From bc36aabf5f4080521037d7ebe2be86302b6f7d81 Mon Sep 17 00:00:00 2001 From: David Wood Date: Thu, 13 Jun 2019 17:19:50 +0100 Subject: [PATCH] typeck: Fix ICE for blocks in repeat expr count. This commit extends the work in #61698 to get the `DefId` of const parameters from block that resolve to a const parameter (as well as const parameters directly, as it was previously). --- src/librustc_typeck/astconv.rs | 21 ++++++++----------- src/test/ui/const-generics/issue-61336-2.rs | 16 ++++++++++++++ .../ui/const-generics/issue-61336-2.stderr | 18 ++++++++++++++++ 3 files changed, 43 insertions(+), 12 deletions(-) create mode 100644 src/test/ui/const-generics/issue-61336-2.rs create mode 100644 src/test/ui/const-generics/issue-61336-2.stderr diff --git a/src/librustc_typeck/astconv.rs b/src/librustc_typeck/astconv.rs index 2c9309a1696cf..2f8b45bbcad3d 100644 --- a/src/librustc_typeck/astconv.rs +++ b/src/librustc_typeck/astconv.rs @@ -2157,6 +2157,14 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o { /// Returns the `DefId` of the constant parameter that the provided expression is a path to. pub fn const_param_def_id(&self, expr: &hir::Expr) -> Option { + // Unwrap a block, so that e.g. `{ P }` is recognised as a parameter. Const arguments + // currently have to be wrapped in curly brackets, so it's necessary to special-case. + let expr = match &expr.node { + ExprKind::Block(block, _) if block.stmts.is_empty() && block.expr.is_some() => + block.expr.as_ref().unwrap(), + _ => expr, + }; + match &expr.node { ExprKind::Path(hir::QPath::Resolved(_, path)) => match path.res { Res::Def(DefKind::ConstParam, did) => Some(did), @@ -2184,18 +2192,7 @@ impl<'o, 'gcx: 'tcx, 'tcx> dyn AstConv<'gcx, 'tcx> + 'o { ty, }; - let mut expr = &tcx.hir().body(ast_const.body).value; - - // Unwrap a block, so that e.g. `{ P }` is recognised as a parameter. Const arguments - // currently have to be wrapped in curly brackets, so it's necessary to special-case. - if let ExprKind::Block(block, _) = &expr.node { - if block.stmts.is_empty() { - if let Some(trailing) = &block.expr { - expr = &trailing; - } - } - } - + let expr = &tcx.hir().body(ast_const.body).value; if let Some(def_id) = self.const_param_def_id(expr) { // Find the name and index of the const parameter by indexing the generics of the // parent item and construct a `ParamConst`. diff --git a/src/test/ui/const-generics/issue-61336-2.rs b/src/test/ui/const-generics/issue-61336-2.rs new file mode 100644 index 0000000000000..604c14ee120a8 --- /dev/null +++ b/src/test/ui/const-generics/issue-61336-2.rs @@ -0,0 +1,16 @@ +#![feature(const_generics)] +//~^ WARN the feature `const_generics` is incomplete and may cause the compiler to crash + +fn f(x: T) -> [T; N] { + [x; {N}] +} + +fn g(x: T) -> [T; N] { + [x; {N}] + //~^ ERROR the trait bound `T: std::marker::Copy` is not satisfied [E0277] +} + +fn main() { + let x: [u32; 5] = f::(3); + assert_eq!(x, [3u32; 5]); +} diff --git a/src/test/ui/const-generics/issue-61336-2.stderr b/src/test/ui/const-generics/issue-61336-2.stderr new file mode 100644 index 0000000000000..a7135b62f8cff --- /dev/null +++ b/src/test/ui/const-generics/issue-61336-2.stderr @@ -0,0 +1,18 @@ +warning: the feature `const_generics` is incomplete and may cause the compiler to crash + --> $DIR/issue-61336-2.rs:1:12 + | +LL | #![feature(const_generics)] + | ^^^^^^^^^^^^^^ + +error[E0277]: the trait bound `T: std::marker::Copy` is not satisfied + --> $DIR/issue-61336-2.rs:9:5 + | +LL | [x; {N}] + | ^^^^^^^^ the trait `std::marker::Copy` is not implemented for `T` + | + = help: consider adding a `where T: std::marker::Copy` bound + = note: the `Copy` trait is required because the repeated element will be copied + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0277`.