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Diffstat (limited to 'src/doc/rustc-dev-guide/src/borrow_check/region_inference/closure_constraints.md')
| -rw-r--r-- | src/doc/rustc-dev-guide/src/borrow_check/region_inference/closure_constraints.md | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/src/doc/rustc-dev-guide/src/borrow_check/region_inference/closure_constraints.md b/src/doc/rustc-dev-guide/src/borrow_check/region_inference/closure_constraints.md new file mode 100644 index 000000000..13230d037 --- /dev/null +++ b/src/doc/rustc-dev-guide/src/borrow_check/region_inference/closure_constraints.md @@ -0,0 +1,10 @@ +# Propagating closure constraints + +When we are checking the type tests and universal regions, we may come +across a constraint that we can't prove yet if we are in a closure +body! However, the necessary constraints may actually hold (we just +don't know it yet). Thus, if we are inside a closure, we just collect +all the constraints we can't prove yet and return them. Later, when we +are borrow check the MIR node that created the closure, we can also +check that these constraints hold. At that time, if we can't prove +they hold, we report an error. |