Rollup merge of #88757 - andrewhickman:master, r=jackh726

Suggest wapping expr in parentheses on invalid unary negation

Fixes #88701

src/test/ui/parser/expr-as-stmt.fixed

@@ -32,4 +32,9 @@ fn moo(x: u32) -> bool {
     }) > 0 //~ ERROR expected expression
 }
 
+fn qux() -> u32 {
+    ({2}) - 2 //~ ERROR cannot apply unary operator `-` to type `u32`
+    //~^ ERROR mismatched types
+}
+
 fn main() {}

src/test/ui/parser/expr-as-stmt.rs

@@ -32,4 +32,9 @@ fn moo(x: u32) -> bool {
     } > 0 //~ ERROR expected expression
 }
 
+fn qux() -> u32 {
+    {2} - 2 //~ ERROR cannot apply unary operator `-` to type `u32`
+    //~^ ERROR mismatched types
+}
+
 fn main() {}

src/test/ui/parser/expr-as-stmt.stderr

@@ -99,7 +99,29 @@ help: parentheses are required to parse this as an expression
 LL |     ({ 3 }) * 3
    |     +     +
 
-error: aborting due to 9 previous errors
+error[E0308]: mismatched types
+  --> $DIR/expr-as-stmt.rs:36:6
+   |
+LL |     {2} - 2
+   |      ^ expected `()`, found integer
+   |
+help: you might have meant to return this value
+   |
+LL |     {return 2;} - 2
+   |      ++++++  +
 
-Some errors have detailed explanations: E0308, E0614.
+error[E0600]: cannot apply unary operator `-` to type `u32`
+  --> $DIR/expr-as-stmt.rs:36:9
+   |
+LL |     {2} - 2
+   |         ^^^ cannot apply unary operator `-`
+   |
+help: parentheses are required to parse this as an expression
+   |
+LL |     ({2}) - 2
+   |     +   +
+
+error: aborting due to 11 previous errors
+
+Some errors have detailed explanations: E0308, E0600, E0614.
 For more information about an error, try `rustc --explain E0308`.