Rollup merge of #73953 - JohnTitor:audit-hidden-sugg, r=estebank

Audit hidden/short code suggestions

Should fix #73641.
Audit uses of `span_suggestion_short` and `tool_only_span_suggestion` (`span_suggestion_hidden` is already tested with `run-rustfix`). Leave some FIXMEs for futher improvements/fixes.
r? @estebank

Author: Manishearth

src/librustc_builtin_macros/format.rs

@@ -280,6 +280,8 @@ impl<'a, 'b> Context<'a, 'b> {
                                 ("x", "LowerHex"),
                                 ("X", "UpperHex"),
                             ] {
+                                // FIXME: rustfix (`run-rustfix`) fails to apply suggestions.
+                                // > "Cannot replace slice of data that was already replaced"
                                 err.tool_only_span_suggestion(
                                     sp,
                                     &format!("use the `{}` trait", name),

src/librustc_parse/parser/diagnostics.rs

@@ -1228,10 +1228,13 @@ impl<'a> Parser<'a> {
                 if let Some(sp) = unmatched.unclosed_span {
                     err.span_label(sp, "unclosed delimiter");
                 }
+                // Backticks should be removed to apply suggestions.
+                let mut delim = delim.to_string();
+                delim.retain(|c| c != '`');
                 err.span_suggestion_short(
                     self.prev_token.span.shrink_to_hi(),
-                    &format!("{} may belong here", delim.to_string()),
-                    delim.to_string(),
+                    &format!("`{}` may belong here", delim),
+                    delim,
                     Applicability::MaybeIncorrect,
                 );
                 if unmatched.found_delim.is_none() {

src/librustc_parse/parser/mod.rs

@@ -699,7 +699,7 @@ impl<'a> Parser<'a> {
                                     // misses a separator.
                                     expect_err
                                         .span_suggestion_short(
-                                            sp,
+                                            self.sess.source_map().next_point(sp),
                                             &format!("missing `{}`", token_str),
                                             token_str,
                                             Applicability::MaybeIncorrect,

src/test/ui/block-expression-remove-semicolon.fixed

@@ -0,0 +1,12 @@
+// run-rustfix
+
+fn foo() -> i32 {
+    0
+}
+
+fn main() {
+    let _x: i32 = {
+        //~^ ERROR mismatched types
+        foo() //~ HELP consider removing this semicolon
+    };
+}

src/test/ui/block-expression-remove-semicolon.rs

@@ -1,9 +1,11 @@
+// run-rustfix
+
 fn foo() -> i32 {
-   0
+    0
 }
 
 fn main() {
-    let x: i32 = {
+    let _x: i32 = {
         //~^ ERROR mismatched types
         foo(); //~ HELP consider removing this semicolon
     };

src/test/ui/block-expression-remove-semicolon.stderr

@@ -1,8 +1,8 @@
 error[E0308]: mismatched types
-  --> $DIR/block-expression-remove-semicolon.rs:6:18
+  --> $DIR/block-expression-remove-semicolon.rs:8:19
    |
-LL |       let x: i32 = {
-   |  __________________^
+LL |       let _x: i32 = {
+   |  ___________________^
 LL | |
 LL | |         foo();
    | |              - help: consider removing this semicolon

src/test/ui/block-result/consider-removing-last-semi.fixed

@@ -0,0 +1,13 @@
+// run-rustfix
+
+pub fn f() -> String {  //~ ERROR mismatched types
+    0u8;
+    "bla".to_string()
+}
+
+pub fn g() -> String {  //~ ERROR mismatched types
+    "this won't work".to_string();
+    "removeme".to_string()
+}
+
+fn main() {}

src/test/ui/block-result/consider-removing-last-semi.rs

@@ -1,9 +1,11 @@
-fn f() -> String {  //~ ERROR mismatched types
+// run-rustfix
+
+pub fn f() -> String {  //~ ERROR mismatched types
     0u8;
     "bla".to_string();
 }
 
-fn g() -> String {  //~ ERROR mismatched types
+pub fn g() -> String {  //~ ERROR mismatched types
     "this won't work".to_string();
     "removeme".to_string();
 }

src/test/ui/block-result/consider-removing-last-semi.stderr

@@ -1,21 +1,21 @@
 error[E0308]: mismatched types
-  --> $DIR/consider-removing-last-semi.rs:1:11
+  --> $DIR/consider-removing-last-semi.rs:3:15
    |
-LL | fn f() -> String {
-   |    -      ^^^^^^ expected struct `std::string::String`, found `()`
-   |    |
-   |    implicitly returns `()` as its body has no tail or `return` expression
+LL | pub fn f() -> String {
+   |        -      ^^^^^^ expected struct `std::string::String`, found `()`
+   |        |
+   |        implicitly returns `()` as its body has no tail or `return` expression
 LL |     0u8;
 LL |     "bla".to_string();
    |                      - help: consider removing this semicolon
 
 error[E0308]: mismatched types
-  --> $DIR/consider-removing-last-semi.rs:6:11
+  --> $DIR/consider-removing-last-semi.rs:8:15
    |
-LL | fn g() -> String {
-   |    -      ^^^^^^ expected struct `std::string::String`, found `()`
-   |    |
-   |    implicitly returns `()` as its body has no tail or `return` expression
+LL | pub fn g() -> String {
+   |        -      ^^^^^^ expected struct `std::string::String`, found `()`
+   |        |
+   |        implicitly returns `()` as its body has no tail or `return` expression
 LL |     "this won't work".to_string();
 LL |     "removeme".to_string();
    |                           - help: consider removing this semicolon

src/test/ui/coercion/coercion-missing-tail-expected-type.fixed

@@ -0,0 +1,16 @@
+// #41425 -- error message "mismatched types" has wrong types
+// run-rustfix
+
+fn plus_one(x: i32) -> i32 { //~ ERROR mismatched types
+    x + 1
+}
+
+fn foo() -> Result<u8, u64> { //~ ERROR mismatched types
+    Ok(1)
+}
+
+fn main() {
+    let x = plus_one(5);
+    let _ = foo();
+    println!("X = {}", x);
+}