5 files changed, 542 insertions, 16 deletions

diff --git a/crates/ra_hir_def/src/body.rs b/crates/ra_hir_def/src/body.rs
new file mode 100644
index 000000000..7447904ea
--- /dev/null
+++ b/crates/ra_hir_def/src/body.rs
@@ -0,0 +1,2 @@
+//! FIXME: write short doc here
+mod lower;
diff --git a/crates/ra_hir_def/src/body/lower.rs b/crates/ra_hir_def/src/body/lower.rs
new file mode 100644
index 000000000..1a144b1f9
--- /dev/null
+++ b/crates/ra_hir_def/src/body/lower.rs
@@ -0,0 +1,49 @@
+//! FIXME: write short doc here
+
+use ra_syntax::ast;
+
+use crate::expr::{ArithOp, BinaryOp, CmpOp, LogicOp, Ordering};
+
+impl From<ast::BinOp> for BinaryOp {
+    fn from(ast_op: ast::BinOp) -> Self {
+        match ast_op {
+            ast::BinOp::BooleanOr => BinaryOp::LogicOp(LogicOp::Or),
+            ast::BinOp::BooleanAnd => BinaryOp::LogicOp(LogicOp::And),
+            ast::BinOp::EqualityTest => BinaryOp::CmpOp(CmpOp::Eq { negated: false }),
+            ast::BinOp::NegatedEqualityTest => BinaryOp::CmpOp(CmpOp::Eq { negated: true }),
+            ast::BinOp::LesserEqualTest => {
+                BinaryOp::CmpOp(CmpOp::Ord { ordering: Ordering::Less, strict: false })
+            }
+            ast::BinOp::GreaterEqualTest => {
+                BinaryOp::CmpOp(CmpOp::Ord { ordering: Ordering::Greater, strict: false })
+            }
+            ast::BinOp::LesserTest => {
+                BinaryOp::CmpOp(CmpOp::Ord { ordering: Ordering::Less, strict: true })
+            }
+            ast::BinOp::GreaterTest => {
+                BinaryOp::CmpOp(CmpOp::Ord { ordering: Ordering::Greater, strict: true })
+            }
+            ast::BinOp::Addition => BinaryOp::ArithOp(ArithOp::Add),
+            ast::BinOp::Multiplication => BinaryOp::ArithOp(ArithOp::Mul),
+            ast::BinOp::Subtraction => BinaryOp::ArithOp(ArithOp::Sub),
+            ast::BinOp::Division => BinaryOp::ArithOp(ArithOp::Div),
+            ast::BinOp::Remainder => BinaryOp::ArithOp(ArithOp::Rem),
+            ast::BinOp::LeftShift => BinaryOp::ArithOp(ArithOp::Shl),
+            ast::BinOp::RightShift => BinaryOp::ArithOp(ArithOp::Shr),
+            ast::BinOp::BitwiseXor => BinaryOp::ArithOp(ArithOp::BitXor),
+            ast::BinOp::BitwiseOr => BinaryOp::ArithOp(ArithOp::BitOr),
+            ast::BinOp::BitwiseAnd => BinaryOp::ArithOp(ArithOp::BitAnd),
+            ast::BinOp::Assignment => BinaryOp::Assignment { op: None },
+            ast::BinOp::AddAssign => BinaryOp::Assignment { op: Some(ArithOp::Add) },
+            ast::BinOp::DivAssign => BinaryOp::Assignment { op: Some(ArithOp::Div) },
+            ast::BinOp::MulAssign => BinaryOp::Assignment { op: Some(ArithOp::Mul) },
+            ast::BinOp::RemAssign => BinaryOp::Assignment { op: Some(ArithOp::Rem) },
+            ast::BinOp::ShlAssign => BinaryOp::Assignment { op: Some(ArithOp::Shl) },
+            ast::BinOp::ShrAssign => BinaryOp::Assignment { op: Some(ArithOp::Shr) },
+            ast::BinOp::SubAssign => BinaryOp::Assignment { op: Some(ArithOp::Sub) },
+            ast::BinOp::BitOrAssign => BinaryOp::Assignment { op: Some(ArithOp::BitOr) },
+            ast::BinOp::BitAndAssign => BinaryOp::Assignment { op: Some(ArithOp::BitAnd) },
+            ast::BinOp::BitXorAssign => BinaryOp::Assignment { op: Some(ArithOp::BitXor) },
+        }
+    }
+}
diff --git a/crates/ra_hir_def/src/builtin_type.rs b/crates/ra_hir_def/src/builtin_type.rs
index 996e86fd9..5e8157144 100644
--- a/crates/ra_hir_def/src/builtin_type.rs
+++ b/crates/ra_hir_def/src/builtin_type.rs
@@ -56,22 +56,22 @@ impl BuiltinType {
         (name::BOOL, BuiltinType::Bool),
         (name::STR,  BuiltinType::Str ),
 
-        (name::ISIZE, BuiltinType::Int(BuiltinInt { signedness: Signedness::Signed,   bitness: IntBitness::Xsize })),
-        (name::I8,    BuiltinType::Int(BuiltinInt { signedness: Signedness::Signed,   bitness: IntBitness::X8    })),
-        (name::I16,   BuiltinType::Int(BuiltinInt { signedness: Signedness::Signed,   bitness: IntBitness::X16   })),
-        (name::I32,   BuiltinType::Int(BuiltinInt { signedness: Signedness::Signed,   bitness: IntBitness::X32   })),
-        (name::I64,   BuiltinType::Int(BuiltinInt { signedness: Signedness::Signed,   bitness: IntBitness::X64   })),
-        (name::I128,  BuiltinType::Int(BuiltinInt { signedness: Signedness::Signed,   bitness: IntBitness::X128  })),
-
-        (name::USIZE, BuiltinType::Int(BuiltinInt { signedness: Signedness::Unsigned, bitness: IntBitness::Xsize })),
-        (name::U8,    BuiltinType::Int(BuiltinInt { signedness: Signedness::Unsigned, bitness: IntBitness::X8    })),
-        (name::U16,   BuiltinType::Int(BuiltinInt { signedness: Signedness::Unsigned, bitness: IntBitness::X16   })),
-        (name::U32,   BuiltinType::Int(BuiltinInt { signedness: Signedness::Unsigned, bitness: IntBitness::X32   })),
-        (name::U64,   BuiltinType::Int(BuiltinInt { signedness: Signedness::Unsigned, bitness: IntBitness::X64   })),
-        (name::U128,  BuiltinType::Int(BuiltinInt { signedness: Signedness::Unsigned, bitness: IntBitness::X128  })),
-
-        (name::F32, BuiltinType::Float(BuiltinFloat { bitness: FloatBitness::X32 })),
-        (name::F64, BuiltinType::Float(BuiltinFloat { bitness: FloatBitness::X64 })),
+        (name::ISIZE, BuiltinType::Int(BuiltinInt::ISIZE)),
+        (name::I8,    BuiltinType::Int(BuiltinInt::I8)),
+        (name::I16,   BuiltinType::Int(BuiltinInt::I16)),
+        (name::I32,   BuiltinType::Int(BuiltinInt::I32)),
+        (name::I64,   BuiltinType::Int(BuiltinInt::I64)),
+        (name::I128,  BuiltinType::Int(BuiltinInt::I128)),
+
+        (name::USIZE, BuiltinType::Int(BuiltinInt::USIZE)),
+        (name::U8,    BuiltinType::Int(BuiltinInt::U8)),
+        (name::U16,   BuiltinType::Int(BuiltinInt::U16)),
+        (name::U32,   BuiltinType::Int(BuiltinInt::U32)),
+        (name::U64,   BuiltinType::Int(BuiltinInt::U64)),
+        (name::U128,  BuiltinType::Int(BuiltinInt::U128)),
+
+        (name::F32, BuiltinType::Float(BuiltinFloat::F32)),
+        (name::F64, BuiltinType::Float(BuiltinFloat::F64)),
     ];
 }
 
@@ -104,3 +104,57 @@ impl fmt::Display for BuiltinType {
         f.write_str(type_name)
     }
 }
+
+#[rustfmt::skip]
+impl BuiltinInt {
+    pub const ISIZE: BuiltinInt = BuiltinInt { signedness: Signedness::Signed, bitness: IntBitness::Xsize   };
+    pub const I8   : BuiltinInt = BuiltinInt { signedness: Signedness::Signed, bitness: IntBitness::X8      };
+    pub const I16  : BuiltinInt = BuiltinInt { signedness: Signedness::Signed, bitness: IntBitness::X16     };
+    pub const I32  : BuiltinInt = BuiltinInt { signedness: Signedness::Signed, bitness: IntBitness::X32     };
+    pub const I64  : BuiltinInt = BuiltinInt { signedness: Signedness::Signed, bitness: IntBitness::X64     };
+    pub const I128 : BuiltinInt = BuiltinInt { signedness: Signedness::Signed, bitness: IntBitness::X128    };
+
+    pub const USIZE: BuiltinInt = BuiltinInt { signedness: Signedness::Unsigned, bitness: IntBitness::Xsize };
+    pub const U8   : BuiltinInt = BuiltinInt { signedness: Signedness::Unsigned, bitness: IntBitness::X8    };
+    pub const U16  : BuiltinInt = BuiltinInt { signedness: Signedness::Unsigned, bitness: IntBitness::X16   };
+    pub const U32  : BuiltinInt = BuiltinInt { signedness: Signedness::Unsigned, bitness: IntBitness::X32   };
+    pub const U64  : BuiltinInt = BuiltinInt { signedness: Signedness::Unsigned, bitness: IntBitness::X64   };
+    pub const U128 : BuiltinInt = BuiltinInt { signedness: Signedness::Unsigned, bitness: IntBitness::X128  };
+
+
+    pub fn from_suffix(suffix: &str) -> Option<BuiltinInt> {
+        let res = match suffix {
+            "isize" => Self::ISIZE,
+            "i8"    => Self::I8,
+            "i16"   => Self::I16,
+            "i32"   => Self::I32,
+            "i64"   => Self::I64,
+            "i128"  => Self::I128,
+
+            "usize" => Self::USIZE,
+            "u8"    => Self::U8,
+            "u16"   => Self::U16,
+            "u32"   => Self::U32,
+            "u64"   => Self::U64,
+            "u128"  => Self::U128,
+
+            _ => return None,
+        };
+        Some(res)
+    }
+}
+
+#[rustfmt::skip]
+impl BuiltinFloat {
+    pub const F32: BuiltinFloat = BuiltinFloat { bitness: FloatBitness::X32 };
+    pub const F64: BuiltinFloat = BuiltinFloat { bitness: FloatBitness::X64 };
+
+    pub fn from_suffix(suffix: &str) -> Option<BuiltinFloat> {
+        let res = match suffix {
+            "f32" => BuiltinFloat::F32,
+            "f64" => BuiltinFloat::F64,
+            _ => return None,
+        };
+        Some(res)
+    }
+}
diff --git a/crates/ra_hir_def/src/expr.rs b/crates/ra_hir_def/src/expr.rs
new file mode 100644
index 000000000..12eb0da68
--- /dev/null
+++ b/crates/ra_hir_def/src/expr.rs
@@ -0,0 +1,419 @@
+//! This module describes hir-level representation of expressions.
+//!
+//! This representaion is:
+//!
+//! 1. Identity-based. Each expression has an `id`, so we can distinguish
+//!    between different `1` in `1 + 1`.
+//! 2. Independent of syntax. Though syntactic provenance information can be
+//!    attached separately via id-based side map.
+//! 3. Unresolved. Paths are stored as sequences of names, and not as defs the
+//!    names refer to.
+//! 4. Desugared. There's no `if let`.
+
+use hir_expand::name::Name;
+use ra_arena::{impl_arena_id, RawId};
+
+use crate::{
+    builtin_type::{BuiltinFloat, BuiltinInt},
+    path::{GenericArgs, Path},
+    type_ref::{Mutability, TypeRef},
+};
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct ExprId(RawId);
+impl_arena_id!(ExprId);
+
+impl ExprId {
+    pub fn dummy() -> ExprId {
+        ExprId((!0).into())
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct PatId(RawId);
+impl_arena_id!(PatId);
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub enum Literal {
+    String(String),
+    ByteString(Vec<u8>),
+    Char(char),
+    Bool(bool),
+    Int(u64, Option<BuiltinInt>),
+    Float(u64, Option<BuiltinFloat>), // FIXME: f64 is not Eq
+}
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub enum Expr {
+    /// This is produced if syntax tree does not have a required expression piece.
+    Missing,
+    Path(Path),
+    If {
+        condition: ExprId,
+        then_branch: ExprId,
+        else_branch: Option<ExprId>,
+    },
+    Block {
+        statements: Vec<Statement>,
+        tail: Option<ExprId>,
+    },
+    Loop {
+        body: ExprId,
+    },
+    While {
+        condition: ExprId,
+        body: ExprId,
+    },
+    For {
+        iterable: ExprId,
+        pat: PatId,
+        body: ExprId,
+    },
+    Call {
+        callee: ExprId,
+        args: Vec<ExprId>,
+    },
+    MethodCall {
+        receiver: ExprId,
+        method_name: Name,
+        args: Vec<ExprId>,
+        generic_args: Option<GenericArgs>,
+    },
+    Match {
+        expr: ExprId,
+        arms: Vec<MatchArm>,
+    },
+    Continue,
+    Break {
+        expr: Option<ExprId>,
+    },
+    Return {
+        expr: Option<ExprId>,
+    },
+    RecordLit {
+        path: Option<Path>,
+        fields: Vec<RecordLitField>,
+        spread: Option<ExprId>,
+    },
+    Field {
+        expr: ExprId,
+        name: Name,
+    },
+    Await {
+        expr: ExprId,
+    },
+    Try {
+        expr: ExprId,
+    },
+    TryBlock {
+        body: ExprId,
+    },
+    Cast {
+        expr: ExprId,
+        type_ref: TypeRef,
+    },
+    Ref {
+        expr: ExprId,
+        mutability: Mutability,
+    },
+    Box {
+        expr: ExprId,
+    },
+    UnaryOp {
+        expr: ExprId,
+        op: UnaryOp,
+    },
+    BinaryOp {
+        lhs: ExprId,
+        rhs: ExprId,
+        op: Option<BinaryOp>,
+    },
+    Index {
+        base: ExprId,
+        index: ExprId,
+    },
+    Lambda {
+        args: Vec<PatId>,
+        arg_types: Vec<Option<TypeRef>>,
+        body: ExprId,
+    },
+    Tuple {
+        exprs: Vec<ExprId>,
+    },
+    Array(Array),
+    Literal(Literal),
+}
+
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
+pub enum BinaryOp {
+    LogicOp(LogicOp),
+    ArithOp(ArithOp),
+    CmpOp(CmpOp),
+    Assignment { op: Option<ArithOp> },
+}
+
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
+pub enum LogicOp {
+    And,
+    Or,
+}
+
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
+pub enum CmpOp {
+    Eq { negated: bool },
+    Ord { ordering: Ordering, strict: bool },
+}
+
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
+pub enum Ordering {
+    Less,
+    Greater,
+}
+
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
+pub enum ArithOp {
+    Add,
+    Mul,
+    Sub,
+    Div,
+    Rem,
+    Shl,
+    Shr,
+    BitXor,
+    BitOr,
+    BitAnd,
+}
+
+pub use ra_syntax::ast::PrefixOp as UnaryOp;
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub enum Array {
+    ElementList(Vec<ExprId>),
+    Repeat { initializer: ExprId, repeat: ExprId },
+}
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct MatchArm {
+    pub pats: Vec<PatId>,
+    pub guard: Option<ExprId>,
+    pub expr: ExprId,
+}
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct RecordLitField {
+    pub name: Name,
+    pub expr: ExprId,
+}
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub enum Statement {
+    Let { pat: PatId, type_ref: Option<TypeRef>, initializer: Option<ExprId> },
+    Expr(ExprId),
+}
+
+impl Expr {
+    pub fn walk_child_exprs(&self, mut f: impl FnMut(ExprId)) {
+        match self {
+            Expr::Missing => {}
+            Expr::Path(_) => {}
+            Expr::If { condition, then_branch, else_branch } => {
+                f(*condition);
+                f(*then_branch);
+                if let Some(else_branch) = else_branch {
+                    f(*else_branch);
+                }
+            }
+            Expr::Block { statements, tail } => {
+                for stmt in statements {
+                    match stmt {
+                        Statement::Let { initializer, .. } => {
+                            if let Some(expr) = initializer {
+                                f(*expr);
+                            }
+                        }
+                        Statement::Expr(e) => f(*e),
+                    }
+                }
+                if let Some(expr) = tail {
+                    f(*expr);
+                }
+            }
+            Expr::TryBlock { body } => f(*body),
+            Expr::Loop { body } => f(*body),
+            Expr::While { condition, body } => {
+                f(*condition);
+                f(*body);
+            }
+            Expr::For { iterable, body, .. } => {
+                f(*iterable);
+                f(*body);
+            }
+            Expr::Call { callee, args } => {
+                f(*callee);
+                for arg in args {
+                    f(*arg);
+                }
+            }
+            Expr::MethodCall { receiver, args, .. } => {
+                f(*receiver);
+                for arg in args {
+                    f(*arg);
+                }
+            }
+            Expr::Match { expr, arms } => {
+                f(*expr);
+                for arm in arms {
+                    f(arm.expr);
+                }
+            }
+            Expr::Continue => {}
+            Expr::Break { expr } | Expr::Return { expr } => {
+                if let Some(expr) = expr {
+                    f(*expr);
+                }
+            }
+            Expr::RecordLit { fields, spread, .. } => {
+                for field in fields {
+                    f(field.expr);
+                }
+                if let Some(expr) = spread {
+                    f(*expr);
+                }
+            }
+            Expr::Lambda { body, .. } => {
+                f(*body);
+            }
+            Expr::BinaryOp { lhs, rhs, .. } => {
+                f(*lhs);
+                f(*rhs);
+            }
+            Expr::Index { base, index } => {
+                f(*base);
+                f(*index);
+            }
+            Expr::Field { expr, .. }
+            | Expr::Await { expr }
+            | Expr::Try { expr }
+            | Expr::Cast { expr, .. }
+            | Expr::Ref { expr, .. }
+            | Expr::UnaryOp { expr, .. }
+            | Expr::Box { expr } => {
+                f(*expr);
+            }
+            Expr::Tuple { exprs } => {
+                for expr in exprs {
+                    f(*expr);
+                }
+            }
+            Expr::Array(a) => match a {
+                Array::ElementList(exprs) => {
+                    for expr in exprs {
+                        f(*expr);
+                    }
+                }
+                Array::Repeat { initializer, repeat } => {
+                    f(*initializer);
+                    f(*repeat)
+                }
+            },
+            Expr::Literal(_) => {}
+        }
+    }
+}
+
+/// Explicit binding annotations given in the HIR for a binding. Note
+/// that this is not the final binding *mode* that we infer after type
+/// inference.
+#[derive(Clone, PartialEq, Eq, Debug, Copy)]
+pub enum BindingAnnotation {
+    /// No binding annotation given: this means that the final binding mode
+    /// will depend on whether we have skipped through a `&` reference
+    /// when matching. For example, the `x` in `Some(x)` will have binding
+    /// mode `None`; if you do `let Some(x) = &Some(22)`, it will
+    /// ultimately be inferred to be by-reference.
+    Unannotated,
+
+    /// Annotated with `mut x` -- could be either ref or not, similar to `None`.
+    Mutable,
+
+    /// Annotated as `ref`, like `ref x`
+    Ref,
+
+    /// Annotated as `ref mut x`.
+    RefMut,
+}
+
+impl BindingAnnotation {
+    pub fn new(is_mutable: bool, is_ref: bool) -> Self {
+        match (is_mutable, is_ref) {
+            (true, true) => BindingAnnotation::RefMut,
+            (false, true) => BindingAnnotation::Ref,
+            (true, false) => BindingAnnotation::Mutable,
+            (false, false) => BindingAnnotation::Unannotated,
+        }
+    }
+}
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct RecordFieldPat {
+    pub name: Name,
+    pub pat: PatId,
+}
+
+/// Close relative to rustc's hir::PatKind
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub enum Pat {
+    Missing,
+    Wild,
+    Tuple(Vec<PatId>),
+    Record {
+        path: Option<Path>,
+        args: Vec<RecordFieldPat>,
+        // FIXME: 'ellipsis' option
+    },
+    Range {
+        start: ExprId,
+        end: ExprId,
+    },
+    Slice {
+        prefix: Vec<PatId>,
+        rest: Option<PatId>,
+        suffix: Vec<PatId>,
+    },
+    Path(Path),
+    Lit(ExprId),
+    Bind {
+        mode: BindingAnnotation,
+        name: Name,
+        subpat: Option<PatId>,
+    },
+    TupleStruct {
+        path: Option<Path>,
+        args: Vec<PatId>,
+    },
+    Ref {
+        pat: PatId,
+        mutability: Mutability,
+    },
+}
+
+impl Pat {
+    pub fn walk_child_pats(&self, mut f: impl FnMut(PatId)) {
+        match self {
+            Pat::Range { .. } | Pat::Lit(..) | Pat::Path(..) | Pat::Wild | Pat::Missing => {}
+            Pat::Bind { subpat, .. } => {
+                subpat.iter().copied().for_each(f);
+            }
+            Pat::Tuple(args) | Pat::TupleStruct { args, .. } => {
+                args.iter().copied().for_each(f);
+            }
+            Pat::Ref { pat, .. } => f(*pat),
+            Pat::Slice { prefix, rest, suffix } => {
+                let total_iter = prefix.iter().chain(rest.iter()).chain(suffix.iter());
+                total_iter.copied().for_each(f);
+            }
+            Pat::Record { args, .. } => {
+                args.iter().map(|f| f.pat).for_each(f);
+            }
+        }
+    }
+}
diff --git a/crates/ra_hir_def/src/lib.rs b/crates/ra_hir_def/src/lib.rs
index 239317efe..4a758bb83 100644
--- a/crates/ra_hir_def/src/lib.rs
+++ b/crates/ra_hir_def/src/lib.rs
@@ -14,6 +14,8 @@ pub mod type_ref;
 pub mod builtin_type;
 pub mod adt;
 pub mod diagnostics;
+pub mod expr;
+pub mod body;
 
 #[cfg(test)]
 mod test_db;