Detect diff markers in the parser

Partly address #32059.

12 files changed, 157 insertions, 0 deletions

diff --git a/src/test/ui/parser/diff-markers/fn-arg.rs b/src/test/ui/parser/diff-markers/fn-arg.rs
new file mode 100644
index 00000000000..86c355628ab
--- /dev/null
+++ b/src/test/ui/parser/diff-markers/fn-arg.rs
@@ -0,0 +1,16 @@
+trait T {
+    fn foo(
+<<<<<<< HEAD //~ ERROR encountered diff marker
+        x: u8,
+=======
+        x: i8,
+>>>>>>> branch
+    ) {}
+}
+
+struct S;
+impl T for S {}
+
+fn main() {
+    S::foo(42);
+}
diff --git a/src/test/ui/parser/diff-markers/fn-arg.stderr b/src/test/ui/parser/diff-markers/fn-arg.stderr
new file mode 100644
index 00000000000..4a816ff75bc
--- /dev/null
+++ b/src/test/ui/parser/diff-markers/fn-arg.stderr
@@ -0,0 +1,14 @@
+error: encountered diff marker
+  --> $DIR/fn-arg.rs:3:1
+   |
+LL | <<<<<<< HEAD
+   | ^^^^^^^ start
+LL |         x: u8,
+LL | =======
+   | ^^^^^^^ middle
+LL |         x: i8,
+LL | >>>>>>> branch
+   | ^^^^^^^ end
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/parser/diff-markers/item-with-attr.rs b/src/test/ui/parser/diff-markers/item-with-attr.rs
new file mode 100644
index 00000000000..985907c08b2
--- /dev/null
+++ b/src/test/ui/parser/diff-markers/item-with-attr.rs
@@ -0,0 +1,10 @@
+#[attribute]
+<<<<<<< HEAD //~ ERROR encountered diff marker
+fn foo() {}
+=======
+fn bar() {}
+>>>>>>> branch
+
+fn main() {
+    foo();
+}
diff --git a/src/test/ui/parser/diff-markers/item-with-attr.stderr b/src/test/ui/parser/diff-markers/item-with-attr.stderr
new file mode 100644
index 00000000000..4fcb782846e
--- /dev/null
+++ b/src/test/ui/parser/diff-markers/item-with-attr.stderr
@@ -0,0 +1,14 @@
+error: encountered diff marker
+  --> $DIR/item-with-attr.rs:2:1
+   |
+LL | <<<<<<< HEAD
+   | ^^^^^^^ start
+LL | fn foo() {}
+LL | =======
+   | ^^^^^^^ middle
+LL | fn bar() {}
+LL | >>>>>>> branch
+   | ^^^^^^^ end
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/parser/diff-markers/item.rs b/src/test/ui/parser/diff-markers/item.rs
new file mode 100644
index 00000000000..4ed36b7b42b
--- /dev/null
+++ b/src/test/ui/parser/diff-markers/item.rs
@@ -0,0 +1,9 @@
+<<<<<<< HEAD //~ ERROR encountered diff marker
+fn foo() {}
+=======
+fn bar() {}
+>>>>>>> branch
+
+fn main() {
+    foo();
+}
diff --git a/src/test/ui/parser/diff-markers/item.stderr b/src/test/ui/parser/diff-markers/item.stderr
new file mode 100644
index 00000000000..7c81f0fafa6
--- /dev/null
+++ b/src/test/ui/parser/diff-markers/item.stderr
@@ -0,0 +1,14 @@
+error: encountered diff marker
+  --> $DIR/item.rs:1:1
+   |
+LL | <<<<<<< HEAD
+   | ^^^^^^^ start
+LL | fn foo() {}
+LL | =======
+   | ^^^^^^^ middle
+LL | fn bar() {}
+LL | >>>>>>> branch
+   | ^^^^^^^ end
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/parser/diff-markers/statement.rs b/src/test/ui/parser/diff-markers/statement.rs
new file mode 100644
index 00000000000..e55d16d3bbb
--- /dev/null
+++ b/src/test/ui/parser/diff-markers/statement.rs
@@ -0,0 +1,15 @@
+trait T {
+    fn foo() {}
+    fn bar() {}
+}
+
+struct S;
+impl T for S {}
+
+fn main() {
+<<<<<<< HEAD //~ ERROR encountered diff marker
+    S::foo();
+=======
+    S::bar();
+>>>>>>> branch
+}
diff --git a/src/test/ui/parser/diff-markers/statement.stderr b/src/test/ui/parser/diff-markers/statement.stderr
new file mode 100644
index 00000000000..4c821c02f0d
--- /dev/null
+++ b/src/test/ui/parser/diff-markers/statement.stderr
@@ -0,0 +1,14 @@
+error: encountered diff marker
+  --> $DIR/statement.rs:10:1
+   |
+LL | <<<<<<< HEAD
+   | ^^^^^^^ start
+LL |     S::foo();
+LL | =======
+   | ^^^^^^^ middle
+LL |     S::bar();
+LL | >>>>>>> branch
+   | ^^^^^^^ end
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/parser/diff-markers/trait-item.rs b/src/test/ui/parser/diff-markers/trait-item.rs
new file mode 100644
index 00000000000..3227c8212c9
--- /dev/null
+++ b/src/test/ui/parser/diff-markers/trait-item.rs
@@ -0,0 +1,14 @@
+trait T {
+<<<<<<< HEAD //~ ERROR encountered diff marker
+    fn foo() {}
+=======
+    fn bar() {}
+>>>>>>> branch
+}
+
+struct S;
+impl T for S {}
+
+fn main() {
+    S::foo();
+}
diff --git a/src/test/ui/parser/diff-markers/trait-item.stderr b/src/test/ui/parser/diff-markers/trait-item.stderr
new file mode 100644
index 00000000000..8e18d5db7c7
--- /dev/null
+++ b/src/test/ui/parser/diff-markers/trait-item.stderr
@@ -0,0 +1,14 @@
+error: encountered diff marker
+  --> $DIR/trait-item.rs:2:1
+   |
+LL | <<<<<<< HEAD
+   | ^^^^^^^ start
+LL |     fn foo() {}
+LL | =======
+   | ^^^^^^^ middle
+LL |     fn bar() {}
+LL | >>>>>>> branch
+   | ^^^^^^^ end
+
+error: aborting due to previous error
+
diff --git a/src/test/ui/parser/diff-markers/use-statement.rs b/src/test/ui/parser/diff-markers/use-statement.rs
new file mode 100644
index 00000000000..6306243a514
--- /dev/null
+++ b/src/test/ui/parser/diff-markers/use-statement.rs
@@ -0,0 +1,9 @@
+use foo::{
+<<<<<<< HEAD //~ ERROR encountered diff marker
+    bar,
+=======
+    baz,
+>>>>>>> branch
+};
+
+fn main() {}
diff --git a/src/test/ui/parser/diff-markers/use-statement.stderr b/src/test/ui/parser/diff-markers/use-statement.stderr
new file mode 100644
index 00000000000..818c90aa59b
--- /dev/null
+++ b/src/test/ui/parser/diff-markers/use-statement.stderr
@@ -0,0 +1,14 @@
+error: encountered diff marker
+  --> $DIR/use-statement.rs:2:1
+   |
+LL | <<<<<<< HEAD
+   | ^^^^^^^ start
+LL |     bar,
+LL | =======
+   | ^^^^^^^ middle
+LL |     baz,
+LL | >>>>>>> branch
+   | ^^^^^^^ end
+
+error: aborting due to previous error
+