[clang] b9a77b5 - [Concepts] Fix an assert when trying to form a recovery expr on a
Erich Keane via cfe-commits
cfe-commits at lists.llvm.org
Fri Oct 28 10:25:40 PDT 2022
Author: Erich Keane
Date: 2022-10-28T10:25:34-07:00
New Revision: b9a77b56d83ac788beb7b1743e510ef8534354ca
URL: https://github.com/llvm/llvm-project/commit/b9a77b56d83ac788beb7b1743e510ef8534354ca
DIFF: https://github.com/llvm/llvm-project/commit/b9a77b56d83ac788beb7b1743e510ef8534354ca.diff
LOG: [Concepts] Fix an assert when trying to form a recovery expr on a
concept
When we failed the lookup of the function, we tried to form a
RecoveryExpr that caused us to recursively re-check the same constraint,
which caused us to try to double-insert the satisfaction into the cache.
This patch makes us just return the inner-cached version instead. We DO
end up double-evaluating thanks to the recovery-expr, but there isn't a
good way around that.
Added:
clang/test/SemaTemplate/concepts-GH53213.cpp
Modified:
clang/docs/ReleaseNotes.rst
clang/lib/Sema/SemaConcept.cpp
Removed:
################################################################################
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 3896c6120612e..7f02e843f39dc 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -260,6 +260,10 @@ Bug Fixes
- Fix template arguments of pointer and reference not taking the type as
part of their identity.
`Issue 47136 <https://github.com/llvm/llvm-project/issues/47136>`_
+- Fix a crash when trying to form a recovery expression on a call inside a
+ constraint, which re-evaluated the same constraint.
+ `Issue 53213 <https://github.com/llvm/llvm-project/issues/53213>`_
+ `Issue 45736 <https://github.com/llvm/llvm-project/issues/45736>`_
Improvements to Clang's diagnostics
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/Sema/SemaConcept.cpp b/clang/lib/Sema/SemaConcept.cpp
index 9a919116a3c64..d3d87c8354aea 100644
--- a/clang/lib/Sema/SemaConcept.cpp
+++ b/clang/lib/Sema/SemaConcept.cpp
@@ -408,6 +408,7 @@ bool Sema::CheckConstraintSatisfaction(
OutSatisfaction = *Cached;
return false;
}
+
auto Satisfaction =
std::make_unique<ConstraintSatisfaction>(Template, FlattenedArgs);
if (::CheckConstraintSatisfaction(*this, Template, ConstraintExprs,
@@ -415,6 +416,21 @@ bool Sema::CheckConstraintSatisfaction(
TemplateIDRange, *Satisfaction)) {
return true;
}
+
+ if (auto *Cached = SatisfactionCache.FindNodeOrInsertPos(ID, InsertPos)) {
+ // The evaluation of this constraint resulted in us trying to re-evaluate it
+ // recursively. This isn't really possible, except we try to form a
+ // RecoveryExpr as a part of the evaluation. If this is the case, just
+ // return the 'cached' version (which will have the same result), and save
+ // ourselves the extra-insert. If it ever becomes possible to legitimately
+ // recursively check a constraint, we should skip checking the 'inner' one
+ // above, and replace the cached version with this one, as it would be more
+ // specific.
+ OutSatisfaction = *Cached;
+ return false;
+ }
+
+ // Else we can simply add this satisfaction to the list.
OutSatisfaction = *Satisfaction;
// We cannot use InsertPos here because CheckConstraintSatisfaction might have
// invalidated it.
diff --git a/clang/test/SemaTemplate/concepts-GH53213.cpp b/clang/test/SemaTemplate/concepts-GH53213.cpp
new file mode 100644
index 0000000000000..23bd70b013027
--- /dev/null
+++ b/clang/test/SemaTemplate/concepts-GH53213.cpp
@@ -0,0 +1,49 @@
+// RUN: %clang_cc1 -std=c++20 -verify %s
+namespace GH53213 {
+template<typename T>
+concept c = requires(T t) { f(t); }; // #CDEF
+
+auto f(c auto); // #FDEF
+
+void g() {
+ f(0);
+ // expected-error at -1{{no matching function for call to 'f'}}
+ // expected-note@#FDEF{{constraints not satisfied}}
+ // expected-note@#FDEF{{because 'int' does not satisfy 'c'}}
+ // expected-note@#CDEF{{because 'f(t)' would be invalid: no matching function for call to 'f'}}
+}
+} // namespace GH53213
+
+namespace GH45736 {
+struct constrained;
+
+template<typename T>
+ struct type {
+ };
+template<typename T>
+ constexpr bool f(type<T>) {
+ return true;
+ }
+
+template<typename T>
+ concept matches = f(type<T>());
+
+
+struct constrained {
+ template<typename U> requires matches<U>
+ explicit constrained(U value) {
+ }
+};
+
+bool f(constrained const &) {
+ return true;
+}
+
+struct outer {
+ constrained state;
+};
+
+bool f(outer const & x) {
+ return f(x.state);
+}
+} // namespace GH45736
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