225 lines
		
	
	
		
			8.3 KiB
		
	
	
	
		
			C++
		
	
	
	
			
		
		
	
	
			225 lines
		
	
	
		
			8.3 KiB
		
	
	
	
		
			C++
		
	
	
	
| //===-- lib/Semantics/check-data.cpp --------------------------------------===//
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| //
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| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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| // See https://llvm.org/LICENSE.txt for license information.
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| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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| //
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| //===----------------------------------------------------------------------===//
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| 
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| // DATA statement semantic analysis.
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| // - Applies static semantic checks to the variables in each data-stmt-set with
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| //   class DataVarChecker;
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| // - Invokes conversion of DATA statement values to static initializers
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| 
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| #include "check-data.h"
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| #include "data-to-inits.h"
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| #include "flang/Evaluate/traverse.h"
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| #include "flang/Parser/parse-tree.h"
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| #include "flang/Parser/tools.h"
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| #include "flang/Semantics/tools.h"
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| #include <algorithm>
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| #include <vector>
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| 
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| namespace Fortran::semantics {
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| 
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| // Ensures that references to an implied DO loop control variable are
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| // represented as such in the "body" of the implied DO loop.
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| void DataChecker::Enter(const parser::DataImpliedDo &x) {
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|   auto name{std::get<parser::DataImpliedDo::Bounds>(x.t).name.thing.thing};
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|   int kind{evaluate::ResultType<evaluate::ImpliedDoIndex>::kind};
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|   if (const auto dynamicType{evaluate::DynamicType::From(*name.symbol)}) {
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|     if (dynamicType->category() == TypeCategory::Integer) {
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|       kind = dynamicType->kind();
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|     }
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|   }
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|   exprAnalyzer_.AddImpliedDo(name.source, kind);
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| }
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| 
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| void DataChecker::Leave(const parser::DataImpliedDo &x) {
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|   auto name{std::get<parser::DataImpliedDo::Bounds>(x.t).name.thing.thing};
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|   exprAnalyzer_.RemoveImpliedDo(name.source);
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| }
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| 
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| // DataVarChecker applies static checks once to each variable that appears
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| // in a data-stmt-set.  These checks are independent of the values that
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| // correspond to the variables.
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| class DataVarChecker : public evaluate::AllTraverse<DataVarChecker, true> {
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| public:
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|   using Base = evaluate::AllTraverse<DataVarChecker, true>;
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|   DataVarChecker(SemanticsContext &c, parser::CharBlock src)
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|       : Base{*this}, context_{c}, source_{src} {}
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|   using Base::operator();
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|   bool HasComponentWithoutSubscripts() const {
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|     return hasComponent_ && !hasSubscript_;
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|   }
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|   bool operator()(const Symbol &symbol) { // C876
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|     // 8.6.7p(2) - precludes non-pointers of derived types with
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|     // default component values
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|     const Scope &scope{context_.FindScope(source_)};
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|     bool isFirstSymbol{isFirstSymbol_};
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|     isFirstSymbol_ = false;
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|     if (const char *whyNot{IsAutomatic(symbol) ? "Automatic variable"
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|                 : IsDummy(symbol)              ? "Dummy argument"
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|                 : IsFunctionResult(symbol)     ? "Function result"
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|                 : IsAllocatable(symbol)        ? "Allocatable"
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|                 : IsInitialized(symbol, true)  ? "Default-initialized"
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|                 : IsInBlankCommon(symbol)      ? "Blank COMMON object"
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|                 : IsProcedure(symbol) && !IsPointer(symbol) ? "Procedure"
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|                 // remaining checks don't apply to components
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|                 : !isFirstSymbol                  ? nullptr
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|                 : IsHostAssociated(symbol, scope) ? "Host-associated object"
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|                 : IsUseAssociated(symbol, scope)  ? "USE-associated object"
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|                                                   : nullptr}) {
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|       context_.Say(source_,
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|           "%s '%s' must not be initialized in a DATA statement"_err_en_US,
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|           whyNot, symbol.name());
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|       return false;
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|     } else if (IsProcedurePointer(symbol)) {
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|       context_.Say(source_,
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|           "Procedure pointer '%s' in a DATA statement is not standard"_en_US,
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|           symbol.name());
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|     }
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|     return true;
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|   }
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|   bool operator()(const evaluate::Component &component) {
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|     hasComponent_ = true;
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|     const Symbol &lastSymbol{component.GetLastSymbol()};
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|     if (isPointerAllowed_) {
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|       if (IsPointer(lastSymbol) && hasSubscript_) { // C877
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|         context_.Say(source_,
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|             "Rightmost data object pointer '%s' must not be subscripted"_err_en_US,
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|             lastSymbol.name().ToString());
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|         return false;
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|       }
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|       RestrictPointer();
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|     } else {
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|       if (IsPointer(lastSymbol)) { // C877
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|         context_.Say(source_,
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|             "Data object must not contain pointer '%s' as a non-rightmost part"_err_en_US,
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|             lastSymbol.name().ToString());
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|         return false;
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|       }
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|     }
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|     return (*this)(component.base()) && (*this)(lastSymbol);
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|   }
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|   bool operator()(const evaluate::ArrayRef &arrayRef) {
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|     hasSubscript_ = true;
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|     return (*this)(arrayRef.base()) && (*this)(arrayRef.subscript());
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|   }
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|   bool operator()(const evaluate::Substring &substring) {
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|     hasSubscript_ = true;
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|     return (*this)(substring.parent()) && (*this)(substring.lower()) &&
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|         (*this)(substring.upper());
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|   }
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|   bool operator()(const evaluate::CoarrayRef &) { // C874
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|     context_.Say(
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|         source_, "Data object must not be a coindexed variable"_err_en_US);
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|     return false;
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|   }
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|   bool operator()(const evaluate::Subscript &subs) {
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|     DataVarChecker subscriptChecker{context_, source_};
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|     subscriptChecker.RestrictPointer();
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|     return std::visit(
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|                common::visitors{
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|                    [&](const evaluate::IndirectSubscriptIntegerExpr &expr) {
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|                      return CheckSubscriptExpr(expr);
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|                    },
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|                    [&](const evaluate::Triplet &triplet) {
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|                      return CheckSubscriptExpr(triplet.lower()) &&
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|                          CheckSubscriptExpr(triplet.upper()) &&
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|                          CheckSubscriptExpr(triplet.stride());
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|                    },
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|                },
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|                subs.u) &&
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|         subscriptChecker(subs.u);
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|   }
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|   template <typename T>
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|   bool operator()(const evaluate::FunctionRef<T> &) const { // C875
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|     context_.Say(source_,
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|         "Data object variable must not be a function reference"_err_en_US);
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|     return false;
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|   }
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|   void RestrictPointer() { isPointerAllowed_ = false; }
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| 
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| private:
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|   bool CheckSubscriptExpr(
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|       const std::optional<evaluate::IndirectSubscriptIntegerExpr> &x) const {
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|     return !x || CheckSubscriptExpr(*x);
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|   }
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|   bool CheckSubscriptExpr(
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|       const evaluate::IndirectSubscriptIntegerExpr &expr) const {
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|     return CheckSubscriptExpr(expr.value());
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|   }
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|   bool CheckSubscriptExpr(
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|       const evaluate::Expr<evaluate::SubscriptInteger> &expr) const {
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|     if (!evaluate::IsConstantExpr(expr)) { // C875,C881
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|       context_.Say(
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|           source_, "Data object must have constant subscripts"_err_en_US);
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|       return false;
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|     } else {
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|       return true;
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|     }
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|   }
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| 
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|   SemanticsContext &context_;
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|   parser::CharBlock source_;
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|   bool hasComponent_{false};
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|   bool hasSubscript_{false};
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|   bool isPointerAllowed_{true};
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|   bool isFirstSymbol_{true};
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| };
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| 
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| void DataChecker::Leave(const parser::DataIDoObject &object) {
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|   if (const auto *designator{
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|           std::get_if<parser::Scalar<common::Indirection<parser::Designator>>>(
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|               &object.u)}) {
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|     if (MaybeExpr expr{exprAnalyzer_.Analyze(*designator)}) {
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|       auto source{designator->thing.value().source};
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|       if (evaluate::IsConstantExpr(*expr)) { // C878,C879
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|         exprAnalyzer_.context().Say(
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|             source, "Data implied do object must be a variable"_err_en_US);
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|       } else {
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|         DataVarChecker checker{exprAnalyzer_.context(), source};
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|         if (checker(*expr)) {
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|           if (checker.HasComponentWithoutSubscripts()) { // C880
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|             exprAnalyzer_.context().Say(source,
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|                 "Data implied do structure component must be subscripted"_err_en_US);
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|           } else {
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|             return;
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|           }
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|         }
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|       }
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|     }
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|     currentSetHasFatalErrors_ = true;
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|   }
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| }
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| 
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| void DataChecker::Leave(const parser::DataStmtObject &dataObject) {
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|   std::visit(common::visitors{
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|                  [](const parser::DataImpliedDo &) { // has own Enter()/Leave()
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|                  },
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|                  [&](const auto &var) {
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|                    auto expr{exprAnalyzer_.Analyze(var)};
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|                    if (!expr ||
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|                        !DataVarChecker{exprAnalyzer_.context(),
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|                            parser::FindSourceLocation(dataObject)}(*expr)) {
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|                      currentSetHasFatalErrors_ = true;
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|                    }
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|                  },
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|              },
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|       dataObject.u);
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| }
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| 
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| void DataChecker::Leave(const parser::DataStmtSet &set) {
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|   if (!currentSetHasFatalErrors_) {
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|     AccumulateDataInitializations(inits_, exprAnalyzer_, set);
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|   }
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|   currentSetHasFatalErrors_ = false;
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| }
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| 
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| void DataChecker::CompileDataInitializationsIntoInitializers() {
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|   ConvertToInitializers(inits_, exprAnalyzer_);
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| }
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| 
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| } // namespace Fortran::semantics
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