X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=src%2Flibrustc%2Finfer%2Ferror_reporting%2Fmod.rs;h=2995b25308d4c9f455565cf6278f92fa3e3fd988;hb=0d883cb8f82ec5d99f63d03bd43c6fc87d96aeef;hp=4cce8343c02c871f83efe94c4c7f61ac84f92a5d;hpb=dd3e27357d47c4a983d40e19539e3abee22c532d;p=rust.git

diff --git a/src/librustc/infer/error_reporting/mod.rs b/src/librustc/infer/error_reporting/mod.rs
index 4cce8343c02..2995b25308d 100644
--- a/src/librustc/infer/error_reporting/mod.rs
+++ b/src/librustc/infer/error_reporting/mod.rs
@@ -487,6 +487,11 @@ fn check_and_note_conflicting_crates(
 
     fn note_error_origin(&self, err: &mut DiagnosticBuilder<'tcx>, cause: &ObligationCause<'tcx>) {
         match cause.code {
+            ObligationCauseCode::MatchExpressionArmPattern { span, ty } => {
+                if ty.is_suggestable() {  // don't show type `_`
+                    err.span_label(span, format!("this match expression has type `{}`", ty));
+                }
+            }
             ObligationCauseCode::MatchExpressionArm { arm_span, source } => match source {
                 hir::MatchSource::IfLetDesugar { .. } => {
                     let msg = "`if let` arm with an incompatible type";
@@ -506,6 +511,18 @@ fn note_error_origin(&self, err: &mut DiagnosticBuilder<'tcx>, cause: &Obligatio
                     }
                 }
             },
+            ObligationCauseCode::IfExpression { then, outer, semicolon } => {
+                err.span_label(then, "expected because of this");
+                outer.map(|sp| err.span_label(sp, "if and else have incompatible types"));
+                if let Some(sp) = semicolon {
+                    err.span_suggestion_short_with_applicability(
+                        sp,
+                        "consider removing this semicolon",
+                        String::new(),
+                        Applicability::MachineApplicable,
+                    );
+                }
+            }
             _ => (),
         }
     }
@@ -1455,7 +1472,7 @@ fn as_failure_code(&self, terr: &TypeError<'tcx>) -> FailureCode {
                 }
                 _ => "match arms have incompatible types",
             }),
-            IfExpression => Error0308("if and else have incompatible types"),
+            IfExpression { .. } => Error0308("if and else have incompatible types"),
             IfExpressionWithNoElse => Error0317("if may be missing an else clause"),
             MainFunctionType => Error0580("main function has wrong type"),
             StartFunctionType => Error0308("start function has wrong type"),
@@ -1483,7 +1500,7 @@ fn as_requirement_str(&self) -> &'static str {
                 hir::MatchSource::IfLetDesugar { .. } => "`if let` arms have compatible types",
                 _ => "match arms have compatible types",
             },
-            IfExpression => "if and else have compatible types",
+            IfExpression { .. } => "if and else have compatible types",
             IfExpressionWithNoElse => "if missing an else returns ()",
             MainFunctionType => "`main` function has the correct type",
             StartFunctionType => "`start` function has the correct type",