Rollup merge of #78332 - PoignardAzur:doc_E0308, r=camelid

Update description for error E0308

Fixes #76462

r? @camelid

1 files changed, 20 insertions, 12 deletions

diff --git a/compiler/rustc_error_codes/src/error_codes/E0308.md b/compiler/rustc_error_codes/src/error_codes/E0308.md
index e2c40f03019..decee630995 100644
--- a/compiler/rustc_error_codes/src/error_codes/E0308.md
+++ b/compiler/rustc_error_codes/src/error_codes/E0308.md
@@ -1,18 +1,26 @@
 Expected type did not match the received type.
 
-Erroneous code example:
+Erroneous code examples:
 
 ```compile_fail,E0308
-let x: i32 = "I am not a number!";
-//     ~~~   ~~~~~~~~~~~~~~~~~~~~
-//      |             |
-//      |    initializing expression;
-//      |    compiler infers type `&str`
-//      |
-//    type `i32` assigned to variable `x`
+fn plus_one(x: i32) -> i32 {
+    x + 1
+}
+
+plus_one("Not a number");
+//       ^^^^^^^^^^^^^^ expected `i32`, found `&str`
+
+if "Not a bool" {
+// ^^^^^^^^^^^^ expected `bool`, found `&str`
+}
+
+let x: f32 = "Not a float";
+//     ---   ^^^^^^^^^^^^^ expected `f32`, found `&str`
+//     |
+//     expected due to this
 ```
 
-This error occurs when the compiler is unable to infer the concrete type of a
-variable. It can occur in several cases, the most common being a mismatch
-between two types: the type the author explicitly assigned, and the type the
-compiler inferred.
+This error occurs when an expression was used in a place where the compiler
+expected an expression of a different type. It can occur in several cases, the
+most common being when calling a function and passing an argument which has a
+different type than the matching type in the function declaration.