[clangd] Ignore more implicit nodes in computing selection.
Summary:
The DeclRefExpr for the callee of overloaded `operator()` and `operator[]` are
assigned the range of the paren/bracket lists in the AST.
These are better thought of as implicit (at least `()` - `[] is murkier).
But there's no bit on Expr for implicit, so just ignore them on our side.
While here, deal with the case where an implicit stmt (e.g. implicit-this)
is wrapped in an implicit cast. Previously we ignored the statement but not
the cast, and so the cast ended up being selected.
Fixes https://github.com/clangd/clangd/issues/195
Reviewers: kadircet, lh123
Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, usaxena95, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D70194
diff --git a/clang-tools-extra/clangd/Selection.cpp b/clang-tools-extra/clangd/Selection.cpp
index 8451c98..1424825 100644
--- a/clang-tools-extra/clangd/Selection.cpp
+++ b/clang-tools-extra/clangd/Selection.cpp
@@ -10,9 +10,11 @@
#include "Logger.h"
#include "SourceCode.h"
#include "clang/AST/ASTTypeTraits.h"
+#include "clang/AST/Expr.h"
#include "clang/AST/PrettyPrinter.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/AST/TypeLoc.h"
+#include "clang/Basic/OperatorKinds.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/TokenKinds.h"
@@ -145,6 +147,32 @@
}
#endif
+bool isImplicit(const Stmt* S) {
+ // Some Stmts are implicit and shouldn't be traversed, but there's no
+ // "implicit" attribute on Stmt/Expr.
+ // Unwrap implicit casts first if present (other nodes too?).
+ if (auto *ICE = llvm::dyn_cast<ImplicitCastExpr>(S))
+ S = ICE->getSubExprAsWritten();
+ // Implicit this in a MemberExpr is not filtered out by RecursiveASTVisitor.
+ // It would be nice if RAV handled this (!shouldTraverseImplicitCode()).
+ if (auto *CTI = llvm::dyn_cast<CXXThisExpr>(S))
+ if (CTI->isImplicit())
+ return true;
+ // Refs to operator() and [] are (almost?) always implicit as part of calls.
+ if (auto *DRE = llvm::dyn_cast<DeclRefExpr>(S)) {
+ if (auto *FD = llvm::dyn_cast<FunctionDecl>(DRE->getDecl())) {
+ switch (FD->getOverloadedOperator()) {
+ case OO_Call:
+ case OO_Subscript:
+ return true;
+ default:
+ break;
+ }
+ }
+ }
+ return false;
+}
+
// We find the selection by visiting written nodes in the AST, looking for nodes
// that intersect with the selected character range.
//
@@ -210,13 +238,8 @@
}
// Stmt is the same, but this form allows the data recursion optimization.
bool dataTraverseStmtPre(Stmt *X) {
- if (!X)
+ if (!X || isImplicit(X))
return false;
- // Implicit this in a MemberExpr is not filtered out by RecursiveASTVisitor.
- // It would be nice if RAV handled this (!shouldTRaverseImplicitCode()).
- if (auto *CTI = llvm::dyn_cast<CXXThisExpr>(X))
- if (CTI->isImplicit())
- return false;
auto N = DynTypedNode::create(*X);
if (canSafelySkipNode(N))
return false;
