Error/warning messages should consistently use let...else

I haven't done exhaustive checking on this, but it looks like most error/warning messages use let...else, for example:

rust/compiler/rustc_parse/messages.ftl

Line 299 in 8401398

parse_extra_if_in_let_else = remove the `if` if you meant to write a `let...else` statement
rust/compiler/rustc_mir_build/messages.ftl

Line 191 in 8401398

mir_build_irrefutable_let_patterns_let_else = irrefutable `let...else` {$count ->
rust/compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs

Line 683 in 8401398

err.help("...or use `match` instead of `let...else`");

And, most importantly to me, the next print edition of TRPL is about to go out referring to the feature as let...else.

However, there are some error/warning messages that refer to the feature as let else; I think these should be changed to let...else. Some examples:

rust/compiler/rustc_parse/src/parser/stmt.rs

Line 870 in 8401398

format!("{alternatively}you might have meant to use `let else`"),
rust/compiler/rustc_mir_build/messages.ftl

Line 337 in 8401398

mir_build_suggest_let_else = you might want to use `let else` to handle the {$count ->

There are also a number of places that refer to the feature as let-else, but I'm not sure how many of these are really user facing. Example:

rust/src/doc/style-guide/src/statements.md

Lines 103 to 111 in 8401398

    
           ### else blocks (let-else statements) 
        
           A let statement can contain an `else` component, making it a let-else statement. 
        
           In this case, always apply the same formatting rules to the components preceding 
        
           the `else` block (i.e. the `let pattern: Type = initializer_expr` portion) 
        
           as described [for other let statements](#let-statements). 
        
           Format the entire let-else statement on a single line if all the following are 
        
           true:

@rustbot

@rustbot label A-diagnostics

I think it makes sense given appropriate context. There are two forms that we should stick with:

The name of the construct is "let-else" (this is what the RFC calls it and other docs like Style Guide / RBE).
The "shape" of the construct is let...else.

@rustbot

I'd like to work on this issue @rustbot claim

Rollup merge of rust-lang#149255 - reddevilmidzy:let-else, r=Kivooeo

Unrolled build for #149255

Rollup merge of #149255 - reddevilmidzy:let-else, r=Kivooeo

Navigation Menu

Repository navigation

Error/warning messages should consistently use `let...else` #148772

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

	### else blocks (let-else statements)

	A let statement can contain an `else` component, making it a let-else statement.
	In this case, always apply the same formatting rules to the components preceding
	the `else` block (i.e. the `let pattern: Type = initializer_expr` portion)
	as described [for other let statements](#let-statements).

	Format the entire let-else statement on a single line if all the following are
	true:

Error/warning messages should consistently use let...else #148772

Description

Activity

carols10cents commented on Nov 10, 2025

jieyouxu commented on Nov 10, 2025

jieyouxu commented on Nov 10, 2025

reddevilmidzy commented on Nov 21, 2025

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions

Error/warning messages should consistently use `let...else` #148772