Merge #576

576: Beginnings of generics r=matklad a=flodiebold

This implements the beginnings of the generics infrastructure; generic parameters for structs work and are correctly substituted in fields. Functions and methods aren't handled at all yet (as the tests show).

The name resolution in `ty` really needs refactoring now, I hope to do that next ;)

Co-authored-by: Florian Diebold <[email protected]>

6 files changed, 178 insertions, 3 deletions

diff --git a/crates/ra_hir/src/ty/method_resolution.rs b/crates/ra_hir/src/ty/method_resolution.rs
index b221bd142..9f65c5fe1 100644
--- a/crates/ra_hir/src/ty/method_resolution.rs
+++ b/crates/ra_hir/src/ty/method_resolution.rs
@@ -8,7 +8,11 @@ use rustc_hash::FxHashMap;
 
 use ra_db::SourceRootId;
 
-use crate::{HirDatabase, DefId, module_tree::ModuleId, Module, Crate, Name, Function, impl_block::{ImplId, ImplBlock, ImplItem}};
+use crate::{
+    HirDatabase, DefId, module_tree::ModuleId, Module, Crate, Name, Function,
+    impl_block::{ImplId, ImplBlock, ImplItem},
+    generics::GenericParams
+};
 use super::Ty;
 
 /// This is used as a key for indexing impls.
@@ -64,8 +68,15 @@ impl CrateImplBlocks {
             if let Some(_target_trait) = impl_data.target_trait() {
                 // ignore for now
             } else {
-                let target_ty =
-                    Ty::from_hir(db, &module, Some(&impl_block), impl_data.target_type());
+                // TODO provide generics of impl
+                let generics = GenericParams::default();
+                let target_ty = Ty::from_hir(
+                    db,
+                    &module,
+                    Some(&impl_block),
+                    &generics,
+                    impl_data.target_type(),
+                );
                 if let Some(target_ty_fp) = TyFingerprint::for_impl(&target_ty) {
                     self.impls
                         .entry(target_ty_fp)
diff --git a/crates/ra_hir/src/ty/tests.rs b/crates/ra_hir/src/ty/tests.rs
index fc4054159..06e32df59 100644
--- a/crates/ra_hir/src/ty/tests.rs
+++ b/crates/ra_hir/src/ty/tests.rs
@@ -418,6 +418,95 @@ fn test() {
     );
 }
 
+#[test]
+fn infer_struct_generics() {
+    check_inference(
+        r#"
+struct A<T> {
+    x: T,
+}
+
+fn test(a1: A<u32>, i: i32) {
+    a1.x;
+    let a2 = A { x: i };
+    a2.x;
+    let a3 = A::<i128> { x: 1 };
+    a3.x;
+}
+"#,
+        "struct_generics.txt",
+    );
+}
+
+#[test]
+fn infer_generics_in_patterns() {
+    check_inference(
+        r#"
+struct A<T> {
+    x: T,
+}
+
+enum Option<T> {
+    Some(T),
+    None,
+}
+
+fn test(a1: A<u32>, o: Option<u64>) {
+    let A { x: x2 } = a1;
+    let A::<i64> { x: x3 } = A { x: 1 };
+    match o {
+        Option::Some(t) => t,
+        _ => 1,
+    };
+}
+"#,
+        "generics_in_patterns.txt",
+    );
+}
+
+#[test]
+fn infer_function_generics() {
+    check_inference(
+        r#"
+fn id<T>(t: T) -> T { t }
+
+fn test() {
+    id(1u32);
+    id::<i128>(1);
+    let x: u64 = id(1);
+}
+"#,
+        "function_generics.txt",
+    );
+}
+
+#[test]
+fn infer_generic_chain() {
+    check_inference(
+        r#"
+struct A<T> {
+    x: T,
+}
+impl<T2> A<T2> {
+    fn x(self) -> T2 {
+        self.x
+    }
+}
+fn id<T>(t: T) -> T { t }
+
+fn test() -> i128 {
+     let x = 1;
+     let y = id(x);
+     let a = A { x: id(y) };
+     let z = id(a.x);
+     let b = A { x: z };
+     b.x()
+}
+"#,
+        "generic_chain.txt",
+    );
+}
+
 fn infer(content: &str) -> String {
     let (db, _, file_id) = MockDatabase::with_single_file(content);
     let source_file = db.source_file(file_id);
diff --git a/crates/ra_hir/src/ty/tests/data/function_generics.txt b/crates/ra_hir/src/ty/tests/data/function_generics.txt
new file mode 100644
index 000000000..e44d26cfd
--- /dev/null
+++ b/crates/ra_hir/src/ty/tests/data/function_generics.txt
@@ -0,0 +1,14 @@
+[10; 11) 't': [unknown]
+[21; 26) '{ t }': [unknown]
+[23; 24) 't': [unknown]
+[38; 98) '{     ...(1); }': ()
+[44; 46) 'id': fn(T) -> T
+[44; 52) 'id(1u32)': T
+[47; 51) '1u32': u32
+[58; 68) 'id::<i128>': fn(T) -> T
+[58; 71) 'id::<i128>(1)': T
+[69; 70) '1': T
+[81; 82) 'x': T
+[90; 92) 'id': fn(T) -> T
+[90; 95) 'id(1)': T
+[93; 94) '1': T
diff --git a/crates/ra_hir/src/ty/tests/data/generic_chain.txt b/crates/ra_hir/src/ty/tests/data/generic_chain.txt
new file mode 100644
index 000000000..568e00846
--- /dev/null
+++ b/crates/ra_hir/src/ty/tests/data/generic_chain.txt
@@ -0,0 +1,29 @@
+[53; 57) 'self': A<[unknown]>
+[65; 87) '{     ...     }': [unknown]
+[75; 79) 'self': A<[unknown]>
+[75; 81) 'self.x': [unknown]
+[99; 100) 't': [unknown]
+[110; 115) '{ t }': [unknown]
+[112; 113) 't': [unknown]
+[135; 261) '{     ....x() }': i128
+[146; 147) 'x': T
+[150; 151) '1': T
+[162; 163) 'y': T
+[166; 168) 'id': fn(T) -> T
+[166; 171) 'id(x)': T
+[169; 170) 'x': T
+[182; 183) 'a': A<T>
+[186; 200) 'A { x: id(y) }': A<T>
+[193; 195) 'id': fn(T) -> T
+[193; 198) 'id(y)': T
+[196; 197) 'y': T
+[211; 212) 'z': T
+[215; 217) 'id': fn(T) -> T
+[215; 222) 'id(a.x)': T
+[218; 219) 'a': A<T>
+[218; 221) 'a.x': T
+[233; 234) 'b': A<T>
+[237; 247) 'A { x: z }': A<T>
+[244; 245) 'z': T
+[254; 255) 'b': A<T>
+[254; 259) 'b.x()': i128
diff --git a/crates/ra_hir/src/ty/tests/data/generics_in_patterns.txt b/crates/ra_hir/src/ty/tests/data/generics_in_patterns.txt
new file mode 100644
index 000000000..1b01ef19e
--- /dev/null
+++ b/crates/ra_hir/src/ty/tests/data/generics_in_patterns.txt
@@ -0,0 +1,17 @@
+[79; 81) 'a1': A<u32>
+[91; 92) 'o': Option<u64>
+[107; 244) '{     ...  }; }': ()
+[117; 128) 'A { x: x2 }': A<u32>
+[124; 126) 'x2': u32
+[131; 133) 'a1': A<u32>
+[143; 161) 'A::<i6...: x3 }': A<i64>
+[157; 159) 'x3': i64
+[164; 174) 'A { x: 1 }': A<i64>
+[171; 172) '1': i64
+[180; 241) 'match ...     }': u64
+[186; 187) 'o': Option<u64>
+[198; 213) 'Option::Some(t)': Option<u64>
+[211; 212) 't': u64
+[217; 218) 't': u64
+[228; 229) '_': Option<u64>
+[233; 234) '1': u64
diff --git a/crates/ra_hir/src/ty/tests/data/struct_generics.txt b/crates/ra_hir/src/ty/tests/data/struct_generics.txt
new file mode 100644
index 000000000..1024a39a9
--- /dev/null
+++ b/crates/ra_hir/src/ty/tests/data/struct_generics.txt
@@ -0,0 +1,15 @@
+[36; 38) 'a1': A<u32>
+[48; 49) 'i': i32
+[56; 147) '{     ...3.x; }': ()
+[62; 64) 'a1': A<u32>
+[62; 66) 'a1.x': u32
+[76; 78) 'a2': A<i32>
+[81; 91) 'A { x: i }': A<i32>
+[88; 89) 'i': i32
+[97; 99) 'a2': A<i32>
+[97; 101) 'a2.x': i32
+[111; 113) 'a3': A<i128>
+[116; 134) 'A::<i1...x: 1 }': A<i128>
+[131; 132) '1': i128
+[140; 142) 'a3': A<i128>
+[140; 144) 'a3.x': i128