Index: flang/include/flang/Evaluate/call.h
===================================================================
--- flang/include/flang/Evaluate/call.h
+++ flang/include/flang/Evaluate/call.h
@@ -130,6 +130,13 @@
     dummyIntent_ = intent;
     return *this;
   }
+  std::optional<parser::CharBlock> sourceLocation() const {
+    return sourceLocation_;
+  }
+  ActualArgument &set_sourceLocation(std::optional<parser::CharBlock> at) {
+    sourceLocation_ = at;
+    return *this;
+  }
 
   // Wrap this argument in parentheses
   void Parenthesize();
@@ -148,6 +155,7 @@
   std::optional<parser::CharBlock> keyword_;
   bool isPassedObject_{false};
   common::Intent dummyIntent_{common::Intent::Default};
+  std::optional<parser::CharBlock> sourceLocation_;
 };
 
 using ActualArguments = std::vector<std::optional<ActualArgument>>;
Index: flang/lib/Semantics/check-call.cpp
===================================================================
--- flang/lib/Semantics/check-call.cpp
+++ flang/lib/Semantics/check-call.cpp
@@ -26,6 +26,8 @@
 
 static void CheckImplicitInterfaceArg(
     evaluate::ActualArgument &arg, parser::ContextualMessages &messages) {
+  auto restorer{
+      messages.SetLocation(arg.sourceLocation().value_or(messages.at()))};
   if (auto kw{arg.keyword()}) {
     messages.Say(*kw,
         "Keyword '%s=' may not appear in a reference to a procedure with an implicit interface"_err_en_US,
@@ -525,6 +527,8 @@
     const characteristics::DummyProcedure &dummy, const std::string &dummyName,
     evaluate::FoldingContext &context) {
   parser::ContextualMessages &messages{context.messages()};
+  auto restorer{
+      messages.SetLocation(arg.sourceLocation().value_or(messages.at()))};
   const characteristics::Procedure &interface { dummy.procedure.value() };
   if (const auto *expr{arg.UnwrapExpr()}) {
     bool dummyIsPointer{
@@ -658,6 +662,8 @@
   if (!dummy.name.empty()) {
     dummyName += " '"s + parser::ToLowerCaseLetters(dummy.name) + "='";
   }
+  auto restorer{
+      messages.SetLocation(arg.sourceLocation().value_or(messages.at()))};
   std::visit(
       common::visitors{
           [&](const characteristics::DummyDataObject &object) {
Index: flang/lib/Semantics/expression.cpp
===================================================================
--- flang/lib/Semantics/expression.cpp
+++ flang/lib/Semantics/expression.cpp
@@ -92,6 +92,24 @@
   return std::nullopt;
 }
 
+// Utilities to set a source location, if we have one, on an actual argument,
+// when it is statically present.
+static void SetArgSourceLocation(ActualArgument &x, parser::CharBlock at) {
+  x.set_sourceLocation(at);
+}
+static void SetArgSourceLocation(
+    std::optional<ActualArgument> &x, parser::CharBlock at) {
+  if (x) {
+    x->set_sourceLocation(at);
+  }
+}
+static void SetArgSourceLocation(
+    std::optional<ActualArgument> &x, std::optional<parser::CharBlock> at) {
+  if (x && at) {
+    x->set_sourceLocation(*at);
+  }
+}
+
 class ArgumentAnalyzer {
 public:
   explicit ArgumentAnalyzer(ExpressionAnalyzer &context)
@@ -116,6 +134,7 @@
   }
   void Analyze(const parser::Expr &x) {
     actuals_.emplace_back(AnalyzeExpr(x));
+    SetArgSourceLocation(actuals_.back(), x.source);
     fatalErrors_ |= !actuals_.back();
   }
   void Analyze(const parser::Variable &);
@@ -1072,8 +1091,9 @@
     } else if (kind == MiscKind::KindParamInquiry ||
         kind == MiscKind::LenParamInquiry) {
       // Convert x%KIND -> intrinsic KIND(x), x%LEN -> intrinsic LEN(x)
-      return MakeFunctionRef(
-          name, ActualArguments{ActualArgument{std::move(*base)}});
+      ActualArgument arg{std::move(*base)};
+      SetArgSourceLocation(arg, name);
+      return MakeFunctionRef(name, ActualArguments{std::move(arg)});
     } else {
       DIE("unexpected MiscDetails::Kind");
     }
@@ -3156,6 +3176,7 @@
   if (MaybeExpr expr{context_.Analyze(x)}) {
     if (!IsConstantExpr(*expr)) {
       actuals_.emplace_back(std::move(*expr));
+      SetArgSourceLocation(actuals_.back(), x.GetSource());
       return;
     }
     const Symbol *symbol{GetLastSymbol(*expr)};
@@ -3187,6 +3208,7 @@
   std::visit(common::visitors{
                  [&](const common::Indirection<parser::Expr> &x) {
                    actual = AnalyzeExpr(x.value());
+                   SetArgSourceLocation(actual, x.value().source);
                  },
                  [&](const parser::AltReturnSpec &label) {
                    if (!isSubroutine) {
@@ -3494,13 +3516,17 @@
   if (const Symbol * assumedTypeDummy{AssumedTypeDummy(expr)}) {
     expr.typedExpr.Reset(new GenericExprWrapper{}, GenericExprWrapper::Deleter);
     if (isProcedureCall_) {
-      return ActualArgument{ActualArgument::AssumedType{*assumedTypeDummy}};
+      ActualArgument arg{ActualArgument::AssumedType{*assumedTypeDummy}};
+      SetArgSourceLocation(arg, expr.source);
+      return std::move(arg);
     }
     context_.SayAt(expr.source,
         "TYPE(*) dummy argument may only be used as an actual argument"_err_en_US);
   } else if (MaybeExpr argExpr{AnalyzeExprOrWholeAssumedSizeArray(expr)}) {
     if (isProcedureCall_ || !IsProcedure(*argExpr)) {
-      return ActualArgument{std::move(*argExpr)};
+      ActualArgument arg{std::move(*argExpr)};
+      SetArgSourceLocation(arg, expr.source);
+      return std::move(arg);
     }
     context_.SayAt(expr.source,
         IsFunction(*argExpr) ? "Function call must have argument list"_err_en_US
@@ -3560,7 +3586,12 @@
       lhsType.kind() == rhsType.kind()) {
     // no conversion necessary
   } else if (auto rhsExpr{evaluate::ConvertToType(lhsType, MoveExpr(1))}) {
+    std::optional<parser::CharBlock> source;
+    if (actuals_[1]) {
+      source = actuals_[1]->sourceLocation();
+    }
     actuals_[1] = ActualArgument{*rhsExpr};
+    SetArgSourceLocation(actuals_[1], source);
   } else {
     actuals_[1] = std::nullopt;
   }