Show patch location in error message.

Author: ehuss

src/cargo/core/registry.rs

@@ -812,16 +812,18 @@ fn summary_for_patch(
     };
     if found.is_empty() {
         anyhow::bail!(
-            "The patch location does not appear to contain any packages \
+            "The patch location `{}` does not appear to contain any packages \
             matching the name `{}`.",
+            orig_patch.source_id(),
             orig_patch.package_name()
         );
     } else {
         anyhow::bail!(
-            "The patch location contains a `{}` package with {}, but the patch \
+            "The patch location `{}` contains a `{}` package with {}, but the patch \
             definition requires `{}`.\n\
             Check that the version in the patch location is what you expect, \
             and update the patch definition to match.",
+            orig_patch.source_id(),
             orig_patch.package_name(),
             found,
             orig_patch.version_req()

tests/testsuite/patch.rs

@@ -1614,7 +1614,7 @@ Caused by:
   patch for `bar` in `https://github.com/rust-lang/crates.io-index` did not resolve to any crates
 
 Caused by:
-  The patch location does not appear to contain any packages matching the name `bar`.
+  The patch location `[..]/foo/bar` does not appear to contain any packages matching the name `bar`.
 ",
         )
         .run();
@@ -1653,7 +1653,7 @@ Caused by:
   patch for `bar` in `https://github.com/rust-lang/crates.io-index` did not resolve to any crates
 
 Caused by:
-  The patch location contains a `bar` package with version `0.1.0`, \
+  The patch location `[..]/foo/bar` contains a `bar` package with version `0.1.0`, \
 but the patch definition requires `^0.1.1`.
 Check that the version in the patch location is what you expect, \
 and update the patch definition to match.
@@ -1763,7 +1763,7 @@ Caused by:
   patch for `bar` in `https://github.com/rust-lang/crates.io-index` did not resolve to any crates
 
 Caused by:
-  The patch location contains a `bar` package with version `0.1.0`, but the patch definition requires `^0.1.1`.
+  The patch location `[..]/foo/bar` contains a `bar` package with version `0.1.0`, but the patch definition requires `^0.1.1`.
 Check that the version in the patch location is what you expect, and update the patch definition to match.
 ",
         )