commit 044ba3e0b020c317e8934d0d8271a512a9deeff8 (tree)
parent 4fcf6507f9f96d1f341819dab89ded74cd3c7f7d
Author: Justus Klausecker <justus@klausecker.de>
Date: Mon, 12 Jan 2026 19:59:47 +0100
Sema: fix single-range switch prong capture (for real this time)
e2338edb47 didn't *quite* do it, the call sites of all switch prong related
functions now have to do their part too and be a little more precise about
what kind of prong they're currently analyzing.
Also removes some unused/unnecessary stuff.
Diffstat:
3 files changed, 70 insertions(+), 74 deletions(-)
diff --git a/lib/std/zig/Zir.zig b/lib/std/zig/Zir.zig
@@ -3438,8 +3438,6 @@ pub const Inst = struct {
return if (item_info.kind == .body_len) item_info.data else null;
}
};
-
- pub const Kind = enum { default, ref, err_union };
};
pub const ArrayInitRefTy = struct {
diff --git a/src/Sema.zig b/src/Sema.zig
@@ -10747,8 +10747,6 @@ fn analyzeSwitchBlock(
const operand_src = block.src(.{ .node_offset_switch_operand = src_node_offset });
const has_else = zir_switch.else_case != null;
- const has_under = zir_switch.has_under;
-
const else_case = validated_switch.else_case;
const operand: SwitchOperand, const operand_ty: Type, const maybe_operand_opv: ?Value, const item_ty: Type = operand: {
@@ -10813,11 +10811,6 @@ fn analyzeSwitchBlock(
.loop => |l| l.init_cond,
};
- // We treat `else` and `_` the same, except if both are present.
- const else_is_named_only = has_else and has_under;
- const catch_all_case: CatchAllSwitchCase =
- if (has_under) .under else if (has_else) .@"else" else .none;
-
resolve_at_comptime: {
// always runtime; evaluation in comptime scope uses `simple`
if (operand == .loop) break :resolve_at_comptime;
@@ -10834,8 +10827,6 @@ fn analyzeSwitchBlock(
cur_operand,
raw_operand_ty,
cur_cond_val,
- catch_all_case,
- else_is_named_only,
merges,
switch_inst,
zir_switch,
@@ -10958,6 +10949,11 @@ fn analyzeSwitchBlock(
}
},
};
+ const prong_kind: SwitchProngKind = kind: {
+ if (is_inline) break :kind .{ .inline_ref = .fromValue(item_opv) };
+ if (is_special) break :kind .special;
+ break :kind .{ .item_refs = &.{.fromValue(item_opv)} };
+ };
break :payload_ref try sema.analyzeSwitchPayloadCapture(
&case_block,
operand,
@@ -10970,8 +10966,7 @@ fn analyzeSwitchBlock(
.case_idx = index,
} }),
capture == .by_ref,
- if (is_special) .special else .{ .item_refs = &.{.fromValue(item_opv)} },
- if (is_inline) .fromValue(item_opv) else .none,
+ prong_kind,
validated_switch.else_err_ty,
);
},
@@ -11094,8 +11089,6 @@ fn finishSwitchBr(
const cond_dbg_node_index: Zir.Inst.Index = @enumFromInt(@intFromEnum(switch_inst) - 1);
const else_is_named_only = has_else and has_under;
- const catch_all_case: CatchAllSwitchCase =
- if (has_under) .under else if (has_else) .@"else" else .none;
const item_ty = switch (operand_ty.zigTypeTag(zcu)) {
.@"union" => operand_ty.unionTagType(zcu).?,
@@ -11216,8 +11209,7 @@ fn finishSwitchBr(
} }),
prong_info.capture,
prong_info.has_tag_capture,
- item_ref,
- .{ .item_refs = &.{item_ref} },
+ .{ .inline_ref = item_ref },
validated_switch.else_err_ty,
switch_inst,
zir_switch,
@@ -11308,8 +11300,7 @@ fn finishSwitchBr(
} }),
prong_info.capture,
prong_info.has_tag_capture,
- item_ref,
- .has_ranges,
+ .{ .inline_ref = item_ref },
validated_switch.else_err_ty,
switch_inst,
zir_switch,
@@ -11333,6 +11324,9 @@ fn finishSwitchBr(
if (prong_info.is_inline) continue; // handled above
if (is_under_prong) {
+ // We will handle this later. If there are any named items specified
+ // along with the `_`, we don't have to actually emit any AIR for them
+ // as they will be 'absorbed' by the `_` (the catch-all prong) anyway.
under_prong = .{
.index = case.index,
.body = prong_body,
@@ -11359,8 +11353,7 @@ fn finishSwitchBr(
} }),
prong_info.capture,
prong_info.has_tag_capture,
- .none,
- .{ .item_refs = item_refs },
+ if (range_refs.len > 0) .has_ranges else .{ .item_refs = item_refs },
validated_switch.else_err_ty,
switch_inst,
zir_switch,
@@ -11385,7 +11378,7 @@ fn finishSwitchBr(
}
const catch_all_extra: []const u32 = catch_all_extra: {
- if (catch_all_case == .none and !case_block.wantSafety()) {
+ if (!has_else and !has_under and !case_block.wantSafety()) {
try branch_hints.append(gpa, .none);
break :catch_all_extra &.{};
}
@@ -11445,8 +11438,7 @@ fn finishSwitchBr(
} }),
else_case.capture,
else_case.has_tag_capture,
- item_ref,
- .special,
+ .{ .inline_ref = item_ref },
validated_switch.else_err_ty,
switch_inst,
zir_switch,
@@ -11473,7 +11465,7 @@ fn finishSwitchBr(
case_block.error_return_trace_index = child_block.error_return_trace_index;
if (zcu.backendSupportsFeature(.is_named_enum_value) and
- catch_all_case != .none and block.wantSafety() and
+ (has_else or has_under) and block.wantSafety() and
item_ty.zigTypeTag(zcu) == .@"enum" and
(!operand_ty.isNonexhaustiveEnum(zcu) or union_originally))
{
@@ -11508,7 +11500,6 @@ fn finishSwitchBr(
} }),
else_case.capture,
else_case.has_tag_capture,
- .none,
.special,
validated_switch.else_err_ty,
switch_inst,
@@ -11548,10 +11539,12 @@ fn finishSwitchBr(
}
const analyze_catch_all_body = analyze_body: {
- switch (catch_all_case) {
- .none => break :analyze_body false, // we still may want a safety check!
- .under => break :analyze_body true, // can't be a union anyway
- .@"else" => if (else_case.is_inline) break :analyze_body false,
+ if (has_under) {
+ break :analyze_body true; // can't be a union or an error set, never inlined
+ } else if (has_else) {
+ if (else_case.is_inline) break :analyze_body false; // already handled above
+ } else {
+ break :analyze_body false; // we still may want a safety check!
}
if (union_originally) {
const union_obj = zcu.typeToUnion(operand_ty).?;
@@ -11574,11 +11567,10 @@ fn finishSwitchBr(
const catch_all_hint = hint: {
if (analyze_catch_all_body) {
- const index, const body, const capture, const has_tag_capture = switch (catch_all_case) {
- .@"else" => .{ else_case.index, else_case.body, else_case.capture, else_case.has_tag_capture },
- .under => .{ under_prong.?.index, under_prong.?.body, under_prong.?.capture, under_prong.?.has_tag_capture },
- .none => unreachable,
- };
+ const index, const body, const capture, const has_tag_capture = if (under_prong) |under|
+ .{ under.index, under.body, under.capture, under.has_tag_capture }
+ else
+ .{ else_case.index, else_case.body, else_case.capture, else_case.has_tag_capture };
break :hint try sema.analyzeSwitchProng(
&case_block,
operand,
@@ -11591,7 +11583,6 @@ fn finishSwitchBr(
} }),
capture,
has_tag_capture,
- .none,
.special,
validated_switch.else_err_ty,
switch_inst,
@@ -12072,9 +12063,9 @@ fn validateSwitchBlock(
const msg = try sema.errMsg(
operand_src,
"ranges not allowed when switching on type '{f}'",
- .{operand_ty.fmt(sema.pt)},
+ .{operand_ty.fmt(pt)},
);
- errdefer msg.destroy(sema.gpa);
+ errdefer msg.destroy(gpa);
try sema.errNote(
range_src,
msg,
@@ -12309,8 +12300,6 @@ fn resolveSwitchBlock(
operand: SwitchOperand,
raw_operand_ty: Type,
maybe_lazy_cond_val: Value,
- catch_all_case: CatchAllSwitchCase,
- else_is_named_only: bool,
merges: *Block.Merges,
switch_inst: Zir.Inst.Index,
zir_switch: *const Zir.UnwrappedSwitchBlock,
@@ -12377,6 +12366,11 @@ fn resolveSwitchBlock(
// This prong should be unreachable!
return .unreachable_value;
}
+ const prong_kind: SwitchProngKind = kind: {
+ if (prong_info.is_inline) break :kind .{ .inline_ref = cond_ref };
+ if (range_refs.len > 0) break :kind .has_ranges;
+ break :kind .{ .item_refs = item_refs };
+ };
return sema.resolveSwitchProng(
block,
child_block,
@@ -12389,8 +12383,7 @@ fn resolveSwitchBlock(
} }),
prong_info.capture,
prong_info.has_tag_capture,
- if (prong_info.is_inline) cond_ref else .none,
- .{ .item_refs = item_refs },
+ prong_kind,
validated_switch.else_err_ty,
merges,
switch_inst,
@@ -12404,6 +12397,10 @@ fn resolveSwitchBlock(
if ((try sema.compareAll(cond_val, .gte, first_val, item_ty)) and
(try sema.compareAll(cond_val, .lte, last_val, item_ty)))
{
+ const prong_kind: SwitchProngKind = if (prong_info.is_inline)
+ .{ .inline_ref = cond_ref }
+ else
+ .has_ranges;
return sema.resolveSwitchProng(
block,
child_block,
@@ -12416,8 +12413,7 @@ fn resolveSwitchBlock(
} }),
prong_info.capture,
prong_info.has_tag_capture,
- if (prong_info.is_inline) cond_ref else .none,
- .has_ranges,
+ prong_kind,
validated_switch.else_err_ty,
merges,
switch_inst,
@@ -12428,11 +12424,16 @@ fn resolveSwitchBlock(
}
const else_case = validated_switch.else_case;
+ const else_is_named_only = zir_switch.else_case != null and under_prong != null;
// named-only prong
if (else_is_named_only and item_ty.enumTagFieldIndex(cond_val, zcu) != null) {
assert(item_ty.isNonexhaustiveEnum(zcu));
+ const prong_kind: SwitchProngKind = if (else_case.is_inline)
+ .{ .inline_ref = cond_ref }
+ else
+ .special;
return sema.resolveSwitchProng(
block,
child_block,
@@ -12445,8 +12446,7 @@ fn resolveSwitchBlock(
} }),
else_case.capture,
else_case.has_tag_capture,
- if (else_case.is_inline) cond_ref else .none,
- .special,
+ prong_kind,
validated_switch.else_err_ty,
merges,
switch_inst,
@@ -12456,11 +12456,10 @@ fn resolveSwitchBlock(
// catch-all prong
- const index, const body, const capture, const has_tag_capture, const is_inline = switch (catch_all_case) {
- .@"else" => .{ else_case.index, else_case.body, else_case.capture, else_case.has_tag_capture, else_case.is_inline },
- .under => .{ under_prong.?.index, under_prong.?.body, under_prong.?.capture, under_prong.?.has_tag_capture, false },
- .none => unreachable,
- };
+ const index, const body, const capture, const has_tag_capture, const is_inline = if (under_prong) |under|
+ .{ under.index, under.body, under.capture, under.has_tag_capture, false }
+ else
+ .{ else_case.index, else_case.body, else_case.capture, else_case.has_tag_capture, else_case.is_inline };
if (err_set) try sema.maybeErrorUnwrapComptime(child_block, body, cond_ref);
if (union_originally) {
for (validated_switch.seen_enum_fields, 0..) |maybe_seen, field_i| {
@@ -12471,6 +12470,10 @@ fn resolveSwitchBlock(
return .unreachable_value;
}
}
+ const prong_kind: SwitchProngKind = if (is_inline)
+ .{ .inline_ref = cond_ref }
+ else
+ .special;
return sema.resolveSwitchProng(
block,
child_block,
@@ -12483,8 +12486,7 @@ fn resolveSwitchBlock(
} }),
capture,
has_tag_capture,
- if (is_inline) cond_ref else .none,
- .special,
+ prong_kind,
validated_switch.else_err_ty,
merges,
switch_inst,
@@ -12520,9 +12522,9 @@ const SwitchOperand = union(enum) {
},
};
-const CatchAllSwitchCase = enum { none, @"else", under };
-
const SwitchProngKind = union(enum) {
+ /// Prefer populating this field over the others, if possible.
+ inline_ref: Air.Inst.Ref,
item_refs: []const Air.Inst.Ref,
has_ranges,
special,
@@ -12541,7 +12543,6 @@ fn resolveSwitchProng(
capture_src: LazySrcLoc,
capture: Zir.Inst.SwitchBlock.ProngInfo.Capture,
has_tag_capture: bool,
- inline_case_capture: Air.Inst.Ref,
kind: SwitchProngKind,
else_err_ty: ?Type,
merges: *Block.Merges,
@@ -12569,7 +12570,6 @@ fn resolveSwitchProng(
capture_src,
capture == .by_ref,
kind,
- inline_case_capture,
else_err_ty,
);
assert(!sema.typeOf(payload_ref).isNoReturn(sema.pt.zcu));
@@ -12585,7 +12585,6 @@ fn resolveSwitchProng(
operand.simple.by_val,
sema.typeOf(operand.simple.by_val),
capture_src,
- inline_case_capture,
kind,
);
sema.inst_map.putAssumeCapacity(tag_inst, tag_ref);
@@ -12637,7 +12636,6 @@ fn analyzeSwitchProng(
capture_src: LazySrcLoc,
capture: Zir.Inst.SwitchBlock.ProngInfo.Capture,
has_tag_capture: bool,
- inline_case_capture: Air.Inst.Ref,
kind: SwitchProngKind,
else_err_ty: ?Type,
switch_inst: Zir.Inst.Index,
@@ -12664,7 +12662,7 @@ fn analyzeSwitchProng(
// No need to load the operand for this prong!
break :load_operand .{ undefined, undefined };
}
- if (inline_case_capture != .none and
+ if (kind == .inline_ref and
!(capture != .none and operand_ty.zigTypeTag(zcu) == .@"union"))
{
// We only need to load the operand if there's a union payload capture
@@ -12698,7 +12696,6 @@ fn analyzeSwitchProng(
capture_src,
capture == .by_ref,
kind,
- inline_case_capture,
else_err_ty,
);
assert(!sema.typeOf(payload_ref).isNoReturn(sema.pt.zcu));
@@ -12714,7 +12711,6 @@ fn analyzeSwitchProng(
operand_val,
operand_ty,
capture_src,
- inline_case_capture,
kind,
);
sema.inst_map.putAssumeCapacity(tag_inst, tag_ref);
@@ -12735,7 +12731,6 @@ fn analyzeSwitchTagCapture(
operand_val: Air.Inst.Ref,
operand_ty: Type,
capture_src: LazySrcLoc,
- inline_case_capture: Air.Inst.Ref,
kind: SwitchProngKind,
) CompileError!Air.Inst.Ref {
const pt = sema.pt;
@@ -12751,12 +12746,11 @@ fn analyzeSwitchTagCapture(
operand_ty.fmt(pt),
});
}
- if (inline_case_capture != .none) {
- return inline_case_capture; // this already is the tag, it's what we're switching on!
- }
switch (kind) {
- .has_ranges, .special => {},
+ .has_ranges => unreachable,
+ .inline_ref => |ref| return ref,
.item_refs => |refs| if (refs.len == 1) return refs[0],
+ .special => {},
}
const tag_ty = operand_ty.unionTagType(zcu).?;
return sema.unionToTag(case_block, tag_ty, operand_val, tag_capture_src);
@@ -12775,8 +12769,6 @@ fn analyzeSwitchPayloadCapture(
capture_src: LazySrcLoc,
capture_by_ref: bool,
kind: SwitchProngKind,
- /// If this is not `.none`, this is an inline capture.
- inline_case_capture: Air.Inst.Ref,
else_err_ty: ?Type,
) CompileError!Air.Inst.Ref {
const pt = sema.pt;
@@ -12785,8 +12777,8 @@ fn analyzeSwitchPayloadCapture(
const switch_node_offset = operand_src.offset.node_offset_switch_operand;
- if (inline_case_capture != .none) {
- const item_val = sema.resolveConstDefinedValue(case_block, .unneeded, inline_case_capture, undefined) catch unreachable;
+ if (kind == .inline_ref) {
+ const item_val = sema.resolveConstDefinedValue(case_block, .unneeded, kind.inline_ref, undefined) catch unreachable;
if (operand_ty.zigTypeTag(zcu) == .@"union") {
const field_index: u32 = @intCast(operand_ty.unionTagFieldIndex(item_val, zcu).?);
const union_obj = zcu.typeToUnion(operand_ty).?;
@@ -12812,7 +12804,7 @@ fn analyzeSwitchPayloadCapture(
} else if (capture_by_ref) {
return sema.uavRef(item_val.toIntern());
} else {
- return inline_case_capture;
+ return kind.inline_ref;
}
}
@@ -13155,7 +13147,7 @@ fn analyzeSwitchPayloadCapture(
return operand_ptr;
}
switch (kind) {
- .special => unreachable,
+ .inline_ref, .special => unreachable,
.item_refs => |case_vals| {
// If there's only a single item, the capture is comptime-known!
if (case_vals.len == 1) return case_vals[0];
diff --git a/test/behavior/switch.zig b/test/behavior/switch.zig
@@ -1308,7 +1308,7 @@ test "single-item prong in switch on enum has comptime-known capture" {
try comptime E.doTheTest(.a);
}
-test "single-range switch prong capture" {
+test "single range switch prong capture" {
const S = struct {
fn doTheTest(x: u8) !void {
switch (x) {
@@ -1317,6 +1317,12 @@ test "single-range switch prong capture" {
},
else => return error.TestFailed,
}
+ switch (x) {
+ 1...5, 6 => |val| {
+ try expect(val == 2);
+ },
+ else => return error.TestFailed,
+ }
}
};
try S.doTheTest(2);
