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//===--- ExprContextAnalysis.h - Expession context analysis ---------------===//
// This source file is part of the open source project
// Copyright (c) 2019 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
// See for license information
// See for the list of Swift project authors
#include "swift/AST/Type.h"
#include "swift/AST/Types.h"
#include "swift/Basic/LLVM.h"
#include "swift/Basic/SourceLoc.h"
namespace swift {
class DeclContext;
class Expr;
class ValueDecl;
namespace ide {
enum class SemanticContextKind;
/// Type check parent contexts of the given decl context, and the body of the
/// given context until \c Loc if the context is a function body.
void typeCheckContextAt(DeclContext *DC, SourceLoc Loc);
/// From \p DC, find and returns the outer most expression which source range is
/// exact the same as \p TargetRange. Returns \c nullptr if not found.
Expr *findParsedExpr(const DeclContext *DC, SourceRange TargetRange);
/// Remove \c CodeCompletionExpr from \p expr . Returns \c true if it actually
/// mutated the expression.
/// NOTE: Currently, this only removes CodeCompletionExpr at call argument
/// position.
bool removeCodeCompletionExpr(ASTContext &Ctx, Expr *&expr);
/// Collects possible expected return types of the given decl context.
/// \p DC should be an \c AbstractFunctionDecl or an \c AbstractClosureExpr.
void collectPossibleReturnTypesFromContext(DeclContext *DC,
SmallVectorImpl<Type> &candidates);
struct FunctionTypeAndDecl {
AnyFunctionType *Type;
ValueDecl *Decl;
Optional<SemanticContextKind> SemanticContext;
FunctionTypeAndDecl(AnyFunctionType *Type, ValueDecl *Decl)
: Type(Type), Decl(Decl) {}
FunctionTypeAndDecl(AnyFunctionType *Type, ValueDecl *Decl,
SemanticContextKind SemanticContext)
: Type(Type), Decl(Decl), SemanticContext(SemanticContext) {}
struct PossibleParamInfo {
/// Expected parameter.
/// 'nullptr' indicates that the code completion position is at out of
/// expected argument position. E.g.
/// func foo(x: Int) {}
/// foo(x: 1, <HERE>)
const AnyFunctionType::Param *Param;
bool IsRequired;
PossibleParamInfo(const AnyFunctionType::Param *Param, bool IsRequired)
: Param(Param), IsRequired(IsRequired) {
assert((Param || !IsRequired) &&
"nullptr with required flag is not allowed");
/// Given an expression and its decl context, the analyzer tries to figure out
/// the expected type of the expression by analyzing its context.
class ExprContextInfo {
SmallVector<Type, 2> PossibleTypes;
SmallVector<PossibleParamInfo, 2> PossibleParams;
SmallVector<FunctionTypeAndDecl, 2> PossibleCallees;
Expr *AnalyzedExpr = nullptr;
bool implicitSingleExpressionReturn = false;
ExprContextInfo(DeclContext *DC, Expr *TargetExpr);
// Returns a list of possible context types.
ArrayRef<Type> getPossibleTypes() const { return PossibleTypes; }
/// Whether the type context comes from a single-expression body without
/// and explicit return e.g. `foo({ <here> })` and not foo({ return <here>}).
/// Since the input may be incomplete, such as in code-completion, take into
/// account that the types returned by `getPossibleTypes()` are only a hint.
bool isImplicitSingleExpressionReturn() const {
return implicitSingleExpressionReturn;
// Returns a list of possible argument label names.
// Valid only if \c getKind() is \c CallArgument.
ArrayRef<PossibleParamInfo> getPossibleParams() const {
return PossibleParams;
// Returns a list of possible callee
// Valid only if \c getKind() is \c CallArgument.
ArrayRef<FunctionTypeAndDecl> getPossibleCallees() const {
return PossibleCallees;
Expr *getAnalyzedExpr() const {
return AnalyzedExpr;
} // namespace ide
} // namespace swift