Fix assert, address feedback, add tests

Author: cor3ntin

clang/include/clang/Sema/SemaConcept.h

@@ -196,7 +196,7 @@ struct NormalizedConstraint {
     assert(getKind() != ConstraintKind::Compound);
     assert(Indexes.count() == Args.size());
     assert(IndexesForSubsumption.size() == Indexes.size());
-    assert((Indexes & IndexesForSubsumption) == Indexes);
+    assert((Indexes | IndexesForSubsumption) == Indexes);
 
     Atomic.IndexesForSubsumption = std::move(IndexesForSubsumption);
     Atomic.Indexes = std::move(Indexes);

clang/lib/Sema/SemaTemplateDeduction.cpp

@@ -7182,7 +7182,6 @@ void Sema::MarkUsedTemplateParametersForSubsumptionParameterMapping(
     const Expr *E, unsigned Depth, llvm::SmallBitVector &Used) {
   MarkUsedTemplateParameterVisitor(Used, Depth, /*VisitDeclRefTypes=*/false)
       .TraverseStmt(const_cast<Expr *>(E));
-  return;
 }
 
 void

clang/test/SemaTemplate/instantiate-template-argument.cpp

@@ -27,3 +27,62 @@ static_assert(foo<'a'>() == 3);
 // expected-error@-1{{call to 'foo' is ambiguous}}
 // expected-note@#cand2 {{candidate function}}
 // expected-note@#cand3 {{candidate function}}
+
+
+namespace case1 {
+
+template<auto T, decltype(T) U>
+concept C1 = sizeof(T) >= 4; // #case1_C1
+
+template<typename Y, char V>
+concept C2 = C1<Y{}, V>; // #case1_C2
+
+template<class T, char W>
+constexpr int foo() requires C2<T, W> { return 1; } // #case1_foo1
+
+template<class T, char X>
+constexpr int foo() requires C1<T{}, X> && true { return 2; } // #case1_foo2
+
+static_assert(foo<char, 'a'>() == 2);
+// expected-error@-1{{no matching function for call to 'foo'}}
+// expected-note@#case1_foo1{{candidate template ignored: constraints not satisfied [with T = char, W = 'a']}}
+// expected-note@#case1_foo1{{because 'C2<char, 'a'>' evaluated to false}}
+// expected-note@#case1_C2{{because 'C1<Y{}, V>' evaluated to false}}
+// expected-note@#case1_C1{{because 'sizeof ('\x00') >= 4' (1 >= 4) evaluated to false}}
+// expected-note@#case1_foo2{{candidate template ignored: constraints not satisfied [with T = char, X = 'a']}}
+// expected-note@#case1_foo2{{because 'C1<char{}, 'a'>' evaluated to false}}
+// expected-note@#case1_C1{{because 'sizeof ('\x00') >= 4' (1 >= 4) evaluated to false}}
+
+static_assert(foo<int, 'a'>() == 2);
+
+}
+
+namespace case2 {
+template<auto T> concept C1 = sizeof(decltype(T)) >= 0;
+template<typename Y> concept C2 = C1<Y{}>;
+
+template<char W>
+constexpr int foo() requires C2<int> { return 1; }
+
+template<char X>
+constexpr int foo() requires C1<0> && true { return 2; }
+
+static_assert(foo<0>() == 2);
+}
+
+namespace case3 {
+template<auto T> concept C1 = sizeof(decltype(T)) >= 0;
+
+template<typename Y> concept C2 = C1<Y{}>;
+
+template<char W>
+constexpr int foo() requires C2<int> { return 1; } // #case3_foo1
+
+template<char X>
+constexpr int foo() requires C1<1> && true { return 2; } // #case3_foo2
+
+static_assert(foo<0>() == 2);
+// expected-error@-1{{call to 'foo' is ambiguous}}
+// expected-note@#case3_foo1 {{candidate function}}
+// expected-note@#case3_foo2 {{candidate function}}
+}