Rollup merge of #81046 - rylev:unknown-external-crate, r=estebank

Improve unknown external crate error

This improves error messages when unknown items in the crate root are encountered.

Fixes #63799

r? ```@estebank```

7 files changed, 34 insertions, 4 deletions

diff --git a/src/test/ui/editions/edition-imports-virtual-2015-gated.stderr b/src/test/ui/editions/edition-imports-virtual-2015-gated.stderr
index 56cbd882cca..06605c6f208 100644
--- a/src/test/ui/editions/edition-imports-virtual-2015-gated.stderr
+++ b/src/test/ui/editions/edition-imports-virtual-2015-gated.stderr
@@ -2,7 +2,7 @@ error[E0432]: unresolved import `E`
   --> $DIR/edition-imports-virtual-2015-gated.rs:8:5
    |
 LL |     gen_gated!();
-   |     ^^^^^^^^^^^^^ could not find `E` in `{{root}}`
+   |     ^^^^^^^^^^^^^ could not find `E` in crate root
    |
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
diff --git a/src/test/ui/resolve/crate-called-as-function.rs b/src/test/ui/resolve/crate-called-as-function.rs
new file mode 100644
index 00000000000..e8f52c0c029
--- /dev/null
+++ b/src/test/ui/resolve/crate-called-as-function.rs
@@ -0,0 +1,3 @@
+fn main() {
+    ::foo() //~ cannot find external crate `foo` in the crate root
+}
diff --git a/src/test/ui/resolve/crate-called-as-function.stderr b/src/test/ui/resolve/crate-called-as-function.stderr
new file mode 100644
index 00000000000..eb42349aff1
--- /dev/null
+++ b/src/test/ui/resolve/crate-called-as-function.stderr
@@ -0,0 +1,9 @@
+error[E0425]: cannot find external crate `foo` in the crate root
+  --> $DIR/crate-called-as-function.rs:2:7
+   |
+LL |     ::foo()
+   |       ^^^ not found in the crate root
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0425`.
diff --git a/src/test/ui/resolve/missing-in-namespace.rs b/src/test/ui/resolve/missing-in-namespace.rs
new file mode 100644
index 00000000000..e1dedb072b7
--- /dev/null
+++ b/src/test/ui/resolve/missing-in-namespace.rs
@@ -0,0 +1,4 @@
+fn main() {
+    let _map = std::hahmap::HashMap::new();
+    //~^ ERROR failed to resolve: could not find `hahmap` in `std
+}
diff --git a/src/test/ui/resolve/missing-in-namespace.stderr b/src/test/ui/resolve/missing-in-namespace.stderr
new file mode 100644
index 00000000000..8b292aeda50
--- /dev/null
+++ b/src/test/ui/resolve/missing-in-namespace.stderr
@@ -0,0 +1,14 @@
+error[E0433]: failed to resolve: could not find `hahmap` in `std`
+  --> $DIR/missing-in-namespace.rs:2:29
+   |
+LL |     let _map = std::hahmap::HashMap::new();
+   |                             ^^^^^^^ not found in `std::hahmap`
+   |
+help: consider importing this struct
+   |
+LL | use std::collections::HashMap;
+   |
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0433`.
diff --git a/src/test/ui/rfc-2126-extern-absolute-paths/non-existent-2.rs b/src/test/ui/rfc-2126-extern-absolute-paths/non-existent-2.rs
index 4f53108b3a9..61212f299be 100644
--- a/src/test/ui/rfc-2126-extern-absolute-paths/non-existent-2.rs
+++ b/src/test/ui/rfc-2126-extern-absolute-paths/non-existent-2.rs
@@ -2,5 +2,5 @@
 
 fn main() {
     let s = ::xcrate::S;
-    //~^ ERROR failed to resolve: could not find `xcrate` in `{{root}}`
+    //~^ ERROR failed to resolve: could not find `xcrate` in crate root
 }
diff --git a/src/test/ui/rfc-2126-extern-absolute-paths/non-existent-2.stderr b/src/test/ui/rfc-2126-extern-absolute-paths/non-existent-2.stderr
index 7395d01d8ac..8b2a6933f37 100644
--- a/src/test/ui/rfc-2126-extern-absolute-paths/non-existent-2.stderr
+++ b/src/test/ui/rfc-2126-extern-absolute-paths/non-existent-2.stderr
@@ -1,8 +1,8 @@
-error[E0433]: failed to resolve: could not find `xcrate` in `{{root}}`
+error[E0433]: failed to resolve: could not find `xcrate` in crate root
   --> $DIR/non-existent-2.rs:4:15
    |
 LL |     let s = ::xcrate::S;
-   |               ^^^^^^ could not find `xcrate` in `{{root}}`
+   |               ^^^^^^ could not find `xcrate` in crate root
 
 error: aborting due to previous error