[PATCH] D121646: [Concepts] Fix an assertion failure while diagnosing constrained function candidates

[Roy Jacobson via Phabricator via cfe-commits]

royjacobson created this revision.
royjacobson added a reviewer: erichkeane.
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royjacobson requested review of this revision.
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See: https://github.com/llvm/llvm-project/issues/54379

I tried to see if I can reuse `ResolveAddressOfOverloadedFunction` for explicit function instantiation and so I managed to hit this ICE.

Bug was the diagnostic required an argument (%0) and specific code path didn't pass an argument.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D121646

Files:
  clang/lib/Sema/SemaOverload.cpp
  clang/test/SemaTemplate/concepts.cpp


Index: clang/test/SemaTemplate/concepts.cpp
===================================================================
--- clang/test/SemaTemplate/concepts.cpp
+++ clang/test/SemaTemplate/concepts.cpp
@@ -208,3 +208,17 @@
     return (int*)nullptr; // FIXME: should error
   }
 }
+
+namespace PR54379 {
+template <int N>
+struct A {
+  static void f() requires (N == 0) { return; } // expected-note {{candidate template ignored: constraints not satisfied}} expected-note {{evaluated to false}}
+  static void f() requires (N == 1) { return; } // expected-note {{candidate template ignored: constraints not satisfied}} expected-note {{evaluated to false}}
+};
+void (*f1)() = A<2>::f; // expected-error {{address of overloaded function 'f' does not match required type}}
+
+struct B {
+  template <int N2 = 1> static void f() requires (N2 == 0) { return; }  // expected-note {{candidate template ignored: constraints not satisfied [with N2 = 1]}} expected-note {{evaluated to false}}
+};
+void (*f2)() = B::f; // expected-error {{address of overloaded function 'f' does not match required type}}
+}
Index: clang/lib/Sema/SemaOverload.cpp
===================================================================
--- clang/lib/Sema/SemaOverload.cpp
+++ clang/lib/Sema/SemaOverload.cpp
@@ -10256,10 +10256,19 @@
       return false;
     if (!Satisfaction.IsSatisfied) {
       if (Complain) {
-        if (InOverloadResolution)
+        if (InOverloadResolution) {
+          SmallString<128> TemplateArgString;
+          TemplateArgString.clear();
+          if (FunctionTemplateDecl *FunTmpl = FD->getPrimaryTemplate()) {
+            TemplateArgString += " ";
+            TemplateArgString += S.getTemplateArgumentBindingsText(
+              FunTmpl->getTemplateParameters(), *FD->getTemplateSpecializationArgs());
+          }
+
           S.Diag(FD->getBeginLoc(),
-                 diag::note_ovl_candidate_unsatisfied_constraints);
-        else
+                 diag::note_ovl_candidate_unsatisfied_constraints)
+              << TemplateArgString;
+        } else
           S.Diag(Loc, diag::err_addrof_function_constraints_not_satisfied)
               << FD;
         S.DiagnoseUnsatisfiedConstraint(Satisfaction);


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