Rollup merge of #105872 - chenyukang:yukang/fix-105494-remove-method-call, r=eholk

Suggest remove last method call when type coerce with expected  type

Fixes #105494

2 files changed, 76 insertions, 0 deletions

diff --git a/src/test/ui/suggestions/issue-105494.rs b/src/test/ui/suggestions/issue-105494.rs
new file mode 100644
index 00000000000..8b409232c20
--- /dev/null
+++ b/src/test/ui/suggestions/issue-105494.rs
@@ -0,0 +1,22 @@
+fn test1() {
+    let _v: i32 = (1 as i32).to_string(); //~ ERROR mismatched types
+
+    // won't suggestion
+    let _v: i32 = (1 as i128).to_string(); //~ ERROR mismatched types
+
+    let _v: &str = "foo".to_string(); //~ ERROR mismatched types
+}
+
+fn test2() {
+    let mut path: String = "/usr".to_string();
+    let folder: String = "lib".to_string();
+
+    path = format!("{}/{}", path, folder).as_str(); //~ ERROR mismatched types
+
+    println!("{}", &path);
+}
+
+fn main() {
+    test1();
+    test2();
+}
diff --git a/src/test/ui/suggestions/issue-105494.stderr b/src/test/ui/suggestions/issue-105494.stderr
new file mode 100644
index 00000000000..5aa3f2af738
--- /dev/null
+++ b/src/test/ui/suggestions/issue-105494.stderr
@@ -0,0 +1,54 @@
+error[E0308]: mismatched types
+  --> $DIR/issue-105494.rs:2:19
+   |
+LL |     let _v: i32 = (1 as i32).to_string();
+   |             ---   ^^^^^^^^^^^^^^^^^^^^^^ expected `i32`, found struct `String`
+   |             |
+   |             expected due to this
+   |
+help: try removing the method call
+   |
+LL -     let _v: i32 = (1 as i32).to_string();
+LL +     let _v: i32 = (1 as i32);
+   |
+
+error[E0308]: mismatched types
+  --> $DIR/issue-105494.rs:5:19
+   |
+LL |     let _v: i32 = (1 as i128).to_string();
+   |             ---   ^^^^^^^^^^^^^^^^^^^^^^^ expected `i32`, found struct `String`
+   |             |
+   |             expected due to this
+
+error[E0308]: mismatched types
+  --> $DIR/issue-105494.rs:7:20
+   |
+LL |     let _v: &str = "foo".to_string();
+   |             ----   ^^^^^^^^^^^^^^^^^ expected `&str`, found struct `String`
+   |             |
+   |             expected due to this
+   |
+help: try removing the method call
+   |
+LL -     let _v: &str = "foo".to_string();
+LL +     let _v: &str = "foo";
+   |
+
+error[E0308]: mismatched types
+  --> $DIR/issue-105494.rs:14:12
+   |
+LL |     let mut path: String = "/usr".to_string();
+   |                   ------ expected due to this type
+...
+LL |     path = format!("{}/{}", path, folder).as_str();
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected struct `String`, found `&str`
+   |
+help: try removing the method call
+   |
+LL -     path = format!("{}/{}", path, folder).as_str();
+LL +     path = format!("{}/{}", path, folder);
+   |
+
+error: aborting due to 4 previous errors
+
+For more information about this error, try `rustc --explain E0308`.