[all-commits] [llvm/llvm-project] 3c2dc2: [lldb] Also apply Fix-Its in "note:" diagnostics t...

[Raphael Isemann via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 3c2dc28d812c917e01f46b3bcf5b5e0a2a803276
      https://github.com/llvm/llvm-project/commit/3c2dc28d812c917e01f46b3bcf5b5e0a2a803276
  Author: Raphael Isemann <teemperor at gmail.com>
  Date:   2020-04-06 (Mon, 06 Apr 2020)

  Changed paths:
    M lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp
    M lldb/test/API/commands/expression/fixits/TestFixIts.py

  Log Message:
  -----------
  [lldb] Also apply Fix-Its in "note:" diagnostics that belong to an error diagnostic

Summary:
LLDB currently applies Fix-Its if they are attached to a Clang diagnostic that has the
severity "error". Fix-Its connected to warnings and other severities are supposed to
be ignored as LLDB doesn't seem to trust Clang Fix-Its in these situations.

However, LLDB also ignores all Fix-Its coming from "note:" diagnostics. These diagnostics
are usually emitted alongside other diagnostics (both warnings and errors), either to keep
a single diagnostic message shorter or because the Fix-It is in a different source line. As they
are technically their own (non-error) diagnostics, we currently are ignoring all Fix-Its associated with them.

For example, this is a possible Clang diagnostic with a Fix-It that is currently ignored:
```
error: <user expression 1>:2:10: too many arguments provided to function-like macro invocation
ToStr(0, {,})
         ^
<user expression 1>:1:9: macro 'ToStr' defined here
#define ToStr(x) #x
        ^
<user expression 1>:2:1: cannot use initializer list at the beginning of a macro argument
ToStr(0, {,})
^        ~~~~
```

We also don't store "note:" diagnostics at all, as LLDB's abstraction around the whole diagnostic
concept doesn't have such a concept. The text of "note:" diagnostics is instead
appended to the last non-note diagnostic (which is causing that there is no "note:" text in the
diagnostic above, as all the "note:" diagnostics have been appended to the first "error: ..." text).

This patch fixes the ignored Fix-Its in note-diagnostics by appending them to the last non-note
diagnostic, similar to the way we handle the text in these diagnostics.

Reviewers: JDevlieghere, jingham

Reviewed By: JDevlieghere

Subscribers: abidh

Differential Revision: https://reviews.llvm.org/D77055