Auto merge of #146044 - estebank:issue-88727, r=chenyukang

Suggest parentheses when `match` or `if` expression in binop is parsed as statement

```
error[E0308]: mismatched types
  --> $DIR/expr-as-stmt.rs:81:5
   |
LL |     match () { _ => true } && match () { _ => true };
   |     ^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found `bool`
   |
help: parentheses are required to parse this as an expression
   |
LL |     (match () { _ => true }) && match () { _ => true };
   |     +                      +
```

Address the common case from rust-lang/rust#88727. The original parse error is still outstanding, but the cases brought up in the thread are resolved.

5 files changed, 270 insertions, 7 deletions

diff --git a/tests/ui/parser/expr-as-stmt-2.rs b/tests/ui/parser/expr-as-stmt-2.rs
index 3a18bdc3b73..4b1f62d8056 100644
--- a/tests/ui/parser/expr-as-stmt-2.rs
+++ b/tests/ui/parser/expr-as-stmt-2.rs
@@ -7,4 +7,25 @@ fn foo(a: Option<u32>, b: Option<u32>) -> bool {
     if let Some(y) = a { true } else { false }
 }
 
-fn main() {}
+fn bar() -> bool {
+    false
+}
+
+fn main() {
+    if true { true } else { false } && true;
+    //~^ ERROR mismatched types
+    //~| ERROR mismatched types
+    if true { true } else { false } && if true { true } else { false };
+    //~^ ERROR mismatched types
+    //~| ERROR mismatched types
+    if true { true } else { false } if true { true } else { false };
+    //~^ ERROR mismatched types
+    //~| ERROR mismatched types
+    if true { bar() } else { bar() } && if true { bar() } else { bar() };
+    //~^ ERROR mismatched types
+    //~| ERROR mismatched types
+    if true { bar() } else { bar() } if true { bar() } else { bar() };
+    //~^ ERROR mismatched types
+    //~| ERROR mismatched types
+    let _ = if true { true } else { false } && true; // ok
+}
diff --git a/tests/ui/parser/expr-as-stmt-2.stderr b/tests/ui/parser/expr-as-stmt-2.stderr
index 2b6314c38ce..f9838ee0299 100644
--- a/tests/ui/parser/expr-as-stmt-2.stderr
+++ b/tests/ui/parser/expr-as-stmt-2.stderr
@@ -7,6 +7,10 @@ LL |     if let Some(x) = a { true } else { false }
    |     |                    expected `()`, found `bool`
    |     expected this to be `()`
    |
+help: parentheses are required to parse this as an expression
+   |
+LL |     (if let Some(x) = a { true } else { false })
+   |     +                                          +
 help: you might have meant to return this value
    |
 LL |     if let Some(x) = a { return true; } else { false }
@@ -21,6 +25,10 @@ LL |     if let Some(x) = a { true } else { false }
    |     |                                  expected `()`, found `bool`
    |     expected this to be `()`
    |
+help: parentheses are required to parse this as an expression
+   |
+LL |     (if let Some(x) = a { true } else { false })
+   |     +                                          +
 help: you might have meant to return this value
    |
 LL |     if let Some(x) = a { true } else { return false; }
@@ -41,6 +49,152 @@ help: parentheses are required to parse this as an expression
 LL |     (if let Some(x) = a { true } else { false })
    |     +                                          +
 
-error: aborting due to 3 previous errors
+error[E0308]: mismatched types
+  --> $DIR/expr-as-stmt-2.rs:15:15
+   |
+LL |     if true { true } else { false } && true;
+   |     ----------^^^^-----------------
+   |     |         |
+   |     |         expected `()`, found `bool`
+   |     expected this to be `()`
+   |
+help: parentheses are required to parse this as an expression
+   |
+LL |     (if true { true } else { false }) && true;
+   |     +                               +
+
+error[E0308]: mismatched types
+  --> $DIR/expr-as-stmt-2.rs:15:29
+   |
+LL |     if true { true } else { false } && true;
+   |     ------------------------^^^^^--
+   |     |                       |
+   |     |                       expected `()`, found `bool`
+   |     expected this to be `()`
+   |
+help: parentheses are required to parse this as an expression
+   |
+LL |     (if true { true } else { false }) && true;
+   |     +                               +
+
+error[E0308]: mismatched types
+  --> $DIR/expr-as-stmt-2.rs:18:15
+   |
+LL |     if true { true } else { false } && if true { true } else { false };
+   |     ----------^^^^-----------------
+   |     |         |
+   |     |         expected `()`, found `bool`
+   |     expected this to be `()`
+   |
+help: parentheses are required to parse this as an expression
+   |
+LL |     (if true { true } else { false }) && if true { true } else { false };
+   |     +                               +
+
+error[E0308]: mismatched types
+  --> $DIR/expr-as-stmt-2.rs:18:29
+   |
+LL |     if true { true } else { false } && if true { true } else { false };
+   |     ------------------------^^^^^--
+   |     |                       |
+   |     |                       expected `()`, found `bool`
+   |     expected this to be `()`
+   |
+help: parentheses are required to parse this as an expression
+   |
+LL |     (if true { true } else { false }) && if true { true } else { false };
+   |     +                               +
+
+error[E0308]: mismatched types
+  --> $DIR/expr-as-stmt-2.rs:21:15
+   |
+LL |     if true { true } else { false } if true { true } else { false };
+   |     ----------^^^^-----------------
+   |     |         |
+   |     |         expected `()`, found `bool`
+   |     expected this to be `()`
+
+error[E0308]: mismatched types
+  --> $DIR/expr-as-stmt-2.rs:21:29
+   |
+LL |     if true { true } else { false } if true { true } else { false };
+   |     ------------------------^^^^^--
+   |     |                       |
+   |     |                       expected `()`, found `bool`
+   |     expected this to be `()`
+
+error[E0308]: mismatched types
+  --> $DIR/expr-as-stmt-2.rs:24:15
+   |
+LL |     if true { bar() } else { bar() } && if true { bar() } else { bar() };
+   |     ----------^^^^^-----------------
+   |     |         |
+   |     |         expected `()`, found `bool`
+   |     expected this to be `()`
+   |
+help: parentheses are required to parse this as an expression
+   |
+LL |     (if true { bar() } else { bar() }) && if true { bar() } else { bar() };
+   |     +                                +
+help: consider using a semicolon here
+   |
+LL |     if true { bar() } else { bar() }; && if true { bar() } else { bar() };
+   |                                     +
+
+error[E0308]: mismatched types
+  --> $DIR/expr-as-stmt-2.rs:24:30
+   |
+LL |     if true { bar() } else { bar() } && if true { bar() } else { bar() };
+   |     -------------------------^^^^^--
+   |     |                        |
+   |     |                        expected `()`, found `bool`
+   |     expected this to be `()`
+   |
+help: parentheses are required to parse this as an expression
+   |
+LL |     (if true { bar() } else { bar() }) && if true { bar() } else { bar() };
+   |     +                                +
+help: consider using a semicolon here
+   |
+LL |     if true { bar() } else { bar() }; && if true { bar() } else { bar() };
+   |                                     +
+
+error[E0308]: mismatched types
+  --> $DIR/expr-as-stmt-2.rs:27:15
+   |
+LL |     if true { bar() } else { bar() } if true { bar() } else { bar() };
+   |     ----------^^^^^-----------------
+   |     |         |
+   |     |         expected `()`, found `bool`
+   |     expected this to be `()`
+   |
+help: consider using a semicolon here
+   |
+LL |     if true { bar(); } else { bar() } if true { bar() } else { bar() };
+   |                    +
+help: consider using a semicolon here
+   |
+LL |     if true { bar() } else { bar() }; if true { bar() } else { bar() };
+   |                                     +
+
+error[E0308]: mismatched types
+  --> $DIR/expr-as-stmt-2.rs:27:30
+   |
+LL |     if true { bar() } else { bar() } if true { bar() } else { bar() };
+   |     -------------------------^^^^^--
+   |     |                        |
+   |     |                        expected `()`, found `bool`
+   |     expected this to be `()`
+   |
+help: consider using a semicolon here
+   |
+LL |     if true { bar() } else { bar(); } if true { bar() } else { bar() };
+   |                                   +
+help: consider using a semicolon here
+   |
+LL |     if true { bar() } else { bar() }; if true { bar() } else { bar() };
+   |                                     +
+
+error: aborting due to 13 previous errors
 
 For more information about this error, try `rustc --explain E0308`.
diff --git a/tests/ui/parser/expr-as-stmt.fixed b/tests/ui/parser/expr-as-stmt.fixed
index 0a4d62a4a0c..bfae55047ed 100644
--- a/tests/ui/parser/expr-as-stmt.fixed
+++ b/tests/ui/parser/expr-as-stmt.fixed
@@ -66,7 +66,7 @@ fn asteroids() -> impl FnOnce() -> bool {
 
 // https://github.com/rust-lang/rust/issues/105179
 fn r#match() -> i32 {
-    (match () { () => 1 }) + match () { () => 1 } //~ ERROR expected expression, found `+`
+    ((match () { () => 1 })) + match () { () => 1 } //~ ERROR expected expression, found `+`
     //~^ ERROR mismatched types
 }
 
@@ -76,4 +76,13 @@ fn r#unsafe() -> i32 {
     //~^ ERROR mismatched types
 }
 
+// https://github.com/rust-lang/rust/issues/88727
+fn matches() -> bool {
+    (match () { _ => true }) && match () { _ => true }; //~ ERROR mismatched types
+    (match () { _ => true }) && match () { _ => true }; //~ ERROR mismatched types
+    //~^ ERROR expected `;`, found keyword `match`
+    (match () { _ => true }) && true; //~ ERROR mismatched types
+    ((match () { _ => true })) && true //~ ERROR mismatched types
+    //~^ ERROR mismatched types
+}
 fn main() {}
diff --git a/tests/ui/parser/expr-as-stmt.rs b/tests/ui/parser/expr-as-stmt.rs
index 99c85e65baa..94917432cb0 100644
--- a/tests/ui/parser/expr-as-stmt.rs
+++ b/tests/ui/parser/expr-as-stmt.rs
@@ -76,4 +76,13 @@ fn r#unsafe() -> i32 {
     //~^ ERROR mismatched types
 }
 
+// https://github.com/rust-lang/rust/issues/88727
+fn matches() -> bool {
+    match () { _ => true } && match () { _ => true }; //~ ERROR mismatched types
+    match () { _ => true } && match () { _ => true } //~ ERROR mismatched types
+    //~^ ERROR expected `;`, found keyword `match`
+    match () { _ => true } && true; //~ ERROR mismatched types
+    match () { _ => true } && true //~ ERROR mismatched types
+    //~^ ERROR mismatched types
+}
 fn main() {}
diff --git a/tests/ui/parser/expr-as-stmt.stderr b/tests/ui/parser/expr-as-stmt.stderr
index 577c3455a71..4681129baba 100644
--- a/tests/ui/parser/expr-as-stmt.stderr
+++ b/tests/ui/parser/expr-as-stmt.stderr
@@ -77,6 +77,15 @@ help: parentheses are required to parse this as an expression
 LL |     (unsafe { 1 }) + unsafe { 1 }
    |     +            +
 
+error: expected `;`, found keyword `match`
+  --> $DIR/expr-as-stmt.rs:82:53
+   |
+LL |     match () { _ => true } && match () { _ => true }
+   |                                                     ^ help: add `;` here
+LL |
+LL |     match () { _ => true } && true;
+   |     ----- unexpected token
+
 error[E0308]: mismatched types
   --> $DIR/expr-as-stmt.rs:64:7
    |
@@ -227,9 +236,12 @@ error[E0308]: mismatched types
   --> $DIR/expr-as-stmt.rs:69:5
    |
 LL |     match () { () => 1 } + match () { () => 1 }
-   |     ^^^^^^^^^^^^^^^^^^^^- help: consider using a semicolon here
-   |     |
-   |     expected `()`, found integer
+   |     ^^^^^^^^^^^^^^^^^^^^ expected `()`, found integer
+   |
+help: parentheses are required to parse this as an expression
+   |
+LL |     (match () { () => 1 }) + match () { () => 1 }
+   |     +                    +
 
 error[E0308]: mismatched types
   --> $DIR/expr-as-stmt.rs:75:14
@@ -242,7 +254,65 @@ help: you might have meant to return this value
 LL |     unsafe { return 1; } + unsafe { 1 }
    |              ++++++  +
 
-error: aborting due to 22 previous errors
+error[E0308]: mismatched types
+  --> $DIR/expr-as-stmt.rs:81:5
+   |
+LL |     match () { _ => true } && match () { _ => true };
+   |     ^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found `bool`
+   |
+help: parentheses are required to parse this as an expression
+   |
+LL |     (match () { _ => true }) && match () { _ => true };
+   |     +                      +
+
+error[E0308]: mismatched types
+  --> $DIR/expr-as-stmt.rs:82:5
+   |
+LL |     match () { _ => true } && match () { _ => true }
+   |     ^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found `bool`
+   |
+help: parentheses are required to parse this as an expression
+   |
+LL |     (match () { _ => true }) && match () { _ => true }
+   |     +                      +
+
+error[E0308]: mismatched types
+  --> $DIR/expr-as-stmt.rs:84:5
+   |
+LL |     match () { _ => true } && true;
+   |     ^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found `bool`
+   |
+help: parentheses are required to parse this as an expression
+   |
+LL |     (match () { _ => true }) && true;
+   |     +                      +
+
+error[E0308]: mismatched types
+  --> $DIR/expr-as-stmt.rs:85:5
+   |
+LL |     match () { _ => true } && true
+   |     ^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found `bool`
+   |
+help: parentheses are required to parse this as an expression
+   |
+LL |     (match () { _ => true }) && true
+   |     +                      +
+
+error[E0308]: mismatched types
+  --> $DIR/expr-as-stmt.rs:85:28
+   |
+LL | fn matches() -> bool {
+   |                 ---- expected `bool` because of return type
+...
+LL |     match () { _ => true } && true
+   |                            ^^^^^^^ expected `bool`, found `&&bool`
+   |
+help: parentheses are required to parse this as an expression
+   |
+LL |     (match () { _ => true }) && true
+   |     +                      +
+
+error: aborting due to 28 previous errors
 
 Some errors have detailed explanations: E0308, E0600, E0614.
 For more information about an error, try `rustc --explain E0308`.