[flang] Check for errors when analyzing array constructors

[luporl]

Errors in array constructor values result in the array having
less elements than it should, which can cause other errors that
will confuse the user. Avoid this by not returning an expression
on errors.

Fixes #127425

[llvmbot]

@llvm/pr-subscribers-flang-semantics

Author: Leandro Lupori (luporl)

Changes

Errors in array constructor values result in the array having
less elements than it should, which can cause other errors that
will confuse the user. Avoid this by not returning an expression
on errors.

Fixes #127425

---

Full diff: https://github.com/llvm/llvm-project/pull/173092.diff

2 Files Affected:

• (modified) flang/lib/Semantics/expression.cpp (+4)
• (added) flang/test/Semantics/bug127425.f90 (+8)

diff --git a/flang/lib/Semantics/expression.cpp b/flang/lib/Semantics/expression.cpp
index 6f5d0bf9eb242..0b67d1ae013a2 100644
--- a/flang/lib/Semantics/expression.cpp
+++ b/flang/lib/Semantics/expression.cpp
@@ -2076,11 +2076,15 @@ MaybeExpr ArrayConstructorContext::ToExpr() {
 
 MaybeExpr ExpressionAnalyzer::Analyze(const parser::ArrayConstructor &array) {
   const parser::AcSpec &acSpec{array.v};
+  bool hadAnyFatalError{context_.AnyFatalError()};
   ArrayConstructorContext acContext{
       *this, AnalyzeTypeSpec(acSpec.type, GetFoldingContext())};
   for (const parser::AcValue &value : acSpec.values) {
     acContext.Add(value);
   }
+  if (!hadAnyFatalError && context_.AnyFatalError()) {
+    return std::nullopt;
+  }
   return acContext.ToExpr();
 }
 
diff --git a/flang/test/Semantics/bug127425.f90 b/flang/test/Semantics/bug127425.f90
new file mode 100644
index 0000000000000..b01fabba70135
--- /dev/null
+++ b/flang/test/Semantics/bug127425.f90
@@ -0,0 +1,8 @@
+! RUN: %python %S/test_errors.py %s %flang_fc1
+
+program main
+  pointer (j1,ja)
+  pointer (j2,jb)
+  !ERROR: Values in array constructor must have the same declared type when no explicit type appears
+  if (any((/j1,j2,j3,j4,j5/)/=(/1,2,3,4,5/))) print *,'fail'
+end program main

[ergawy]

Thank @luporl! Just one stop by comment if that's ok.

[ergawy]

Can you please add implicit none and add explicit type declarations for better test readability?

[luporl]

Thanks for the review.
I've added explicit type declarations.