Auto merge of #33688 - jonathandturner:fix_old_school, r=nikomatsakis

Fix for old school error issues, improvements to new school

This PR:
* Fixes some old school error issues, specifically #33559, #33543, #33366
* Improves wording borrowck errors with match patterns
* De-emphasize multi-line spans, so we don't color the single source character when we're trying to say "span starts here"
* Rollup of #33392 (which should help fix #33390)

r? @nikomatsakis

2 files changed, 33 insertions, 21 deletions

diff --git a/src/tools/compiletest/src/json.rs b/src/tools/compiletest/src/json.rs
index 3501b335205..84b78547ab9 100644
--- a/src/tools/compiletest/src/json.rs
+++ b/src/tools/compiletest/src/json.rs
@@ -12,6 +12,7 @@ use errors::{Error, ErrorKind};
 use rustc_serialize::json;
 use std::str::FromStr;
 use std::path::Path;
+use runtest::{ProcRes};
 
 // These structs are a subset of the ones found in
 // `syntax::errors::json`.
@@ -55,13 +56,13 @@ struct DiagnosticCode {
     explanation: Option<String>,
 }
 
-pub fn parse_output(file_name: &str, output: &str) -> Vec<Error> {
+pub fn parse_output(file_name: &str, output: &str, proc_res: &ProcRes) -> Vec<Error> {
     output.lines()
-          .flat_map(|line| parse_line(file_name, line))
+          .flat_map(|line| parse_line(file_name, line, output, proc_res))
           .collect()
 }
 
-fn parse_line(file_name: &str, line: &str) -> Vec<Error> {
+fn parse_line(file_name: &str, line: &str, output: &str, proc_res: &ProcRes) -> Vec<Error> {
     // The compiler sometimes intermingles non-JSON stuff into the
     // output.  This hack just skips over such lines. Yuck.
     if line.chars().next() == Some('{') {
@@ -72,7 +73,9 @@ fn parse_line(file_name: &str, line: &str) -> Vec<Error> {
                 expected_errors
             }
             Err(error) => {
-                panic!("failed to decode compiler output as json: `{}`", error);
+                proc_res.fatal(Some(&format!(
+                    "failed to decode compiler output as json: `{}`\noutput: {}\nline: {}",
+                    error, line, output)));
             }
         }
     } else {
diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index f89ff6b3849..e6dc3a9d360 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -1003,7 +1003,7 @@ actual:\n\
         let expect_note = expected_errors.iter().any(|ee| ee.kind == Some(ErrorKind::Note));
 
         // Parse the JSON output from the compiler and extract out the messages.
-        let actual_errors = json::parse_output(&file_name, &proc_res.stderr);
+        let actual_errors = json::parse_output(&file_name, &proc_res.stderr, &proc_res);
         let mut unexpected = 0;
         let mut not_found = 0;
         let mut found = vec![false; expected_errors.len()];
@@ -1547,21 +1547,7 @@ actual:\n\
 
     fn fatal_proc_rec(&self, err: &str, proc_res: &ProcRes) -> ! {
         self.error(err);
-        print!("\
-            status: {}\n\
-            command: {}\n\
-            stdout:\n\
-            ------------------------------------------\n\
-            {}\n\
-            ------------------------------------------\n\
-            stderr:\n\
-            ------------------------------------------\n\
-            {}\n\
-            ------------------------------------------\n\
-            \n",
-               proc_res.status, proc_res.cmdline, proc_res.stdout,
-               proc_res.stderr);
-        panic!();
+        proc_res.fatal(None);
     }
 
     fn _arm_exec_compiled_test(&self, env: Vec<(String, String)>) -> ProcRes {
@@ -2211,7 +2197,7 @@ struct ProcArgs {
     args: Vec<String>,
 }
 
-struct ProcRes {
+pub struct ProcRes {
     status: Status,
     stdout: String,
     stderr: String,
@@ -2223,6 +2209,29 @@ enum Status {
     Normal(ExitStatus),
 }
 
+impl ProcRes {
+    pub fn fatal(&self, err: Option<&str>) -> ! {
+        if let Some(e) = err {
+            println!("\nerror: {}", e);
+        }
+        print!("\
+            status: {}\n\
+            command: {}\n\
+            stdout:\n\
+            ------------------------------------------\n\
+            {}\n\
+            ------------------------------------------\n\
+            stderr:\n\
+            ------------------------------------------\n\
+            {}\n\
+            ------------------------------------------\n\
+            \n",
+               self.status, self.cmdline, self.stdout,
+               self.stderr);
+        panic!();
+    }
+}
+
 impl Status {
     fn code(&self) -> Option<i32> {
         match *self {