Rollup merge of rust-lang#37124 - nikomatsakis:incr-comp-benchmark, r=michaelwoerister

add test case for changing private methods

The goal of this test case is to ensure we are getting the reuse we expect. This targets a particular change where we modify the body of a private inherent method defined on a struct, and looks at different ways we can use that struct.

It checks for when type-checking would be needed as well as the actual reuse achieved.

cc rust-lang#37121
r? @michaelwoerister

Author: eddyb

src/test/incremental/change_private_impl_method/struct_point.rs

@@ -0,0 +1,114 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Test where we change the body of a private method in an impl.
+// We then test what sort of functions must be rebuilt as a result.
+
+// revisions:rpass1 rpass2
+// compile-flags: -Z query-dep-graph
+
+#![feature(rustc_attrs)]
+#![feature(stmt_expr_attributes)]
+#![allow(dead_code)]
+
+#![rustc_partition_translated(module="struct_point-point", cfg="rpass2")]
+
+// FIXME(#37121) -- the following two modules *should* be reused but are not
+#![rustc_partition_translated(module="struct_point-fn_calls_methods_in_same_impl", cfg="rpass2")]
+#![rustc_partition_translated(module="struct_point-fn_calls_methods_in_another_impl", cfg="rpass2")]
+#![rustc_partition_reused(module="struct_point-fn_make_struct", cfg="rpass2")]
+#![rustc_partition_reused(module="struct_point-fn_read_field", cfg="rpass2")]
+#![rustc_partition_reused(module="struct_point-fn_write_field", cfg="rpass2")]
+
+mod point {
+    pub struct Point {
+        pub x: f32,
+        pub y: f32,
+    }
+
+    impl Point {
+        fn distance_squared(&self) -> f32 {
+            #[cfg(rpass1)]
+            return self.x + self.y;
+
+            #[cfg(rpass2)]
+            return self.x * self.x + self.y * self.y;
+        }
+
+        pub fn distance_from_origin(&self) -> f32 {
+            self.distance_squared().sqrt()
+        }
+    }
+
+    impl Point {
+        pub fn translate(&mut self, x: f32, y: f32) {
+            self.x += x;
+            self.y += y;
+        }
+    }
+
+}
+
+/// A fn item that calls (public) methods on `Point` from the same impl which changed
+mod fn_calls_methods_in_same_impl {
+    use point::Point;
+
+    // FIXME(#37121) -- we should not need to typeck this again
+    #[rustc_dirty(label="TypeckItemBody", cfg="rpass2")]
+    pub fn check() {
+        let x = Point { x: 2.0, y: 2.0 };
+        x.distance_from_origin();
+    }
+}
+
+/// A fn item that calls (public) methods on `Point` from another impl
+mod fn_calls_methods_in_another_impl {
+    use point::Point;
+
+    // FIXME(#37121) -- we should not need to typeck this again
+    #[rustc_dirty(label="TypeckItemBody", cfg="rpass2")]
+    pub fn check() {
+        let mut x = Point { x: 2.0, y: 2.0 };
+        x.translate(3.0, 3.0);
+    }
+}
+
+/// A fn item that makes an instance of `Point` but does not invoke methods
+mod fn_make_struct {
+    use point::Point;
+
+    #[rustc_clean(label="TypeckItemBody", cfg="rpass2")]
+    pub fn make_origin() -> Point {
+        Point { x: 2.0, y: 2.0 }
+    }
+}
+
+/// A fn item that reads fields from `Point` but does not invoke methods
+mod fn_read_field {
+    use point::Point;
+
+    #[rustc_clean(label="TypeckItemBody", cfg="rpass2")]
+    pub fn get_x(p: Point) -> f32 {
+        p.x
+    }
+}
+
+/// A fn item that writes to a field of `Point` but does not invoke methods
+mod fn_write_field {
+    use point::Point;
+
+    #[rustc_clean(label="TypeckItemBody", cfg="rpass2")]
+    pub fn inc_x(p: &mut Point) {
+        p.x += 1.0;
+    }
+}
+
+fn main() {
+}