Auto merge of #104875 - chenyukang:yukang/fix-104867-inc, r=estebank

Properly handle postfix inc/dec in standalone and subexpr scenarios

Fixes #104867
r? `@estebank`

7 files changed, 360 insertions, 22 deletions

diff --git a/src/test/ui/parser/increment-autofix-2.fixed b/src/test/ui/parser/increment-autofix-2.fixed
new file mode 100644
index 00000000000..580ebaf5dbb
--- /dev/null
+++ b/src/test/ui/parser/increment-autofix-2.fixed
@@ -0,0 +1,63 @@
+// run-rustfix
+
+struct Foo {
+    bar: Bar,
+}
+
+struct Bar {
+    qux: i32,
+}
+
+pub fn post_regular() {
+    let mut i = 0;
+    i += 1; //~ ERROR Rust has no postfix increment operator
+    println!("{}", i);
+}
+
+pub fn post_while() {
+    let mut i = 0;
+    while { let tmp = i; i += 1; tmp } < 5 {
+        //~^ ERROR Rust has no postfix increment operator
+        println!("{}", i);
+    }
+}
+
+pub fn post_regular_tmp() {
+    let mut tmp = 0;
+    tmp += 1; //~ ERROR Rust has no postfix increment operator
+    println!("{}", tmp);
+}
+
+pub fn post_while_tmp() {
+    let mut tmp = 0;
+    while { let tmp_ = tmp; tmp += 1; tmp_ } < 5 {
+        //~^ ERROR Rust has no postfix increment operator
+        println!("{}", tmp);
+    }
+}
+
+pub fn post_field() {
+    let mut foo = Foo { bar: Bar { qux: 0 } };
+    foo.bar.qux += 1;
+    //~^ ERROR Rust has no postfix increment operator
+    println!("{}", foo.bar.qux);
+}
+
+pub fn post_field_tmp() {
+    struct S {
+        tmp: i32
+    }
+    let mut s = S { tmp: 0 };
+    s.tmp += 1;
+    //~^ ERROR Rust has no postfix increment operator
+    println!("{}", s.tmp);
+}
+
+pub fn pre_field() {
+    let mut foo = Foo { bar: Bar { qux: 0 } };
+    foo.bar.qux += 1;
+    //~^ ERROR Rust has no prefix increment operator
+    println!("{}", foo.bar.qux);
+}
+
+fn main() {}
diff --git a/src/test/ui/parser/increment-notfixed.rs b/src/test/ui/parser/increment-autofix-2.rs
index 15f159e53d2..ebe5fa6ca1e 100644
--- a/src/test/ui/parser/increment-notfixed.rs
+++ b/src/test/ui/parser/increment-autofix-2.rs
@@ -1,3 +1,5 @@
+// run-rustfix
+
 struct Foo {
     bar: Bar,
 }
@@ -35,7 +37,7 @@ pub fn post_while_tmp() {
 }
 
 pub fn post_field() {
-    let foo = Foo { bar: Bar { qux: 0 } };
+    let mut foo = Foo { bar: Bar { qux: 0 } };
     foo.bar.qux++;
     //~^ ERROR Rust has no postfix increment operator
     println!("{}", foo.bar.qux);
@@ -45,14 +47,14 @@ pub fn post_field_tmp() {
     struct S {
         tmp: i32
     }
-    let s = S { tmp: 0 };
+    let mut s = S { tmp: 0 };
     s.tmp++;
     //~^ ERROR Rust has no postfix increment operator
     println!("{}", s.tmp);
 }
 
 pub fn pre_field() {
-    let foo = Foo { bar: Bar { qux: 0 } };
+    let mut foo = Foo { bar: Bar { qux: 0 } };
     ++foo.bar.qux;
     //~^ ERROR Rust has no prefix increment operator
     println!("{}", foo.bar.qux);
diff --git a/src/test/ui/parser/increment-notfixed.stderr b/src/test/ui/parser/increment-autofix-2.stderr
index ae55ae06714..11e985480d6 100644
--- a/src/test/ui/parser/increment-notfixed.stderr
+++ b/src/test/ui/parser/increment-autofix-2.stderr
@@ -1,18 +1,16 @@
 error: Rust has no postfix increment operator
-  --> $DIR/increment-notfixed.rs:11:6
+  --> $DIR/increment-autofix-2.rs:13:6
    |
 LL |     i++;
    |      ^^ not a valid postfix operator
    |
 help: use `+= 1` instead
    |
-LL |     { let tmp = i; i += 1; tmp };
-   |     +++++++++++  ~~~~~~~~~~~~~~~
 LL |     i += 1;
    |       ~~~~
 
 error: Rust has no postfix increment operator
-  --> $DIR/increment-notfixed.rs:17:12
+  --> $DIR/increment-autofix-2.rs:19:12
    |
 LL |     while i++ < 5 {
    |     -----  ^^ not a valid postfix operator
@@ -23,24 +21,20 @@ help: use `+= 1` instead
    |
 LL |     while { let tmp = i; i += 1; tmp } < 5 {
    |           +++++++++++  ~~~~~~~~~~~~~~~
-LL |     while i += 1 < 5 {
-   |             ~~~~
 
 error: Rust has no postfix increment operator
-  --> $DIR/increment-notfixed.rs:25:8
+  --> $DIR/increment-autofix-2.rs:27:8
    |
 LL |     tmp++;
    |        ^^ not a valid postfix operator
    |
 help: use `+= 1` instead
    |
-LL |     { let tmp_ = tmp; tmp += 1; tmp_ };
-   |     ++++++++++++    ~~~~~~~~~~~~~~~~~~
 LL |     tmp += 1;
    |         ~~~~
 
 error: Rust has no postfix increment operator
-  --> $DIR/increment-notfixed.rs:31:14
+  --> $DIR/increment-autofix-2.rs:33:14
    |
 LL |     while tmp++ < 5 {
    |     -----    ^^ not a valid postfix operator
@@ -51,37 +45,31 @@ help: use `+= 1` instead
    |
 LL |     while { let tmp_ = tmp; tmp += 1; tmp_ } < 5 {
    |           ++++++++++++    ~~~~~~~~~~~~~~~~~~
-LL |     while tmp += 1 < 5 {
-   |               ~~~~
 
 error: Rust has no postfix increment operator
-  --> $DIR/increment-notfixed.rs:39:16
+  --> $DIR/increment-autofix-2.rs:41:16
    |
 LL |     foo.bar.qux++;
    |                ^^ not a valid postfix operator
    |
 help: use `+= 1` instead
    |
-LL |     { let tmp = foo.bar.qux; foo.bar.qux += 1; tmp };
-   |     +++++++++++            ~~~~~~~~~~~~~~~~~~~~~~~~~
 LL |     foo.bar.qux += 1;
    |                 ~~~~
 
 error: Rust has no postfix increment operator
-  --> $DIR/increment-notfixed.rs:49:10
+  --> $DIR/increment-autofix-2.rs:51:10
    |
 LL |     s.tmp++;
    |          ^^ not a valid postfix operator
    |
 help: use `+= 1` instead
    |
-LL |     { let tmp = s.tmp; s.tmp += 1; tmp };
-   |     +++++++++++      ~~~~~~~~~~~~~~~~~~~
 LL |     s.tmp += 1;
    |           ~~~~
 
 error: Rust has no prefix increment operator
-  --> $DIR/increment-notfixed.rs:56:5
+  --> $DIR/increment-autofix-2.rs:58:5
    |
 LL |     ++foo.bar.qux;
    |     ^^ not a valid prefix operator
diff --git a/src/test/ui/parser/issue-104867-inc-dec-2.rs b/src/test/ui/parser/issue-104867-inc-dec-2.rs
new file mode 100644
index 00000000000..a006421a975
--- /dev/null
+++ b/src/test/ui/parser/issue-104867-inc-dec-2.rs
@@ -0,0 +1,52 @@
+fn test1() {
+    let mut i = 0;
+    let _ = i + ++i; //~ ERROR Rust has no prefix increment operator
+}
+
+fn test2() {
+    let mut i = 0;
+    let _ = ++i + i; //~ ERROR Rust has no prefix increment operator
+}
+
+fn test3() {
+    let mut i = 0;
+    let _ = ++i + ++i; //~ ERROR Rust has no prefix increment operator
+}
+
+fn test4() {
+    let mut i = 0;
+    let _ = i + i++; //~ ERROR Rust has no postfix increment operator
+    // won't suggest since we can not handle the precedences
+}
+
+fn test5() {
+    let mut i = 0;
+    let _ = i++ + i; //~ ERROR Rust has no postfix increment operator
+}
+
+fn test6() {
+    let mut i = 0;
+    let _ = i++ + i++; //~ ERROR Rust has no postfix increment operator
+}
+
+fn test7() {
+    let mut i = 0;
+    let _ = ++i + i++; //~ ERROR Rust has no prefix increment operator
+}
+
+fn test8() {
+    let mut i = 0;
+    let _ = i++ + ++i; //~ ERROR Rust has no postfix increment operator
+}
+
+fn test9() {
+    let mut i = 0;
+    let _ = (1 + 2 + i)++; //~ ERROR Rust has no postfix increment operator
+}
+
+fn test10() {
+    let mut i = 0;
+    let _ = (i++ + 1) + 2; //~ ERROR Rust has no postfix increment operator
+}
+
+fn main() { }
diff --git a/src/test/ui/parser/issue-104867-inc-dec-2.stderr b/src/test/ui/parser/issue-104867-inc-dec-2.stderr
new file mode 100644
index 00000000000..4e2d0546851
--- /dev/null
+++ b/src/test/ui/parser/issue-104867-inc-dec-2.stderr
@@ -0,0 +1,107 @@
+error: Rust has no prefix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:3:17
+   |
+LL |     let _ = i + ++i;
+   |                 ^^ not a valid prefix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = i + { i += 1; i };
+   |                 ~   +++++++++
+
+error: Rust has no prefix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:8:13
+   |
+LL |     let _ = ++i + i;
+   |             ^^ not a valid prefix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = { i += 1; i } + i;
+   |             ~   +++++++++
+
+error: Rust has no prefix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:13:13
+   |
+LL |     let _ = ++i + ++i;
+   |             ^^ not a valid prefix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = { i += 1; i } + ++i;
+   |             ~   +++++++++
+
+error: Rust has no postfix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:18:18
+   |
+LL |     let _ = i + i++;
+   |                  ^^ not a valid postfix operator
+
+error: Rust has no postfix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:24:14
+   |
+LL |     let _ = i++ + i;
+   |              ^^ not a valid postfix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = { let tmp = i; i += 1; tmp } + i;
+   |             +++++++++++  ~~~~~~~~~~~~~~~
+
+error: Rust has no postfix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:29:14
+   |
+LL |     let _ = i++ + i++;
+   |              ^^ not a valid postfix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = { let tmp = i; i += 1; tmp } + i++;
+   |             +++++++++++  ~~~~~~~~~~~~~~~
+
+error: Rust has no prefix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:34:13
+   |
+LL |     let _ = ++i + i++;
+   |             ^^ not a valid prefix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = { i += 1; i } + i++;
+   |             ~   +++++++++
+
+error: Rust has no postfix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:39:14
+   |
+LL |     let _ = i++ + ++i;
+   |              ^^ not a valid postfix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = { let tmp = i; i += 1; tmp } + ++i;
+   |             +++++++++++  ~~~~~~~~~~~~~~~
+
+error: Rust has no postfix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:44:24
+   |
+LL |     let _ = (1 + 2 + i)++;
+   |                        ^^ not a valid postfix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = { let tmp = (1 + 2 + i); (1 + 2 + i) += 1; tmp };
+   |             +++++++++++            ~~~~~~~~~~~~~~~~~~~~~~~~~
+
+error: Rust has no postfix increment operator
+  --> $DIR/issue-104867-inc-dec-2.rs:49:15
+   |
+LL |     let _ = (i++ + 1) + 2;
+   |               ^^ not a valid postfix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     let _ = ({ let tmp = i; i += 1; tmp } + 1) + 2;
+   |              +++++++++++  ~~~~~~~~~~~~~~~
+
+error: aborting due to 10 previous errors
+
diff --git a/src/test/ui/parser/issue-104867-inc-dec.rs b/src/test/ui/parser/issue-104867-inc-dec.rs
new file mode 100644
index 00000000000..760c67b4bed
--- /dev/null
+++ b/src/test/ui/parser/issue-104867-inc-dec.rs
@@ -0,0 +1,45 @@
+struct S {
+    x: i32,
+}
+
+fn test1() {
+    let mut i = 0;
+    i++; //~ ERROR Rust has no postfix increment operator
+}
+
+fn test2() {
+    let s = S { x: 0 };
+    s.x++; //~ ERROR Rust has no postfix increment operator
+}
+
+fn test3() {
+    let mut i = 0;
+    if i++ == 1 {} //~ ERROR Rust has no postfix increment operator
+}
+
+fn test4() {
+    let mut i = 0;
+    ++i; //~ ERROR Rust has no prefix increment operator
+}
+
+fn test5() {
+    let mut i = 0;
+    if ++i == 1 { } //~ ERROR Rust has no prefix increment operator
+}
+
+fn test6() {
+    let mut i = 0;
+    loop { break; }
+    i++; //~ ERROR Rust has no postfix increment operator
+    loop { break; }
+    ++i;
+}
+
+fn test7() {
+    let mut i = 0;
+    loop { break; }
+    ++i; //~ ERROR Rust has no prefix increment operator
+}
+
+
+fn main() {}
diff --git a/src/test/ui/parser/issue-104867-inc-dec.stderr b/src/test/ui/parser/issue-104867-inc-dec.stderr
new file mode 100644
index 00000000000..78bfd3e82f0
--- /dev/null
+++ b/src/test/ui/parser/issue-104867-inc-dec.stderr
@@ -0,0 +1,81 @@
+error: Rust has no postfix increment operator
+  --> $DIR/issue-104867-inc-dec.rs:7:6
+   |
+LL |     i++;
+   |      ^^ not a valid postfix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     i += 1;
+   |       ~~~~
+
+error: Rust has no postfix increment operator
+  --> $DIR/issue-104867-inc-dec.rs:12:8
+   |
+LL |     s.x++;
+   |        ^^ not a valid postfix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     s.x += 1;
+   |         ~~~~
+
+error: Rust has no postfix increment operator
+  --> $DIR/issue-104867-inc-dec.rs:17:9
+   |
+LL |     if i++ == 1 {}
+   |         ^^ not a valid postfix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     if { let tmp = i; i += 1; tmp } == 1 {}
+   |        +++++++++++  ~~~~~~~~~~~~~~~
+
+error: Rust has no prefix increment operator
+  --> $DIR/issue-104867-inc-dec.rs:22:5
+   |
+LL |     ++i;
+   |     ^^ not a valid prefix operator
+   |
+help: use `+= 1` instead
+   |
+LL -     ++i;
+LL +     i += 1;
+   |
+
+error: Rust has no prefix increment operator
+  --> $DIR/issue-104867-inc-dec.rs:27:8
+   |
+LL |     if ++i == 1 { }
+   |        ^^ not a valid prefix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     if { i += 1; i } == 1 { }
+   |        ~   +++++++++
+
+error: Rust has no postfix increment operator
+  --> $DIR/issue-104867-inc-dec.rs:33:6
+   |
+LL |     i++;
+   |      ^^ not a valid postfix operator
+   |
+help: use `+= 1` instead
+   |
+LL |     i += 1;
+   |       ~~~~
+
+error: Rust has no prefix increment operator
+  --> $DIR/issue-104867-inc-dec.rs:41:5
+   |
+LL |     ++i;
+   |     ^^ not a valid prefix operator
+   |
+help: use `+= 1` instead
+   |
+LL -     ++i;
+LL +     i += 1;
+   |
+
+error: aborting due to 7 previous errors
+