Add need-mut and unused-mut diagnostics

crates/hir-ty/src/mir.rs

@@ -7,17 +7,19 @@ use crate::{
 };
 use chalk_ir::Mutability;
 use hir_def::{
-    expr::{Expr, Ordering},
+    expr::{BindingId, Expr, ExprId, Ordering, PatId},
     DefWithBodyId, FieldId, UnionId, VariantId,
 };
-use la_arena::{Arena, Idx, RawIdx};
+use la_arena::{Arena, ArenaMap, Idx, RawIdx};
 
 mod eval;
 mod lower;
+pub mod borrowck;
 
 pub use eval::{interpret_mir, pad16, Evaluator, MirEvalError};
 pub use lower::{lower_to_mir, mir_body_query, mir_body_recover, MirLowerError};
 use smallvec::{smallvec, SmallVec};
+use stdx::impl_from;
 
 use super::consteval::{intern_const_scalar, try_const_usize};
 
@@ -181,6 +183,11 @@ impl SwitchTargets {
         iter::zip(&self.values, &self.targets).map(|(x, y)| (*x, *y))
     }
 
+    /// Returns a slice with all possible jump targets (including the fallback target).
+    pub fn all_targets(&self) -> &[BasicBlockId] {
+        &self.targets
+    }
+
     /// Finds the `BasicBlock` to which this `SwitchInt` will branch given the
     /// specific value. This cannot fail, as it'll return the `otherwise`
     /// branch if there's not a specific match for the value.
@@ -758,7 +765,7 @@ pub enum Rvalue {
 }
 
 #[derive(Debug, PartialEq, Eq, Clone)]
-pub enum Statement {
+pub enum StatementKind {
     Assign(Place, Rvalue),
     //FakeRead(Box<(FakeReadCause, Place)>),
     //SetDiscriminant {
@@ -773,6 +780,17 @@ pub enum Statement {
     //Intrinsic(Box<NonDivergingIntrinsic>),
     Nop,
 }
+impl StatementKind {
+    fn with_span(self, span: MirSpan) -> Statement {
+        Statement { kind: self, span }
+    }
+}
+
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub struct Statement {
+    pub kind: StatementKind,
+    pub span: MirSpan,
+}
 
 #[derive(Debug, Default, PartialEq, Eq)]
 pub struct BasicBlock {
@@ -803,6 +821,7 @@ pub struct MirBody {
     pub start_block: BasicBlockId,
     pub owner: DefWithBodyId,
     pub arg_count: usize,
+    pub binding_locals: ArenaMap<BindingId, LocalId>,
 }
 
 impl MirBody {}
@@ -810,3 +829,12 @@ impl MirBody {}
 fn const_as_usize(c: &Const) -> usize {
     try_const_usize(c).unwrap() as usize
 }
+
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+pub enum MirSpan {
+    ExprId(ExprId),
+    PatId(PatId),
+    Unknown,
+}
+
+impl_from!(ExprId, PatId for MirSpan);