compiler: remove unnecessary imports and qualified paths

compiler/rustc_const_eval/src/interpret/cast.rs

@@ -1,5 +1,4 @@
 use std::assert_matches::assert_matches;
-use std::convert::TryFrom;
 
 use rustc_apfloat::ieee::{Double, Single};
 use rustc_apfloat::{Float, FloatConvert};

compiler/rustc_const_eval/src/interpret/intrinsics.rs

@@ -2,8 +2,6 @@
 //! looking at their MIR. Intrinsics/functions supported here are shared by CTFE
 //! and miri.
 
-use std::convert::TryFrom;
-
 use rustc_hir::def_id::DefId;
 use rustc_middle::mir::{
     self,

compiler/rustc_const_eval/src/interpret/intrinsics/caller_location.rs

@@ -1,5 +1,3 @@
-use std::convert::TryFrom;
-
 use rustc_ast::Mutability;
 use rustc_hir::lang_items::LangItem;
 use rustc_middle::mir::TerminatorKind;

compiler/rustc_const_eval/src/interpret/operator.rs

@@ -1,5 +1,3 @@
-use std::convert::TryFrom;
-
 use rustc_apfloat::Float;
 use rustc_middle::mir;
 use rustc_middle::mir::interpret::{InterpResult, Scalar};

compiler/rustc_const_eval/src/interpret/util.rs

@@ -1,6 +1,5 @@
 use rustc_middle::mir::interpret::InterpResult;
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitor};
-use std::convert::TryInto;
 use std::ops::ControlFlow;
 
 /// Checks whether a type contains generic parameters which require substitution.

compiler/rustc_const_eval/src/interpret/validity.rs

@@ -4,7 +4,6 @@
 //! That's useful because it means other passes (e.g. promotion) can rely on `const`s
 //! to be const-safe.
 
-use std::convert::TryFrom;
 use std::fmt::{Display, Write};
 use std::num::NonZeroUsize;