[clang] [clang] Improve source location in binary type traits diagnostics (PR #88097)

[Vlad Serebrennikov via cfe-commits]

https://github.com/Endilll created https://github.com/llvm/llvm-project/pull/88097

This patch takes advantage of a recent NFC change that refactored `EvaluateBinaryTypeTrait()` to accept `TypeSourceInfo` instead of `QualType` c7db450e5c1a83ea768765dcdedfd50f3358d418.
Before:
```
test2.cpp:105:55: error: variable length arrays are not supported in '__is_layout_compatible'
  105 |   static_assert(!__is_layout_compatible(int[n], int[n]));
      |                                                       ^
test2.cpp:125:76: error: incomplete type 'CStructIncomplete' where a complete type is required
  125 |   static_assert(__is_layout_compatible(CStructIncomplete, CStructIncomplete));
      |                                                                            ^
``` 
After:
```
test2.cpp:105:41: error: variable length arrays are not supported in '__is_layout_compatible'
  105 |   static_assert(!__is_layout_compatible(int[n], int[n]));
      |                                         ^
test2.cpp:125:40: error: incomplete type 'CStructIncomplete' where a complete type is required
  125 |   static_assert(__is_layout_compatible(CStructIncomplete, CStructIncomplete));
      |                                        ^
```

>From 3bc2d71cbe5e5613b430968fe84023a736072e54 Mon Sep 17 00:00:00 2001
From: Vlad Serebrennikov <serebrennikov.vladislav at gmail.com>
Date: Tue, 9 Apr 2024 10:20:10 +0300
Subject: [PATCH] [clang] Improve source location in binary type traits
 diagnostics

---
 clang/lib/Sema/SemaExprCXX.cpp     | 21 ++++++++++++---------
 clang/test/SemaCXX/type-traits.cpp |  1 +
 2 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp
index dee6b658cd0054..7d7be27a862c2a 100644
--- a/clang/lib/Sema/SemaExprCXX.cpp
+++ b/clang/lib/Sema/SemaExprCXX.cpp
@@ -5843,7 +5843,7 @@ static bool EvaluateBinaryTypeTrait(Sema &Self, TypeTrait BTT, const TypeSourceI
         return false;
 
       if (Self.RequireCompleteType(
-              KeyLoc, RhsT, diag::err_incomplete_type_used_in_type_trait_expr))
+              Rhs->getTypeLoc().getBeginLoc(), RhsT, diag::err_incomplete_type_used_in_type_trait_expr))
         return false;
 
       return BaseInterface->isSuperClassOf(DerivedInterface);
@@ -5866,7 +5866,7 @@ static bool EvaluateBinaryTypeTrait(Sema &Self, TypeTrait BTT, const TypeSourceI
     //   If Base and Derived are class types and are different types
     //   (ignoring possible cv-qualifiers) then Derived shall be a
     //   complete type.
-    if (Self.RequireCompleteType(KeyLoc, RhsT,
+    if (Self.RequireCompleteType(Rhs->getTypeLoc().getBeginLoc(), RhsT,
                           diag::err_incomplete_type_used_in_type_trait_expr))
       return false;
 
@@ -5919,7 +5919,7 @@ static bool EvaluateBinaryTypeTrait(Sema &Self, TypeTrait BTT, const TypeSourceI
       return LhsT->isVoidType();
 
     // A function definition requires a complete, non-abstract return type.
-    if (!Self.isCompleteType(KeyLoc, RhsT) || Self.isAbstractType(KeyLoc, RhsT))
+    if (!Self.isCompleteType(Rhs->getTypeLoc().getBeginLoc(), RhsT) || Self.isAbstractType(Rhs->getTypeLoc().getBeginLoc(), RhsT))
       return false;
 
     // Compute the result of add_rvalue_reference.
@@ -5969,11 +5969,11 @@ static bool EvaluateBinaryTypeTrait(Sema &Self, TypeTrait BTT, const TypeSourceI
     //   For both, T and U shall be complete types, (possibly cv-qualified)
     //   void, or arrays of unknown bound.
     if (!LhsT->isVoidType() && !LhsT->isIncompleteArrayType() &&
-        Self.RequireCompleteType(KeyLoc, LhsT,
+        Self.RequireCompleteType(Lhs->getTypeLoc().getBeginLoc(), LhsT,
           diag::err_incomplete_type_used_in_type_trait_expr))
       return false;
     if (!RhsT->isVoidType() && !RhsT->isIncompleteArrayType() &&
-        Self.RequireCompleteType(KeyLoc, RhsT,
+        Self.RequireCompleteType(Rhs->getTypeLoc().getBeginLoc(), RhsT,
           diag::err_incomplete_type_used_in_type_trait_expr))
       return false;
 
@@ -6029,12 +6029,15 @@ static bool EvaluateBinaryTypeTrait(Sema &Self, TypeTrait BTT, const TypeSourceI
   }
   case BTT_IsLayoutCompatible: {
     if (!LhsT->isVoidType() && !LhsT->isIncompleteArrayType())
-      Self.RequireCompleteType(KeyLoc, LhsT, diag::err_incomplete_type);
+      Self.RequireCompleteType(Lhs->getTypeLoc().getBeginLoc(), LhsT, diag::err_incomplete_type);
     if (!RhsT->isVoidType() && !RhsT->isIncompleteArrayType())
-      Self.RequireCompleteType(KeyLoc, RhsT, diag::err_incomplete_type);
+      Self.RequireCompleteType(Rhs->getTypeLoc().getBeginLoc(), RhsT, diag::err_incomplete_type);
 
-    if (LhsT->isVariableArrayType() || RhsT->isVariableArrayType())
-      Self.Diag(KeyLoc, diag::err_vla_unsupported)
+    if (LhsT->isVariableArrayType())
+      Self.Diag(Lhs->getTypeLoc().getBeginLoc(), diag::err_vla_unsupported)
+          << 1 << tok::kw___is_layout_compatible;
+    if (RhsT->isVariableArrayType())
+      Self.Diag(Rhs->getTypeLoc().getBeginLoc(), diag::err_vla_unsupported)
           << 1 << tok::kw___is_layout_compatible;
     return Self.IsLayoutCompatible(LhsT, RhsT);
   }
diff --git a/clang/test/SemaCXX/type-traits.cpp b/clang/test/SemaCXX/type-traits.cpp
index e29763714341e7..421d3007d27ffe 100644
--- a/clang/test/SemaCXX/type-traits.cpp
+++ b/clang/test/SemaCXX/type-traits.cpp
@@ -1759,6 +1759,7 @@ void is_layout_compatible(int n)
   // expected-error at -1 {{variable length arrays are not supported in '__is_layout_compatible'}}
   static_assert(!__is_layout_compatible(int[n], int[n]));
   // expected-error at -1 {{variable length arrays are not supported in '__is_layout_compatible'}}
+  // expected-error at -2 {{variable length arrays are not supported in '__is_layout_compatible'}}
   static_assert(__is_layout_compatible(int&, int&));
   static_assert(!__is_layout_compatible(int&, char&));
   static_assert(__is_layout_compatible(void(int), void(int)));