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Add section on method resolution regarding supertrait shadowing #2147

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Add section on method resolution regarding supertrait shadowing #2147

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51173be
Add section on method resolution regarding supertrait shadowing
Amanieu Jan 28, 2026
3126639
Add a note on the type-relative resolution stub about shadowing
Amanieu Feb 4, 2026
a26af3f
Spell "subtrait" without hyphen
traviscross Feb 4, 2026
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3 changes: 3 additions & 0 deletions src/expressions/method-call-expr.md
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Expand Up @@ -66,6 +66,9 @@ Then, for each candidate type `T`, search for a [visible] method with a receiver
r[expr.method.ambiguous-target]
If this results in multiple possible candidates, then it is an error, and the receiver must be [converted][disambiguate call] to an appropriate receiver type to make the method call.

r[expr.method.supertrait-shadowing]
As an exception to the above, if all candidates consist of trait methods and one candidate is a subtrait of all other candidates then that candidate is selected instead of causing an ambiguity error.

r[expr.method.receiver-constraints]
This process does not take into account the mutability or lifetime of the receiver, or whether a method is `unsafe`. Once a method is looked up, if it can't be called for one (or more) of those reasons, the result is a compiler error.

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2 changes: 2 additions & 0 deletions src/names/name-resolution.md
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Expand Up @@ -561,6 +561,8 @@ r[names.resolution.type-relative]
> [!NOTE]
> This is a placeholder for future expansion about type-dependent resolution.

- Type-relative name resolution of qualified path expressions shares the shadowing behavior documented in r[expr.method.supertrait-shadowing] on method resolution.

[AST]: glossary.ast
[Builtin attributes]: ./preludes.md#r-names.preludes.lang
[Derive helpers]: ../procedural-macros.md#r-macro.proc.derive.attributes
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