Ignore --diagnostic-width argument when computing hash

Author: shadaj

src/compiler/rust.rs

@@ -1034,6 +1034,7 @@ counted_array!(static ARGS: [ArgInfo<ArgData>; _] = [
     take_arg!("--crate-name", String, CanBeSeparated('='), CrateName),
     take_arg!("--crate-type", ArgCrateTypes, CanBeSeparated('='), CrateType),
     take_arg!("--deny", OsString, CanBeSeparated('='), PassThrough),
+    take_arg!("--diagnostic-width", OsString, CanBeSeparated('='), PassThrough),
     take_arg!("--emit", String, CanBeSeparated('='), Emit),
     take_arg!("--error-format", OsString, CanBeSeparated('='), PassThrough),
     take_arg!("--explain", OsString, CanBeSeparated('='), NotCompilation),
@@ -1452,11 +1453,16 @@ where
             let (mut sortables, rest): (Vec<_>, Vec<_>) = os_string_arguments
                 .iter()
                 // We exclude a few arguments from the hash:
-                //   -L, --extern, --out-dir
+                //   -L, --extern, --out-dir, --diagnostic-width
                 // These contain paths which aren't relevant to the output, and the compiler inputs
                 // in those paths (rlibs and static libs used in the compilation) are used as hash
                 // inputs below.
-                .filter(|&(arg, _)| !(arg == "--extern" || arg == "-L" || arg == "--out-dir"))
+                .filter(|&(arg, _)| {
+                    !(arg == "--extern"
+                        || arg == "-L"
+                        || arg == "--out-dir"
+                        || arg == "--diagnostic-width")
+                })
                 // We also exclude `--target` if it specifies a path to a .json file. The file content
                 // is used as hash input below.
                 // If `--target` specifies a string, it continues to be hashed as part of the arguments.