[flang] Make implicit conversion explicit in assignment

When intrinsic types are assigned there are some implicit conversions
that take place. This change make them explicit in the types
representation of assignments.

Differential Revision: https://reviews.llvm.org/D79637

diff --git a/flang/lib/Semantics/expression.cpp b/flang/lib/Semantics/expression.cpp
index 9306f70..cc7faef 100644 (file)
--- a/flang/lib/Semantics/expression.cpp
+++ b/flang/lib/Semantics/expression.cpp
@@ -184,6 +184,8 @@ private:
   std::optional<ActualArgument> AnalyzeExpr(const parser::Expr &);
   bool AreConformable() const;
   const Symbol *FindBoundOp(parser::CharBlock, int passIndex);
+  void AddAssignmentConversion(
+      const DynamicType &lhsType, const DynamicType &rhsType);
   bool OkLogicalIntegerAssignment(TypeCategory lhs, TypeCategory rhs);
   std::optional<DynamicType> GetType(std::size_t) const;
   int GetRank(std::size_t) const;
@@ -2809,6 +2811,9 @@ std::optional<ProcedureRef> ArgumentAnalyzer::TryDefinedAssignment() {
   Tristate isDefined{
       semantics::IsDefinedAssignment(lhsType, lhsRank, rhsType, rhsRank)};
   if (isDefined == Tristate::No) {
+    if (lhsType && rhsType) {
+      AddAssignmentConversion(*lhsType, *rhsType);
+    }
     return std::nullopt; // user-defined assignment not allowed for these args
   }
   auto restorer{context_.GetContextualMessages().SetLocation(source_)};
@@ -2939,6 +2944,19 @@ const Symbol *ArgumentAnalyzer::FindBoundOp(
   return result;
 }
 
+// If there is an implicit conversion between intrinsic types, make it explicit
+void ArgumentAnalyzer::AddAssignmentConversion(
+    const DynamicType &lhsType, const DynamicType &rhsType) {
+  if (lhsType.category() == rhsType.category() &&
+      lhsType.kind() == rhsType.kind()) {
+    // no conversion necessary
+  } else if (auto rhsExpr{evaluate::ConvertToType(lhsType, MoveExpr(1))}) {
+    actuals_[1] = ActualArgument{*rhsExpr};
+  } else {
+    actuals_[1] = std::nullopt;
+  }
+}
+
 std::optional<DynamicType> ArgumentAnalyzer::GetType(std::size_t i) const {
   return i < actuals_.size() ? actuals_[i].value().GetType() : std::nullopt;
 }