[flang] Improve error message on bad complex literal.

[klausler]

A complex literal constant can have one BOZ component, since the type and value of the literal can be determined by converting the BOZ value to the type of the other component. But a complex literal constant with two BOZ components doesn't have a well-defined type. The error message was confusing in the case; emit a better one.

Fixes #124201.

[llvmbot]

@llvm/pr-subscribers-flang-semantics

Author: Peter Klausler (klausler)

Changes

A complex literal constant can have one BOZ component, since the type and value of the literal can be determined by converting the BOZ value to the type of the other component. But a complex literal constant with two BOZ components doesn't have a well-defined type. The error message was confusing in the case; emit a better one.

Fixes #124201.

---

Full diff: https://github.com/llvm/llvm-project/pull/124331.diff

2 Files Affected:

• (modified) flang/lib/Evaluate/tools.cpp (+5)
• (modified) flang/test/Semantics/complex01.f90 (+3-1)

diff --git a/flang/lib/Evaluate/tools.cpp b/flang/lib/Evaluate/tools.cpp
index 2d0e1996632fc2..16b02607190973 100644
--- a/flang/lib/Evaluate/tools.cpp
+++ b/flang/lib/Evaluate/tools.cpp
@@ -212,6 +212,11 @@ ConvertRealOperandsResult ConvertRealOperands(
             return {AsSameKindExprs<TypeCategory::Real>(
                 ConvertTo(ry, std::move(bx)), std::move(ry))};
           },
+          [&](BOZLiteralConstant &&,
+              BOZLiteralConstant &&) -> ConvertRealOperandsResult {
+            messages.Say("operands cannot both be BOZ"_err_en_US);
+            return std::nullopt;
+          },
           [&](auto &&, auto &&) -> ConvertRealOperandsResult { // C718
             messages.Say(
                 "operands must be INTEGER, UNSIGNED, REAL, or BOZ"_err_en_US);
diff --git a/flang/test/Semantics/complex01.f90 b/flang/test/Semantics/complex01.f90
index c9d408ee0e111f..d268eafa685896 100644
--- a/flang/test/Semantics/complex01.f90
+++ b/flang/test/Semantics/complex01.f90
@@ -1,5 +1,5 @@
 ! RUN: %python %S/test_errors.py %s %flang_fc1
-! C718 Each named constant in a complex literal constant shall be of type 
+! C718 Each named constant in a complex literal constant shall be of type
 ! integer or real.
 subroutine s()
   integer :: ivar = 35
@@ -30,4 +30,6 @@ subroutine s()
   complex :: cvar11 = (cconst, 1.0)
   !ERROR: operands must be INTEGER, UNSIGNED, REAL, or BOZ
   complex :: cvar12 = (lconst, 1.0)
+  !ERROR: operands cannot both be BOZ
+  complex :: cvar13 = (z'3f700000', z'00000000')
 end subroutine s

[eugeneepshteyn]

Is there already a test for creating COMPLEX from one BOZ component?

[klausler]

I don't know.

[DanielCChen]

LGTM.