llvm-project

9b377fb8 - [LifetimeSafety] Merge lifetimebound attribute on implicit 'this' across method redeclarations (#172146)

[LifetimeSafety] Merge lifetimebound attribute on implicit 'this' across method redeclarations (#172146) Followup on https://github.com/llvm/llvm-project/pull/107627 Fixes https://github.com/llvm/llvm-project/issues/62072 Fixes https://github.com/llvm/llvm-project/issues/172013 Fixes https://github.com/llvm/llvm-project/issues/175391 This PR adds support for merging the `lifetimebound` attribute on the implicit `this` parameter when merging method declarations. Previously, if a method was declared with `lifetimebound` on its function type (which represents the implicit `this` parameter), this attribute would not be propagated to the method definition, causing lifetime safety warnings to be missed. The implementation adds helper functions to extract the `lifetimebound` attribute from a function type and to merge this attribute from an old method declaration to a new one when appropriate.