Skip to content

Allow OpImplicitCast in opOpAssign #110

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
zero-vector wants to merge 5 commits into
base: master
Choose a base branch
from
+83 −0
Open

Allow OpImplicitCast in opOpAssign #110

Changes from all commits
Commits
Show all changes
5 commits
Select commit Hold shift + click to select a range
9dfd4cb
`opOpAssign` now tries to match on `opImplicitCast`
zero-vector Dec 11, 2025
193766b
- Reworked to error out if more than one match is found.
zero-vector Dec 11, 2025
a4a4063
Fixed comment
zero-vector Dec 11, 2025
08291f2
Changed the way probing of `opImplicitCast` is done.
zero-vector Dec 13, 2025
f9adbfb
...
zero-vector Dec 13, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
83 changes: 83 additions & 0 deletions compiler/src/dmd/opover.d
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1257,6 +1257,10 @@ Expression op_overload(Expression e, Scope* sc, EXP* pop = null)

if (s)
{
enum MAX_RETRY_COUNT = 3;
int retryCount = 0;
RETRY_MATCH:

/* Try:
* a.opOpAssign(b)
*/
Expand All @@ -1276,6 +1280,85 @@ Expression op_overload(Expression e, Scope* sc, EXP* pop = null)
}
else if (m.last == MATCH.nomatch)
{
// NOTE(mojo): Try opImplicitCast
if (++retryCount < MAX_RETRY_COUNT) {
if (auto ad2 = isAggregate(e.e2.type)) {
if (auto implicitCastFd = search_function(ad2, Id._cast_impl)) {

// IMPORTANT: How to approach this v2:
// If s.isTemplateDeclaration we should probe all overloads
// We can not just probe parameter type as it can be some template param (`opOpAssign(string op: "~")(T rhs)`)
// Instead we check all `implicitCastTo` of e2.type.
// Cast OPs are done like this `(T : int)` so we shoult be able to try match on
// the `TemplateTypeParameter`, If we find exactly one match we costruct this `opImplicitCast`
// and re-run the matching.
// TODO: we check first parameter for TemplateTypeParameter, should be good enough for `implicitCastTo`
// but better make more robust checks in th future.

if (auto tdIc = implicitCastFd.isTemplateDeclaration()) {

int implicitCastMeatchCount = 0;
Expression matched_ex = null;

for (; tdIc; tdIc = tdIc.overnext)
{
if (!tdIc.parameters) continue;
auto tp = (*tdIc.parameters)[0];

if (auto ttp = tp.isTemplateTypeParameter()) {
auto implicitCastType = ttp.specType;

// printf("Probing: %s\n", implicitCastType.toChars());

// We try functionResolve on e1.opOpAssign(implicitCastType)
auto args3 = new Expressions();
args3.setDim(1);
(*args3)[0] = new TypeExp(e.loc, implicitCastType);
expandTuples(args3);

MatchAccumulator implicitOpMatch;
functionResolve(implicitOpMatch, s, e.loc, sc, tiargs, e.e1.type, ArgumentList(args3));

if (implicitOpMatch.count == 1) {
// If exactly one match, we rewrite e2 as e2.opImplicitCast!implicitCastType
auto tiargs2 = new Objects();
tiargs2.push(implicitCastType);
auto dti = new DotTemplateInstanceExp(e.e2.loc, e.e2, implicitCastFd.ident, tiargs2);
auto ce = new CallExp(e.e2.loc, dti);

// in theory we dont need`trySemantic`, as we contruct the call from implicitCastType
if (sc && .trySemantic(ce, sc)) {
matched_ex = ce.expressionSemantic(sc);
implicitCastMeatchCount += 1;

// Here it would be nice to exit early,
// but we still have to check if other `opImplicitCast1` dfoes not match.

// We dont need to do this beyond 2. cleatly ambiguity error
if (implicitCastMeatchCount > 1) break;
}
}
else if (implicitOpMatch.count > 1) {
// NOTE: isk how this could be more than 1, but I frer to asser.
error(e.loc, "ambiguous `opImplicitCast` in `%s` while trying to append to `%s`", ad2.toChars(), e.e1.type.toChars());
return ErrorExp.get();
}
}
}

if (implicitCastMeatchCount == 1) {
e.e2 = matched_ex;
goto RETRY_MATCH;
}
else if (implicitCastMeatchCount > 1) {
error(e.loc, "ambiguous `opImplicitCast` in `%s` while trying to append to `%s`", ad2.toChars(), e.e1.type.toChars());
return ErrorExp.get();
}
}
}
}
}

if (tiargs)
goto L1;
m.lastf = null;
Expand Down