llvm-project

5d01a0ad - [clang][Modules] Fixing Incorrect Diagnostics Issued during By-name Dependency Scanning (#178542)

[clang][Modules] Fixing Incorrect Diagnostics Issued during By-name Dependency Scanning (#178542) The by-name lookup API uses the same diagnostics engine and consumer for multiple lookups. When multiple lookups fail, the diagnostics could be incorrect for all but the first failing lookup. All the subsequent failing lookups inherit the diagnostics from the first failing lookup. This PR resets the diagnostics consumer's buffer and the CompilerInstance's diagnostics engine for each by-name lookup, so each lookup can produce the correct diagnostics. Part of work for rdar://136303612.