diff --git a/src/cargo/core/workspace.rs b/src/cargo/core/workspace.rs
index cd384bef816..7091e216088 100644
--- a/src/cargo/core/workspace.rs
+++ b/src/cargo/core/workspace.rs
@@ -1714,18 +1714,18 @@ impl InheritableFields {
 
     pub fn dependencies(&self) -> CargoResult<BTreeMap<String, TomlDependency>> {
         self.dependencies.clone().map_or(
-            Err(anyhow!("[workspace.dependencies] was not defined")),
+            Err(anyhow!("`workspace.dependencies` was not defined")),
             |d| Ok(d),
         )
     }
 
     pub fn get_dependency(&self, name: &str) -> CargoResult<TomlDependency> {
         self.dependencies.clone().map_or(
-            Err(anyhow!("[workspace.dependencies] was not defined")),
+            Err(anyhow!("`workspace.dependencies` was not defined")),
             |deps| {
                 deps.get(name).map_or(
                     Err(anyhow!(
-                        "dependency {} was not found in [workspace.dependencies]",
+                        "`dependency.{}` was not found in `workspace.dependencies`",
                         name
                     )),
                     |dep| Ok(dep.clone()),
@@ -1737,7 +1737,7 @@ impl InheritableFields {
     pub fn version(&self) -> CargoResult<semver::Version> {
         self.version
             .clone()
-            .map_or(Err(anyhow!("[workspace.version] was not defined")), |d| {
+            .map_or(Err(anyhow!("`workspace.version` was not defined")), |d| {
                 Ok(d)
             })
     }
@@ -1745,14 +1745,14 @@ impl InheritableFields {
     pub fn authors(&self) -> CargoResult<Vec<String>> {
         self.authors
             .clone()
-            .map_or(Err(anyhow!("[workspace.authors] was not defined")), |d| {
+            .map_or(Err(anyhow!("`workspace.authors` was not defined")), |d| {
                 Ok(d)
             })
     }
 
     pub fn description(&self) -> CargoResult<String> {
         self.description.clone().map_or(
-            Err(anyhow!("[workspace.description] was not defined")),
+            Err(anyhow!("`workspace.description` was not defined")),
             |d| Ok(d),
         )
     }
@@ -1760,14 +1760,14 @@ impl InheritableFields {
     pub fn homepage(&self) -> CargoResult<String> {
         self.homepage
             .clone()
-            .map_or(Err(anyhow!("[workspace.homepage] was not defined")), |d| {
+            .map_or(Err(anyhow!("`workspace.homepage` was not defined")), |d| {
                 Ok(d)
             })
     }
 
     pub fn documentation(&self) -> CargoResult<String> {
         self.documentation.clone().map_or(
-            Err(anyhow!("[workspace.documentation] was not defined")),
+            Err(anyhow!("`workspace.documentation` was not defined")),
             |d| Ok(d),
         )
     }
@@ -1775,7 +1775,7 @@ impl InheritableFields {
     pub fn readme(&self) -> CargoResult<StringOrBool> {
         self.readme
             .clone()
-            .map_or(Err(anyhow!("[workspace.readme] was not defined")), |d| {
+            .map_or(Err(anyhow!("`workspace.readme` was not defined")), |d| {
                 Ok(d)
             })
     }
@@ -1783,14 +1783,14 @@ impl InheritableFields {
     pub fn keywords(&self) -> CargoResult<Vec<String>> {
         self.keywords
             .clone()
-            .map_or(Err(anyhow!("[workspace.keywords] was not defined")), |d| {
+            .map_or(Err(anyhow!("`workspace.keywords` was not defined")), |d| {
                 Ok(d)
             })
     }
 
     pub fn categories(&self) -> CargoResult<Vec<String>> {
         self.categories.clone().map_or(
-            Err(anyhow!("[workspace.categories] was not defined")),
+            Err(anyhow!("`workspace.categories` was not defined")),
             |d| Ok(d),
         )
     }
@@ -1798,21 +1798,21 @@ impl InheritableFields {
     pub fn license(&self) -> CargoResult<String> {
         self.license
             .clone()
-            .map_or(Err(anyhow!("[workspace.license] was not defined")), |d| {
+            .map_or(Err(anyhow!("`workspace.license` was not defined")), |d| {
                 Ok(d)
             })
     }
 
     pub fn license_file(&self) -> CargoResult<String> {
         self.license_file.clone().map_or(
-            Err(anyhow!("[workspace.license_file] was not defined")),
+            Err(anyhow!("`workspace.license_file` was not defined")),
             |d| Ok(d),
         )
     }
 
     pub fn repository(&self) -> CargoResult<String> {
         self.repository.clone().map_or(
-            Err(anyhow!("[workspace.repository] was not defined")),
+            Err(anyhow!("`workspace.repository` was not defined")),
             |d| Ok(d),
         )
     }
@@ -1820,7 +1820,7 @@ impl InheritableFields {
     pub fn publish(&self) -> CargoResult<VecStringOrBool> {
         self.publish
             .clone()
-            .map_or(Err(anyhow!("[workspace.publish] was not defined")), |d| {
+            .map_or(Err(anyhow!("`workspace.publish` was not defined")), |d| {
                 Ok(d)
             })
     }
@@ -1828,7 +1828,7 @@ impl InheritableFields {
     pub fn edition(&self) -> CargoResult<String> {
         self.edition
             .clone()
-            .map_or(Err(anyhow!("[workspace.edition] was not defined")), |d| {
+            .map_or(Err(anyhow!("`workspace.edition` was not defined")), |d| {
                 Ok(d)
             })
     }
@@ -1836,7 +1836,7 @@ impl InheritableFields {
     pub fn badges(&self) -> CargoResult<BTreeMap<String, BTreeMap<String, String>>> {
         self.badges
             .clone()
-            .map_or(Err(anyhow!("[workspace.badges] was not defined")), |d| {
+            .map_or(Err(anyhow!("`workspace.badges` was not defined")), |d| {
                 Ok(d)
             })
     }
diff --git a/src/cargo/util/toml/mod.rs b/src/cargo/util/toml/mod.rs
index bd85a94f4c8..b49bdce5139 100644
--- a/src/cargo/util/toml/mod.rs
+++ b/src/cargo/util/toml/mod.rs
@@ -129,7 +129,8 @@ pub fn read_manifest_from_str(
             }
             if let TomlDependency::Workspace(_) = dep {
                 bail!(
-                    "`dependencies.{}` specified `{{ workspace = true}}`, but workspace dependencies cannot do this",
+                    "`workspace.dependencies.{}` specified `{{ workspace = true }}`, but \
+                    workspace dependencies cannot do this",
                     name
                 );
             }
@@ -1010,12 +1011,13 @@ impl<T> MaybeWorkspace<T> {
             MaybeWorkspace::Workspace(TomlWorkspaceField { workspace: true }) => {
                 cargo_features.require(Feature::workspace_inheritance())?;
                 get_ws_field().context(format!(
-                    "error reading `{}` from workspace root manifest's `[workspace.{}]`",
+                    "error inheriting `{}` from workspace root manifest's `workspace.{}`",
                     label, label
                 ))
             }
             MaybeWorkspace::Workspace(TomlWorkspaceField { workspace: false }) => Err(anyhow!(
-                "workspace cannot be false for key `package.{label}`",
+                "`workspace=false` is unsupported for `package.{}`",
+                label,
             )),
         }
     }
@@ -2190,7 +2192,7 @@ impl<P: ResolveToPath + Clone> TomlDependency<P> {
             }) => {
                 cargo_features.require(Feature::workspace_inheritance())?;
                 get_ws_dependency().context(format!(
-                    "error reading `dependencies.{}` from workspace root manifest's `[workspace.dependencies.{}]`",
+                    "error reading `dependencies.{}` from workspace root manifest's `workspace.dependencies.{}`",
                     label, label
                 )).map(|dep| {
                     match dep {
@@ -2200,16 +2202,22 @@ impl<P: ResolveToPath + Clone> TomlDependency<P> {
                             dep.add_features(features);
                             dep.update_optional(optional);
                             TomlDependency::Detailed(dep)
-                        }
-                        // We check for this when we parse a toml file
-                        TomlDependency::Workspace(_) => unreachable!(),
+                        },
+                        TomlDependency::Workspace(_) => {
+                            unreachable!(
+                                "We check that no workspace defines dependencies with \
+                                `{{ workspace = true }}` when we read a manifest from a string. \
+                                this should not happen but did on {}",
+                                label
+                            )
+                        },
                     }
                 })
             }
             TomlDependency::Workspace(TomlWorkspaceDependency {
                 workspace: false, ..
             }) => Err(anyhow!(
-                "workspace cannot be false for key `dependencies.{}`",
+                "`workspace=false` is unsupported for `package.dependencies.{}`",
                 label,
             )),
         }
diff --git a/tests/testsuite/deduplicate_workspace.rs b/tests/testsuite/inheritable_workspace_fields.rs
similarity index 97%
rename from tests/testsuite/deduplicate_workspace.rs
rename to tests/testsuite/inheritable_workspace_fields.rs
index 06535a1a01a..4fa4484ff56 100644
--- a/tests/testsuite/deduplicate_workspace.rs
+++ b/tests/testsuite/inheritable_workspace_fields.rs
@@ -1,4 +1,4 @@
-//! Tests for deduplicating Cargo.toml fields with { workspace = true }
+//! Tests for inheriting Cargo.toml fields with { workspace = true }
 use cargo_test_support::registry::{Dependency, Package};
 use cargo_test_support::{basic_lib_manifest, git, paths, project, publish, registry};
 
@@ -495,10 +495,10 @@ fn inherit_from_own_undefined_field() {
 [ERROR] failed to parse manifest at `[CWD]/Cargo.toml`
 
 Caused by:
-  error reading `description` from workspace root manifest's `[workspace.description]`
+  error inheriting `description` from workspace root manifest's `workspace.description`
 
 Caused by:
-  [workspace.description] was not defined
+  `workspace.description` was not defined
 ",
         )
         .run();
@@ -604,7 +604,7 @@ fn error_on_unimplemented_inheritance_fields() {
 [ERROR] failed to parse manifest at `[CWD]/Cargo.toml`
 
 Caused by:
-  error reading `version` from workspace root manifest's `[workspace.version]`
+  error inheriting `version` from workspace root manifest's `workspace.version`
 
 Caused by:
   inheriting from a parent workspace is not implemented yet
@@ -677,7 +677,7 @@ Caused by:
   failed to parse manifest at `[CWD]/bar/Cargo.toml`
 
 Caused by:
-  error reading `dependencies.detailed` from workspace root manifest's `[workspace.dependencies.detailed]`
+  error reading `dependencies.detailed` from workspace root manifest's `workspace.dependencies.detailed`
 
 Caused by:
   inheriting from a parent workspace is not implemented yet
@@ -724,7 +724,7 @@ fn error_workspace_false() {
 [ERROR] failed to parse manifest at `[CWD]/Cargo.toml`
 
 Caused by:
-  workspace cannot be false for key `package.description`
+  `workspace=false` is unsupported for `package.description`
 ",
         )
         .run();
@@ -768,7 +768,8 @@ fn error_workspace_dependency_looked_for_workspace_itself() {
 [ERROR] failed to parse manifest at `[CWD]/Cargo.toml`
 
 Caused by:
-  `dependencies.dep` specified `{ workspace = true}`, but workspace dependencies cannot do this
+  `workspace.dependencies.dep` specified `{ workspace = true }`, but workspace dependencies \
+  cannot do this
 ",
         )
         .run();
diff --git a/tests/testsuite/main.rs b/tests/testsuite/main.rs
index 3a24015f311..a89324f9f95 100644
--- a/tests/testsuite/main.rs
+++ b/tests/testsuite/main.rs
@@ -39,7 +39,6 @@ mod cross_compile;
 mod cross_publish;
 mod custom_target;
 mod death;
-mod deduplicate_workspace;
 mod dep_info;
 mod directory;
 mod doc;
@@ -58,6 +57,7 @@ mod git_auth;
 mod git_gc;
 mod glob_targets;
 mod help;
+mod inheritable_workspace_fields;
 mod init;
 mod install;
 mod install_upgrade;