(gz, scope, .{ .rl = .discard }, rhs);
_ = try expr(gz, scope, .{ .rl = .discard, .ctx = .assignment }, rhs);
return;
}
}
@ -7088,7 +7090,7 @@ fn localVarRef(
if (local_val.name == name_str_index) {
// Locals cannot shadow anything, so we do not need to look for ambiguous
// references in this case.
if (ri.rl == .discard) {
if (ri.rl == .discard and ri.ctx == .assignment) {
local_val.discarded = ident_token;
} else {
local_val.used = ident_token;
@ -7111,7 +7113,7 @@ fn localVarRef(
.local_ptr => {
const local_ptr = s.cast(Scope.LocalPtr).?;
if (local_ptr.name == name_str_index) {
if (ri.rl == .discard) {
if (ri.rl == .discard and ri.ctx == .assignment) {
local_ptr.discarded = ident_token;
} else {
local_ptr.used = ident_token;
@ -10672,14 +10674,19 @@ const GenZir = struct {
gz.break_result_info = parent_ri;
},
.discard, .none, .ref => {
.none, .ref => {
gz.rl_ty_inst = .none;
gz.break_result_info = parent_ri;
},
.discard => {
gz.rl_ty_inst = .none;
gz.break_result_info = .{ .rl = .discard };
},
.ptr => |ptr_res| {
gz.rl_ty_inst = .none;
gz.break_result_info = .{ .rl = .{ .ptr = .{ .inst = ptr_res.inst } } };
gz.break_result_info = .{ .rl = .{ .ptr = .{ .inst = ptr_res.inst } }, .ctx = parent_ri.ctx };
},
.inferred_ptr => |ptr| {

8
test/cases/compile_errors/pointless discard.zig
View File

@ -3,6 +3,14 @@ export fn foo() void {
x += 1;
_ = x;
}
export fn bar() void {
var b: u32 = 1;
_ = blk: {
const a = 1;
b = a;
break :blk a;
};
}
// error
// backend=stage2