From 439afcd9747808fb187b0676d63af5375a677e3d Mon Sep 17 00:00:00 2001 From: Jonathan Turner Date: Wed, 31 Aug 2016 17:48:26 -0700 Subject: [PATCH] Update error message for lifetime of borrowed values --- src/librustc_borrowck/borrowck/mod.rs | 22 ++++++++++------- .../borrowck-let-suggestion-suffixes.rs | 24 +++++++++---------- .../regions-escape-loop-via-vec.rs | 4 ++-- .../lifetimes}/borrowck-let-suggestion.rs | 5 ---- .../lifetimes/borrowck-let-suggestion.stderr | 14 +++++++++++ src/test/ui/span/issue-11925.stderr | 4 ++-- 6 files changed, 44 insertions(+), 29 deletions(-) rename src/test/{compile-fail/borrowck => ui/lifetimes}/borrowck-let-suggestion.rs (66%) create mode 100644 src/test/ui/lifetimes/borrowck-let-suggestion.stderr diff --git a/src/librustc_borrowck/borrowck/mod.rs b/src/librustc_borrowck/borrowck/mod.rs index e8b44d85bf916..ac8cfa7f43709 100644 --- a/src/librustc_borrowck/borrowck/mod.rs +++ b/src/librustc_borrowck/borrowck/mod.rs @@ -1029,6 +1029,12 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> { } err_out_of_scope(super_scope, sub_scope, cause) => { + let (value_kind, value_msg) = match err.cmt.cat { + mc::Categorization::Rvalue(_) => + ("temporary value", "temporary value created here"), + _ => + ("borrowed value", "does not live long enough") + }; match cause { euv::ClosureCapture(s) => { // The primary span starts out as the closure creation point. @@ -1039,13 +1045,13 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> { Some(primary) => { db.span = MultiSpan::from_span(s); db.span_label(primary, &format!("capture occurs here")); - db.span_label(s, &format!("does not live long enough")); + db.span_label(s, &value_msg); } None => () } } _ => { - db.span_label(error_span, &format!("does not live long enough")); + db.span_label(error_span, &value_msg); } } @@ -1054,14 +1060,15 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> { match (sub_span, super_span) { (Some(s1), Some(s2)) if s1 == s2 => { - db.span_label(s1, &"borrowed value dropped before borrower"); + db.span_label(s1, &format!("{} dropped before borrower", value_kind)); db.note("values in a scope are dropped in the opposite order \ they are created"); } _ => { match sub_span { Some(s) => { - db.span_label(s, &"borrowed value must be valid until here"); + db.span_label(s, &format!("{} needs to live until here", + value_kind)); } None => { self.tcx.note_and_explain_region( @@ -1073,7 +1080,7 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> { } match super_span { Some(s) => { - db.span_label(s, &"borrowed value only valid until here"); + db.span_label(s, &format!("{} only lives until here", value_kind)); } None => { self.tcx.note_and_explain_region( @@ -1086,9 +1093,8 @@ impl<'a, 'tcx> BorrowckCtxt<'a, 'tcx> { } } - if let Some(span) = statement_scope_span(self.tcx, super_scope) { - db.span_help(span, - "consider using a `let` binding to increase its lifetime"); + if let Some(_) = statement_scope_span(self.tcx, super_scope) { + db.note("consider using a `let` binding to increase its lifetime"); } } diff --git a/src/test/compile-fail/borrowck/borrowck-let-suggestion-suffixes.rs b/src/test/compile-fail/borrowck/borrowck-let-suggestion-suffixes.rs index 6c9f67b2b33d4..95c74348e788b 100644 --- a/src/test/compile-fail/borrowck/borrowck-let-suggestion-suffixes.rs +++ b/src/test/compile-fail/borrowck/borrowck-let-suggestion-suffixes.rs @@ -25,9 +25,9 @@ fn f() { v3.push(&'x'); // statement 6 //~^ ERROR borrowed value does not live long enough - //~| NOTE does not live long enough - //~| NOTE borrowed value only valid until here - //~| HELP consider using a `let` binding to increase its lifetime + //~| NOTE temporary value created here + //~| NOTE temporary value only lives until here + //~| NOTE consider using a `let` binding to increase its lifetime { @@ -35,26 +35,26 @@ fn f() { v4.push(&'y'); //~^ ERROR borrowed value does not live long enough - //~| NOTE does not live long enough - //~| NOTE borrowed value only valid until here - //~| HELP consider using a `let` binding to increase its lifetime + //~| NOTE temporary value created here + //~| NOTE temporary value only lives until here + //~| NOTE consider using a `let` binding to increase its lifetime } // (statement 7) - //~^ NOTE borrowed value must be valid until here + //~^ NOTE temporary value needs to live until here let mut v5 = Vec::new(); // statement 8 v5.push(&'z'); //~^ ERROR borrowed value does not live long enough - //~| NOTE does not live long enough - //~| NOTE borrowed value only valid until here - //~| HELP consider using a `let` binding to increase its lifetime + //~| NOTE temporary value created here + //~| NOTE temporary value only lives until here + //~| NOTE consider using a `let` binding to increase its lifetime v1.push(&old[0]); } //~^ NOTE borrowed value dropped before borrower -//~| NOTE borrowed value must be valid until here -//~| NOTE borrowed value must be valid until here +//~| NOTE temporary value needs to live until here +//~| NOTE temporary value needs to live until here fn main() { f(); diff --git a/src/test/compile-fail/regions-escape-loop-via-vec.rs b/src/test/compile-fail/regions-escape-loop-via-vec.rs index 8c026df7d9754..f5ea7a2108e79 100644 --- a/src/test/compile-fail/regions-escape-loop-via-vec.rs +++ b/src/test/compile-fail/regions-escape-loop-via-vec.rs @@ -24,8 +24,8 @@ fn broken() { x += 1; //~ ERROR cannot assign //~^ NOTE assignment to borrowed `x` occurs here } - //~^ NOTE borrowed value only valid until here + //~^ NOTE borrowed value only lives until here } -//~^ NOTE borrowed value must be valid until here +//~^ NOTE borrowed value needs to live until here fn main() { } diff --git a/src/test/compile-fail/borrowck/borrowck-let-suggestion.rs b/src/test/ui/lifetimes/borrowck-let-suggestion.rs similarity index 66% rename from src/test/compile-fail/borrowck/borrowck-let-suggestion.rs rename to src/test/ui/lifetimes/borrowck-let-suggestion.rs index ef8f44c1df789..eeafaab44c620 100644 --- a/src/test/compile-fail/borrowck/borrowck-let-suggestion.rs +++ b/src/test/ui/lifetimes/borrowck-let-suggestion.rs @@ -10,12 +10,7 @@ fn f() { let x = [1].iter(); - //~^ ERROR borrowed value does not live long enough - //~| NOTE does not live long enough - //~| NOTE borrowed value only valid until here - //~| HELP consider using a `let` binding to increase its lifetime } -//~^ borrowed value must be valid until here fn main() { f(); diff --git a/src/test/ui/lifetimes/borrowck-let-suggestion.stderr b/src/test/ui/lifetimes/borrowck-let-suggestion.stderr new file mode 100644 index 0000000000000..91600340019c3 --- /dev/null +++ b/src/test/ui/lifetimes/borrowck-let-suggestion.stderr @@ -0,0 +1,14 @@ +error: borrowed value does not live long enough + --> $DIR/borrowck-let-suggestion.rs:12:13 + | +12 | let x = [1].iter(); + | ^^^ - temporary value only lives until here + | | + | temporary value created here +13 | } + | - temporary value needs to live until here + | + = note: consider using a `let` binding to increase its lifetime + +error: aborting due to previous error + diff --git a/src/test/ui/span/issue-11925.stderr b/src/test/ui/span/issue-11925.stderr index d379cfc3d68a7..3fedb2884bc58 100644 --- a/src/test/ui/span/issue-11925.stderr +++ b/src/test/ui/span/issue-11925.stderr @@ -5,10 +5,10 @@ error: `x` does not live long enough | ^ | | | does not live long enough - | borrowed value only valid until here + | borrowed value only lives until here ... 23 | } - | - borrowed value must be valid until here + | - borrowed value needs to live until here error: aborting due to previous error