Add compiletest directive show-std-source

Signed-off-by: xizheyin <xizheyin@smail.nju.edu.cn>

Author: xizheyin

src/tools/compiletest/src/directives.rs

@@ -197,6 +197,10 @@ pub struct TestProps {
     /// Build and use `minicore` as `core` stub for `no_core` tests in cross-compilation scenarios
     /// that don't otherwise want/need `-Z build-std`.
     pub add_core_stubs: bool,
+    /// Whether to show std library source code in error messages and backtraces.
+    /// When false (default), std source paths are remapped to "/rustc/FAKE_PREFIX".
+    /// When true, actual std source paths are shown.
+    pub show_std_source: bool,
     /// Whether line annotatins are required for the given error kind.
     pub dont_require_annotations: HashSet<ErrorKind>,
 }
@@ -245,6 +249,7 @@ mod directives {
     pub const FILECHECK_FLAGS: &'static str = "filecheck-flags";
     pub const NO_AUTO_CHECK_CFG: &'static str = "no-auto-check-cfg";
     pub const ADD_CORE_STUBS: &'static str = "add-core-stubs";
+    pub const SHOW_STD_SOURCE: &'static str = "show-std-source";
     // This isn't a real directive, just one that is probably mistyped often
     pub const INCORRECT_COMPILER_FLAGS: &'static str = "compiler-flags";
 }
@@ -301,6 +306,7 @@ impl TestProps {
             no_auto_check_cfg: false,
             has_enzyme: false,
             add_core_stubs: false,
+            show_std_source: false,
             dont_require_annotations: Default::default(),
         }
     }
@@ -588,6 +594,8 @@ impl TestProps {
 
                     self.update_add_core_stubs(ln, config);
 
+                    config.set_name_directive(ln, SHOW_STD_SOURCE, &mut self.show_std_source);
+
                     if let Some(err_kind) =
                         config.parse_name_value_directive(ln, DONT_REQUIRE_ANNOTATIONS)
                     {
@@ -1027,6 +1035,7 @@ const KNOWN_DIRECTIVE_NAMES: &[&str] = &[
     "rustfix-only-machine-applicable",
     "should-fail",
     "should-ice",
+    "show-std-source",
     "stderr-per-bitwidth",
     "test-mir-pass",
     "unique-doc-out-dir",

src/tools/compiletest/src/runtest.rs

@@ -1522,16 +1522,18 @@ impl<'test> TestCx<'test> {
         // Use a single thread for efficiency and a deterministic error message order
         rustc.arg("-Zthreads=1");
 
-        // Hide libstd sources from ui tests to make sure we generate the stderr
-        // output that users will see.
-        // Without this, we may be producing good diagnostics in-tree but users
-        // will not see half the information.
-        //
-        // This also has the benefit of more effectively normalizing output between different
-        // compilers, so that we don't have to know the `/rustc/$sha` output to normalize after the
-        // fact.
-        rustc.arg("-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX");
-        rustc.arg("-Ztranslate-remapped-path-to-local-path=no");
+        if !self.props.show_std_source {
+            // Hide libstd sources from ui tests to make sure we generate the stderr
+            // output that users will see.
+            // Without this, we may be producing good diagnostics in-tree but users
+            // will not see half the information.
+            //
+            // This also has the benefit of more effectively normalizing output between different
+            // compilers, so that we don't have to know the `/rustc/$sha` output to normalize after the
+            // fact.
+            rustc.arg("-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX");
+            rustc.arg("-Ztranslate-remapped-path-to-local-path=no");
+        }
 
         // Hide Cargo dependency sources from ui tests to make sure the error message doesn't
         // change depending on whether $CARGO_HOME is remapped or not. If this is not present,

tests/ui/compiletest-self-test/show-std-source-without-flag.rs

@@ -0,0 +1,22 @@
+// This test without //@ show-std-source directive, as a contrast to show-std-source.rs
+
+enum Foo<T> {
+    Bar {
+        v23: T,
+        y: isize
+    }
+}
+
+fn f(x: &Foo) { //~ ERROR missing generics for enum `Foo` [E0107]
+    match *x {
+        Foo::Bar { y: y, v23: x } => {
+            assert_eq!(x, 1);
+            assert_eq!(y, 2); //~ ERROR can't compare `&isize` with `{integer}` [E0277]
+        }
+    }
+}
+
+pub fn main() {
+    let x = Foo::Bar { x: 1, y: 2 }; //~ ERROR variant `Foo<_>::Bar` has no field named `x` [E0559]
+    f(&x);
+}

tests/ui/compiletest-self-test/show-std-source-without-flag.stderr

@@ -0,0 +1,37 @@
+error[E0107]: missing generics for enum `Foo`
+  --> $DIR/show-std-source-without-flag.rs:10:10
+   |
+LL | fn f(x: &Foo) {
+   |          ^^^ expected 1 generic argument
+   |
+note: enum defined here, with 1 generic parameter: `T`
+  --> $DIR/show-std-source-without-flag.rs:3:6
+   |
+LL | enum Foo<T> {
+   |      ^^^ -
+help: add missing generic argument
+   |
+LL | fn f(x: &Foo<T>) {
+   |             +++
+
+error[E0277]: can't compare `&isize` with `{integer}`
+  --> $DIR/show-std-source-without-flag.rs:14:13
+   |
+LL |             assert_eq!(y, 2);
+   |             ^^^^^^^^^^^^^^^^ no implementation for `&isize == {integer}`
+   |
+   = help: the trait `PartialEq<{integer}>` is not implemented for `&isize`
+   = note: this error originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0559]: variant `Foo<_>::Bar` has no field named `x`
+  --> $DIR/show-std-source-without-flag.rs:20:24
+   |
+LL |     let x = Foo::Bar { x: 1, y: 2 };
+   |                        ^ `Foo<_>::Bar` does not have this field
+   |
+   = note: available fields are: `v23`
+
+error: aborting due to 3 previous errors
+
+Some errors have detailed explanations: E0107, E0277, E0559.
+For more information about an error, try `rustc --explain E0107`.

tests/ui/compiletest-self-test/show-std-source.rs

@@ -0,0 +1,24 @@
+// This test with //@ show-std-source directive,
+// as a contrast to show-std-source-without-flag.rs
+//@ show-std-source
+
+enum Foo<T> {
+    Bar {
+        v23: T,
+        y: isize
+    }
+}
+
+fn f(x: &Foo) { //~ ERROR missing generics for enum `Foo` [E0107]
+    match *x {
+        Foo::Bar { y: y, v23: x } => {
+            assert_eq!(x, 1);
+            assert_eq!(y, 2); //~ ERROR can't compare `&isize` with `{integer}` [E0277]
+        }
+    }
+}
+
+pub fn main() {
+    let x = Foo::Bar { x: 1, y: 2 }; //~ ERROR variant `Foo<_>::Bar` has no field named `x` [E0559]
+    f(&x);
+}

tests/ui/compiletest-self-test/show-std-source.stderr

@@ -0,0 +1,42 @@
+error[E0107]: missing generics for enum `Foo`
+  --> $DIR/show-std-source.rs:12:10
+   |
+LL | fn f(x: &Foo) {
+   |          ^^^ expected 1 generic argument
+   |
+note: enum defined here, with 1 generic parameter: `T`
+  --> $DIR/show-std-source.rs:5:6
+   |
+LL | enum Foo<T> {
+   |      ^^^ -
+help: add missing generic argument
+   |
+LL | fn f(x: &Foo<T>) {
+   |             +++
+
+error[E0277]: can't compare `&isize` with `{integer}`
+  --> $DIR/show-std-source.rs:16:13
+   |
+LL |             assert_eq!(y, 2);
+   |             ^^^^^^^^^^^^^^^^ no implementation for `&isize == {integer}`
+   |
+   = help: the trait `PartialEq<{integer}>` is not implemented for `&isize`
+   = note: this error originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: consider dereferencing here
+  --> $SRC_DIR_REAL/core/src/macros/mod.rs:LL:COL
+   |
+LL |                 if !(**left_val == *right_val) {
+   |                      +
+
+error[E0559]: variant `Foo<_>::Bar` has no field named `x`
+  --> $DIR/show-std-source.rs:22:24
+   |
+LL |     let x = Foo::Bar { x: 1, y: 2 };
+   |                        ^ `Foo<_>::Bar` does not have this field
+   |
+   = note: available fields are: `v23`
+
+error: aborting due to 3 previous errors
+
+Some errors have detailed explanations: E0107, E0277, E0559.
+For more information about an error, try `rustc --explain E0107`.