Module rustc_middle::mir

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MIR datatypes and passes. See the rustc dev guide for more info.




  • A node in the MIR control-flow graph.
  • Data for a basic block, including a list of its statements.
  • BlockTailInfo is attached to the LocalDecl for temporaries created during evaluation of expressions in a block tail expression; that is, a block like { STMT_1; STMT_2; EXPR }.
  • The lowered representation of a single function.
  • Indicates an outlives-constraint between a type or between two free regions declared on the closure.
  • Represents a ty::Ty for use in ClosureOutlivesSubject.
  • After we borrow check a closure, we are left with various requirements that we have inferred between the free regions that appear in the closure’s signature or on its field types. These requirements are then verified and proved by the closure’s creating function. This struct encodes those requirements.
  • Evaluated Constants Represents the result of const evaluation via the eval_to_allocation query. Not to be confused with ConstAllocation, which directly refers to the underlying data! Here we indirect via an AllocId.
  • The result of the mir_const_qualif query.
  • Additional information carried by a MIR body when it is lowered from a coroutine. This information is modified as it is lowered during the StateTransform MIR pass, so not all fields will be active at a given time. For example, the yield_ty is taken out of the field after yields are turned into returns, and the coroutine_drop body is only populated after the state transform pass.
  • The layout of coroutine state.
  • Summarizes coverage IDs inserted by the InstrumentCoverage MIR pass (for compiler option -Cinstrument-coverage), after MIR optimizations have had a chance to potentially remove some of them.
  • The constituent parts of a mir constant of kind ADT or array.
  • A MIR local.
  • Location represents the position of the start of the statement; or, if statement_index equals the number of statements, then the start of the terminator.
  • Where a specific mir::Body comes from.
  • Places roughly correspond to a “location in memory.” Places in MIR are the same mathematical object as places in Rust. This of course means that what exactly they are is undecided and part of the Rust memory model. However, they will likely contain at least the following pieces of information in some form:
  • Grouped information about the source code origin of a MIR entity. Intended to be inspected by diagnostics and debuginfo. Most passes can work with it as a whole, within a single function.
  • A statement in a basic block, including information about its source code.
  • An unevaluated (potentially generic) constant used in MIR.
  • Encodes the effect of a user-supplied type annotation on the subcomponents of a pattern. The effect is determined by applying the given list of projections to some underlying base type. Often, the projection element list projs is empty, in which case this directly encodes a type in base. But in the case of complex patterns with subpatterns and bindings, we want to apply only a part of the type to a variable, in which case the projs vector is used.
  • A collection of projections into user types.
  • Debug information pertaining to a user variable.




  • A streamlined trait that you can implement to create a pass; the pass will be named after the type, and it will consist of a main loop that goes over each available MIR and applies run_pass.


Type Aliases§

  • Type for MIR Assert terminator error messages.
  • Types for locals
  • Alias for projections as they appear in places, where the base is a place and the index is a local.
  • Alias for projections as they appear in UserTypeProjection, where we need neither the V parameter for Index nor the T for Field.