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fix(0129): logical not is truthiness-aware, not a bit flip

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The unary .not arm emitted bool_not (LLVM bitwise Not) for every
operand. Correct on i1; on an error binding — an error-set value, u32
tag at the LLVM level — a bitwise not of a nonzero tag stays nonzero,
so 'if !e' held even on a SET error and its branch read the
uninitialized success value (real segfault in the distribution repo's
sqlite tests). Plain integers had the same hole ('!7' was '~7').

Now: bool keeps bool_not; integers and error-set operands lower as the
truthiness complement (cmp_eq against a typed zero); anything else is
diagnosed instead of silently bit-flipped.

Regression: examples/1057 (set error: !e must not hold; success: !e
holds with a real value; integer truthiness) + examples/1171 (!"text"
diagnosed); both FAIL pre-fix. zig build test 426/426;
tests/run_examples.sh 600/600.
This commit is contained in:
agra
2026-06-12 13:36:54 +03:00
parent ba37d0b393
commit a8fbded567
10 changed files with 148 additions and 1 deletions
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23
src/ir/lower/expr.zig
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@@ -2030,7 +2030,28 @@ pub fn lowerExpr(self: *Lowering, node: *const Node) Ref {
self.suppress_int_fit_check = saved_fit;
break :blk switch (uop.op) {
.negate => self.builder.emit(.{ .neg = .{ .operand = operand } }, self.inferExprType(uop.operand)),
.not => self.builder.emit(.{ .bool_not = .{ .operand = operand } }, .bool),
// `!` is LOGICAL not. Only a real bool may go through the
// bitwise `bool_not` (i1); an integer-backed operand — an
// error binding (u32 tag), a plain integer — lowers as the
// truthiness complement `operand == 0`: a bitwise not of a
// nonzero tag stays nonzero, so `if !e` held even on a set
// error (issue 0129). Anything else is diagnosed.
.not => blk2: {
const oty = self.inferExprType(uop.operand);
if (oty == .bool) {
break :blk2 self.builder.emit(.{ .bool_not = .{ .operand = operand } }, .bool);
}
const int_like = self.isIntEx(oty) or
(!oty.isBuiltin() and self.module.types.get(oty) == .error_set);
if (int_like) {
const zero = self.builder.constInt(0, oty);
break :blk2 self.builder.emit(.{ .cmp_eq = .{ .lhs = operand, .rhs = zero } }, .bool);
}
if (self.diagnostics) |d| {
d.addFmt(.err, node.span, "'!' needs a bool, integer, or error operand; got '{s}'", .{self.formatTypeName(oty)});
}
break :blk2 self.builder.constBool(false);
},
.bit_not => self.builder.emit(.{ .bit_not = .{ .operand = operand } }, self.inferExprType(uop.operand)),
.xx => self.lowerXX(operand, uop.operand),
.address_of => blk2: {