in which the E0618 "expected function" diagnostic gets a makeover #55862
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Now the main span focuses on the erroneous not-a-function callee, while showing the entire call expression is relegated to a secondary span. In the case where the erroneous callee is itself a call, we point out the definition, and, if the call expression spans multiple lines, tentatively suggest a semicolon (because we suspect that the "outer" call is actually supposed to be a tuple). The new `bug!` assertion is, in fact, safe (`confirm_builtin_call` is only called by `check_call`, which is only called with a first arg of kind `ExprKind::Call` in `check_expr_kind`). Resolves rust-lang#51055.
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| | ^^^^ not a function | ||
| | ^--- | ||
| | | | ||
| | call expression requires function |
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I'm surprised at the parser taking this as a function call (but it's not problematic).
| LL | let x = foo(5)(2); | ||
| | ^^^^^^--- | ||
| | | | ||
| | call expression requires function |
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I wonder how muddled it'd be if you kept the "not a function" label pointing at the primary span. Even better, detecting chained calls would be nice to provide a custom message (follow up work that needs more thought put into it):
error[E0618]: expected function, found `()`
--> $DIR/issue-20862.rs:17:13
|
LL | / fn foo(x: i32) {
LL | | |y| x + y
LL | | //~^ ERROR: mismatched types
LL | | }
| |_- `foo` defined here returns `()`
...
LL | let x = foo(5)(2);
| ^^^^^^---
| |
| call expression requires function
= note: the highlighted code below resolves to `()`...
LL | let x = foo(5)(2);
| ^^^^^^
= note: ...which cannot be called with the arguments `(2)`
| LL | | |y| x + y | ||
| LL | | //~^ ERROR: mismatched types | ||
| LL | | } | ||
| | |_- `foo` defined here returns `()` |
| | _____| | ||
| | | | ||
| LL | | (1, 2) | ||
| | |__________- call expression requires function |
A little bit too cluttered, in my opinion.
@bors r=estebank |
|
📌 Commit f3e9b1a has been approved by |
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…you_call_them, r=estebank in which the E0618 "expected function" diagnostic gets a makeover A woman of wisdom once told me, "Better late than never." (Can't reopen the previously-closed pull request from six months ago [due to GitHub limitations](rust-lang#51098 (comment)).) Now the main span focuses on the erroneous not-a-function callee, while showing the entire call expression is relegated to a secondary span. In the case where the erroneous callee is itself a call, we point out the definition, and, if the call expression spans multiple lines, tentatively suggest a semicolon (because we suspect that the "outer" call is actually supposed to be a tuple).   The new `bug!` assertion is, in fact, safe (`confirm_builtin_call` is only called by `check_call`, which is only called with a first arg of kind `ExprKind::Call` in `check_expr_kind`). Resolves rust-lang#51055. r? @estebank
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Rollup of 25 pull requests Successful merges: - #55562 (Add powerpc- and powerpc64-unknown-linux-musl targets) - #55564 (test/linkage-visibility: Ignore on musl targets) - #55827 (A few tweaks to iterations/collecting) - #55834 (Forward the ABI of the non-zero sized fields of an union if they have the same ABI) - #55857 (remove unused dependency) - #55862 (in which the E0618 "expected function" diagnostic gets a makeover) - #55867 (do not panic just because cargo failed) - #55894 (miri enum discriminant handling: Fix treatment of pointers, better error when it is undef) - #55916 (Make miri value visitor usfeful for mutation) - #55919 (core/tests/num: Simplify `test_int_from_str_overflow()` test code) - #55923 (reword #[test] attribute error on fn items) - #55935 (appveyor: Use VS2017 for all our images) - #55949 (ty: return impl Iterator from Predicate::walk_tys) - #55952 (Update to Clang 7 on CI.) - #55953 (#53488 Refactoring UpvarId) - #55962 (rustdoc: properly calculate spans for intra-doc link resolution errors) - #55963 (Stress test for MPSC) - #55968 (Clean up some non-mod-rs stuff.) - #55970 (Miri backtrace improvements) - #56007 (CTFE: dynamically make sure we do not call non-const-fn) - #56011 (Replace data.clone() by Arc::clone(&data) in mutex doc.) - #56012 (avoid shared ref in UnsafeCell::get) - #56016 (Add VecDeque::resize_with) - #56027 (docs: Add missing backtick in object_safety.rs docs) - #56043 (remove "approx env bounds" if we already know from trait) Failed merges: r? @ghost
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Rollup of 25 pull requests Successful merges: - #55562 (Add powerpc- and powerpc64-unknown-linux-musl targets) - #55564 (test/linkage-visibility: Ignore on musl targets) - #55827 (A few tweaks to iterations/collecting) - #55834 (Forward the ABI of the non-zero sized fields of an union if they have the same ABI) - #55857 (remove unused dependency) - #55862 (in which the E0618 "expected function" diagnostic gets a makeover) - #55867 (do not panic just because cargo failed) - #55894 (miri enum discriminant handling: Fix treatment of pointers, better error when it is undef) - #55916 (Make miri value visitor useful for mutation) - #55919 (core/tests/num: Simplify `test_int_from_str_overflow()` test code) - #55923 (reword #[test] attribute error on fn items) - #55949 (ty: return impl Iterator from Predicate::walk_tys) - #55952 (Update to Clang 7 on CI.) - #55953 (#53488 Refactoring UpvarId) - #55962 (rustdoc: properly calculate spans for intra-doc link resolution errors) - #55963 (Stress test for MPSC) - #55968 (Clean up some non-mod-rs stuff.) - #55970 (Miri backtrace improvements) - #56007 (CTFE: dynamically make sure we do not call non-const-fn) - #56011 (Replace data.clone() by Arc::clone(&data) in mutex doc.) - #56012 (avoid shared ref in UnsafeCell::get) - #56016 (Add VecDeque::resize_with) - #56027 (docs: Add missing backtick in object_safety.rs docs) - #56043 (remove "approx env bounds" if we already know from trait) - #56059 (Increase `Duration` approximate equal threshold to 1us)
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A woman of wisdom once told me, "Better late than never." (Can't reopen the previously-closed pull request from six months ago due to GitHub limitations.)
Now the main span focuses on the erroneous not-a-function callee, while showing the entire call expression is relegated to a secondary span. In the case where the erroneous callee is itself a call, we
point out the definition, and, if the call expression spans multiple lines, tentatively suggest a semicolon (because we suspect that the "outer" call is actually supposed to be a tuple).
The new
bug!assertion is, in fact, safe (confirm_builtin_callis only called bycheck_call, which is only called with a first arg of kindExprKind::Callincheck_expr_kind).Resolves #51055.
r? @estebank