Author: Haojian Wu Date: 2020-08-28T09:56:52+02:00 New Revision: 5d21aedfdbf0b85d65bad08b7b89913205de4b33
URL: https://github.com/llvm/llvm-project/commit/5d21aedfdbf0b85d65bad08b7b89913205de4b33 DIFF: https://github.com/llvm/llvm-project/commit/5d21aedfdbf0b85d65bad08b7b89913205de4b33.diff LOG: Add release note for RecoveryExpr. Added: Modified: clang/docs/ReleaseNotes.rst Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 7b1df2ed9c3f..83877d0d95a2 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -48,6 +48,46 @@ Major New Features - ... +Recovery AST +^^^^^^^^^^^^ + +clang's AST now improves support for representing broken C++ code. This improves +the quality of subsequent diagnostics after an error is encountered. It also +exposes more information to tools like clang-tidy and clangd that consume +clang’s AST, allowing them to be more accurate on broken code. + +A RecoveryExpr is introduced in clang's AST, marking an expression containing +semantic errors. This preserves the source range and subexpressions of the +broken expression in the AST (rather than discarding the whole expression). + +For the following invalid code: + + .. code-block:: c++ + + int NoArg(); // Line 1 + int x = NoArg(42); // oops! + +clang-10 produces the minimal placeholder: + + .. code-block:: c++ + + // VarDecl <line:2:1, col:5> col:5 x 'int' + +clang-11 produces a richer AST: + + .. code-block:: c++ + + // VarDecl <line:2:1, col:16> col:5 x 'int' cinit + // `-RecoveryExpr <col:9, col:16> '<dependent type>' contains-errors lvalue + // `-UnresolvedLookupExpr <col:9> '<overloaded function>' lvalue (ADL) = 'NoArg' + // `-IntegerLiteral <col:15> 'int' 42 + +Note that error-dependent types and values may now occur outside a template +context. Tools may need to adjust assumptions about dependent code. + +This feature is on by default for C++ code, and can be explicitly controlled +with `-Xclang -f[no-]recovery-ast`. + Improvements to Clang's diagnostics ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
