Teach the VarDeclUsageChecker About Variables Bound in Patterns #33033
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The VDUC was missing a class of AST nodes that can bind variables: patterns in switch statements. For these, it was falling back to requesting a simple replacement of the bound variable name with _. But for patterns, this means there's a two-step dance the user has to go through where the first fixit does this: .pattern(let x) -> .pattern(let _) Then a second round of compilation would emit a fixit to do this: .pattern(let _) -> .pattern(_) Instead, detect "simple" variable bindings - for now, variable patterns that are immediately preceded by a `let` or `var` binding pattern - and collapse two steps into one. Resolves rdar://47240768
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The VDUC was missing a class of AST nodes that can bind variables:
patterns (in switch statements). For these, it was falling back to
requesting a simple replacement of the bound variable name with _. But
for patterns, this means there's a two-step dance the user has to go
through where the first fixit does this:
Then a second round of compilation would emit a fixit to do this:
Instead, detect "simple" variable bindings - for now, variable patterns
that are immediately preceded by a
letorvarbinding pattern - andcollapse two steps into one.
Resolves rdar://47240768