Auto merge of rust-lang#141066 - matthiaskrgr:rollup-e7tyrj5, r=matthiaskrgr

Rollup of 9 pull requests

Successful merges:

 - rust-lang#140791 (std: explain prefer `TryInto` over `TryFrom` when specifying traits bounds on generic function)
 - rust-lang#140834 (move (or remove) some impl Trait tests)
 - rust-lang#140910 (Remove `stable` attribute from wasi fs (read_exact|write_all)_at)
 - rust-lang#140984 (fix doc for UnixStream)
 - rust-lang#140997 (Add negative test coverage for `-Clink-self-contained` and `-Zlinker-features`)
 - rust-lang#141003 (Improve ternary operator recovery)
 - rust-lang#141009 (Migrate to modern datetime API)
 - rust-lang#141013 (Implement methods to set STARTUPINFO flags for Command API on Windows)
 - rust-lang#141026 (rustc-dev-guide subtree update)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

compiler/rustc_parse/messages.ftl

@@ -815,7 +815,6 @@ parse_switch_ref_box_order = switch the order of `ref` and `box`
     .suggestion = swap them
 
 parse_ternary_operator = Rust has no ternary operator
-    .help = use an `if-else` expression instead
 
 parse_tilde_is_not_unary_operator = `~` cannot be used as a unary operator
     .suggestion = use `!` to perform bitwise not
@@ -963,6 +962,8 @@ parse_use_empty_block_not_semi = expected { "`{}`" }, found `;`
 parse_use_eq_instead = unexpected `==`
     .suggestion = try using `=` instead
 
+parse_use_if_else = use an `if-else` expression instead
+
 parse_use_let_not_auto = write `let` instead of `auto` to introduce a new variable
 parse_use_let_not_var = write `let` instead of `var` to introduce a new variable
 

compiler/rustc_parse/src/errors.rs

@@ -436,10 +436,28 @@ pub(crate) enum IfExpressionMissingThenBlockSub {
 
 #[derive(Diagnostic)]
 #[diag(parse_ternary_operator)]
-#[help]
 pub(crate) struct TernaryOperator {
     #[primary_span]
     pub span: Span,
+    /// If we have a span for the condition expression, suggest the if/else
+    #[subdiagnostic]
+    pub sugg: Option<TernaryOperatorSuggestion>,
+    /// Otherwise, just print the suggestion message
+    #[help(parse_use_if_else)]
+    pub no_sugg: bool,
+}
+
+#[derive(Subdiagnostic, Copy, Clone)]
+#[multipart_suggestion(parse_use_if_else, applicability = "maybe-incorrect", style = "verbose")]
+pub(crate) struct TernaryOperatorSuggestion {
+    #[suggestion_part(code = "if ")]
+    pub before_cond: Span,
+    #[suggestion_part(code = "{{")]
+    pub question: Span,
+    #[suggestion_part(code = "}} else {{")]
+    pub colon: Span,
+    #[suggestion_part(code = " }}")]
+    pub end: Span,
 }
 
 #[derive(Subdiagnostic)]